utm/abacus.thy
author zhang
Mon, 15 Oct 2012 13:23:52 +0000
changeset 371 48b231495281
parent 370 1ce04eb1c8ad
permissions -rw-r--r--
Some illustration added together with more explanations.

header {* 
 {\em abacus} a kind of register machine
*}

theory abacus
imports Main turing_basic
begin

text {*
  {\em Abacus} instructions:
*}

datatype abc_inst =
  -- {* @{text "Inc n"} increments the memory cell (or register) with address @{text "n"} by one.
     *}
     Inc nat
  -- {*
     @{text "Dec n label"} decrements the memory cell with address @{text "n"} by one. 
      If cell @{text "n"} is already zero, no decrements happens and the executio jumps to
      the instruction labeled by @{text "label"}.
     *}
   | Dec nat nat
  -- {*
  @{text "Goto label"} unconditionally jumps to the instruction labeled by @{text "label"}.
  *}
   | Goto nat
  

text {*
  Abacus programs are defined as lists of Abacus instructions.
*}
type_synonym abc_prog = "abc_inst list"

section {*
  Sample Abacus programs
  *}

text {*
  Abacus for addition and clearance.
*}
fun plus_clear :: "nat \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> abc_prog"  
  where
  "plus_clear m n e = [Dec m e, Inc n, Goto 0]"

text {*
  Abacus for clearing memory untis.
*}
fun clear :: "nat \<Rightarrow> nat \<Rightarrow> abc_prog"
  where
  "clear n e = [Dec n e, Goto 0]"

fun plus:: "nat \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> abc_prog"
  where
  "plus m n p e = [Dec m 4, Inc n, Inc p,
                   Goto 0, Dec p e, Inc m, Goto 4]"

fun mult :: "nat \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> abc_prog"
  where
  "mult m1 m2 n p e = [Dec m1 e]@ plus m1 m2 p 1"

fun expo :: "nat \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> abc_prog"
  where
  "expo n m1 m2 p e = [Inc n, Dec m1 e] @ mult m2 n n p 2"


text {*
  The state of Abacus machine.
  *}
type_synonym abc_state = nat

(* text {*
  The memory of Abacus machine is defined as a function from address to contents.
*}
type_synonym abc_mem = "nat \<Rightarrow> nat" *)

text {*
  The memory of Abacus machine is defined as a list of contents, with 
  every units addressed by index into the list.
  *}
type_synonym abc_lm = "nat list"

text {*
  Fetching contents out of memory. Units not represented by list elements are considered
  as having content @{text "0"}.
*}
fun abc_lm_v :: "abc_lm \<Rightarrow> nat \<Rightarrow> nat"
  where 
    "abc_lm_v lm n = (if (n < length lm) then (lm!n) else 0)"         

(*
fun abc_l2m :: "abc_lm \<Rightarrow> abc_mem"
  where 
    "abc_l2m lm = abc_lm_v lm"
*)

text {*
  Set the content of memory unit @{text "n"} to value @{text "v"}.
  @{text "am"} is the Abacus memory before setting.
  If address @{text "n"} is outside to scope of @{text "am"}, @{text "am"} 
  is extended so that @{text "n"} becomes in scope.
*}
fun abc_lm_s :: "abc_lm \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> abc_lm"
  where
    "abc_lm_s am n v = (if (n < length am) then (am[n:=v]) else 
                           am@ (replicate (n - length am) 0) @ [v])"


text {*
  The configuration of Abaucs machines consists of its current state and its
  current memory:
*}
type_synonym abc_conf_l = "abc_state \<times> abc_lm"

text {*
  Fetch instruction out of Abacus program:
*}

fun abc_fetch :: "nat \<Rightarrow> abc_prog \<Rightarrow> abc_inst option" 
  where
  "abc_fetch s p = (if (s < length p) then Some (p ! s)
                    else None)"

text {*
  Single step execution of Abacus machine. If no instruction is feteched, 
  configuration does not change.
*}
fun abc_step_l :: "abc_conf_l \<Rightarrow> abc_inst option \<Rightarrow> abc_conf_l"
  where
  "abc_step_l (s, lm) a = (case a of 
               None \<Rightarrow> (s, lm) |
               Some (Inc n)  \<Rightarrow> (let nv = abc_lm_v lm n in
                       (s + 1, abc_lm_s lm n (nv + 1))) |
               Some (Dec n e) \<Rightarrow> (let nv = abc_lm_v lm n in
                       if (nv = 0) then (e, abc_lm_s lm n 0) 
                       else (s + 1,  abc_lm_s lm n (nv - 1))) |
               Some (Goto n) \<Rightarrow> (n, lm) 
               )"

text {*
  Multi-step execution of Abacus machine.
*}
fun abc_steps_l :: "abc_conf_l \<Rightarrow> abc_prog \<Rightarrow> nat \<Rightarrow> abc_conf_l"
  where
  "abc_steps_l (s, lm) p 0 = (s, lm)" |
  "abc_steps_l (s, lm) p (Suc n) = abc_steps_l (abc_step_l (s, lm) (abc_fetch s p)) p n"

section {*
  Compiling Abacus machines into Truing machines
*}


subsection {*
  Compiling functions
*}

text {*
  @{text "findnth n"} returns the TM which locates the represention of
  memory cell @{text "n"} on the tape and changes representation of zero
  on the way.
*}

fun findnth :: "nat \<Rightarrow> tprog"
  where
  "findnth 0 = []" |
  "findnth (Suc n) = (findnth n @ [(W1, 2 * n + 1), 
           (R, 2 * n + 2), (R, 2 * n + 3), (R, 2 * n + 2)])"

text {*
  @{text "tinc_b"} returns the TM which increments the representation 
  of the memory cell under rw-head by one and move the representation 
  of cells afterwards to the right accordingly.
  *}

definition tinc_b :: "tprog"
  where
  "tinc_b \<equiv> [(W1, 1), (R, 2), (W1, 3), (R, 2), (W1, 3), (R, 4), 
             (L, 7), (W0, 5), (R, 6), (W0, 5), (W1, 3), (R, 6),
             (L, 8), (L, 7), (R, 9), (L, 7), (R, 10), (W0, 9)]" 

text {*
  @{text "tshift tm off"} shifts @{text "tm"} by offset @{text "off"}, leaving 
  instructions concerning state @{text "0"} unchanged, because state @{text "0"} 
  is the end state, which needs not be changed with shift operation.
  *}

fun tshift :: "tprog \<Rightarrow> nat \<Rightarrow> tprog"
  where
  "tshift tp off = (map (\<lambda> (action, state). 
       (action, (if state = 0 then 0
                 else state + off))) tp)"

text {*
  @{text "tinc ss n"} returns the TM which simulates the execution of 
  Abacus instruction @{text "Inc n"}, assuming that TM is located at
  location @{text "ss"} in the final TM complied from the whole
  Abacus program.
*}

fun tinc :: "nat \<Rightarrow> nat \<Rightarrow> tprog"
  where
  "tinc ss n = tshift (findnth n @ tshift tinc_b (2 * n)) (ss - 1)"

text {*
  @{text "tinc_b"} returns the TM which decrements the representation 
  of the memory cell under rw-head by one and move the representation 
  of cells afterwards to the left accordingly.
  *}

definition tdec_b :: "tprog"
  where
  "tdec_b \<equiv>  [(W1, 1), (R, 2), (L, 14), (R, 3), (L, 4), (R, 3),
              (R, 5), (W0, 4), (R, 6), (W0, 5), (L, 7), (L, 8),
              (L, 11), (W0, 7), (W1, 8), (R, 9), (L, 10), (R, 9),
              (R, 5), (W0, 10), (L, 12), (L, 11), (R, 13), (L, 11),
              (R, 17), (W0, 13), (L, 15), (L, 14), (R, 16), (L, 14),
              (R, 0), (W0, 16)]"

text {*
  @{text "sete tp e"} attaches the termination edges (edges leading to state @{text "0"}) 
  of TM @{text "tp"} to the intruction labelled by @{text "e"}.
  *}

fun sete :: "tprog \<Rightarrow> nat \<Rightarrow> tprog"
  where
  "sete tp e = map (\<lambda> (action, state). (action, if state = 0 then e else state)) tp"

text {*
  @{text "tdec ss n label"} returns the TM which simulates the execution of 
  Abacus instruction @{text "Dec n label"}, assuming that TM is located at
  location @{text "ss"} in the final TM complied from the whole
  Abacus program.
*}

fun tdec :: "nat \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> tprog"
  where
  "tdec ss n e = sete (tshift (findnth n @ tshift tdec_b (2 * n)) 
                 (ss - 1)) e"
 
text {*
  @{text "tgoto f(label)"} returns the TM simulating the execution of Abacus instruction
  @{text "Goto label"}, where @{text "f(label)"} is the corresponding location of
  @{text "label"} in the final TM compiled from the overall Abacus program.
*}

fun tgoto :: "nat \<Rightarrow> tprog"
  where
  "tgoto n = [(Nop, n), (Nop, n)]"

text {*
  The layout of the final TM compiled from an Abacus program is represented
  as a list of natural numbers, where the list element at index @{text "n"} represents the 
  starting state of the TM simulating the execution of @{text "n"}-th instruction
  in the Abacus program.
*}

type_synonym layout = "nat list"

text {*
  @{text "length_of i"} is the length of the 
  TM simulating the Abacus instruction @{text "i"}.
*}
fun length_of :: "abc_inst \<Rightarrow> nat"
  where
  "length_of i = (case i of 
                    Inc n   \<Rightarrow> 2 * n + 9 |
                    Dec n e \<Rightarrow> 2 * n + 16 |
                    Goto n  \<Rightarrow> 1)"

text {*
  @{text "layout_of ap"} returns the layout of Abacus program @{text "ap"}.
*}
fun layout_of :: "abc_prog \<Rightarrow> layout"
  where "layout_of ap = map length_of ap"


text {*
  @{text "start_of layout n"} looks out the starting state of @{text "n"}-th
  TM in the finall TM.
*}

fun start_of :: "nat list \<Rightarrow> nat \<Rightarrow> nat"
  where
  "start_of ly 0 = Suc 0" |
  "start_of ly (Suc as) = 
        (if as < length ly then start_of ly as + (ly ! as)
         else start_of ly as)"

text {*
  @{text "ci lo ss i"} complies Abacus instruction @{text "i"}
  assuming the TM of @{text "i"} starts from state @{text "ss"} 
  within the overal layout @{text "lo"}.
*}

fun ci :: "layout \<Rightarrow> nat \<Rightarrow> abc_inst \<Rightarrow> tprog"
  where
  "ci ly ss i = (case i of 
                    Inc n   \<Rightarrow> tinc ss n |
                    Dec n e \<Rightarrow> tdec ss n (start_of ly e) |
                    Goto n  \<Rightarrow> tgoto (start_of ly n))"

text {*
  @{text "tpairs_of ap"} transfroms Abacus program @{text "ap"} pairing
  every instruction with its starting state.
*}
fun tpairs_of :: "abc_prog \<Rightarrow> (nat \<times> abc_inst) list"
  where "tpairs_of ap = (zip (map (start_of (layout_of ap)) 
                         [0..<(length ap)]) ap)"


text {*
  @{text "tms_of ap"} returns the list of TMs, where every one of them simulates
  the corresponding Abacus intruction in @{text "ap"}.
*}

fun tms_of :: "abc_prog \<Rightarrow> tprog list"
  where "tms_of ap = map (\<lambda> (n, tm). ci (layout_of ap) n tm) 
                         (tpairs_of ap)"

text {*
  @{text "tm_of ap"} returns the final TM machine compiled from Abacus program @{text "ap"}.
*}
fun tm_of :: "abc_prog \<Rightarrow> tprog"
  where "tm_of ap = concat (tms_of ap)"

text {*
  The following two functions specify the well-formedness of complied TM.
*}
fun t_ncorrect :: "tprog \<Rightarrow> bool"
  where
  "t_ncorrect tp = (length tp mod 2 = 0)"

fun abc2t_correct :: "abc_prog \<Rightarrow> bool"
  where 
  "abc2t_correct ap = list_all (\<lambda> (n, tm). 
             t_ncorrect (ci (layout_of ap) n tm)) (tpairs_of ap)"

lemma findnth_length: "length (findnth n) div 2 = 2 * n"
apply(induct n, simp, simp)
done

lemma ci_length : "length (ci ns n ai) div 2 = length_of ai"
apply(auto simp: ci.simps tinc_b_def tdec_b_def findnth_length
                 split: abc_inst.splits)
done

subsection {*
  Representation of Abacus memory by TM tape
*}

consts tape_of :: "'a \<Rightarrow> block list" ("<_>" 100)

text {*
  @{text "tape_of_nat_list am"} returns the TM tape representing
  Abacus memory @{text "am"}.
  *}

fun tape_of_nat_list :: "nat list \<Rightarrow> block list"
  where 
  "tape_of_nat_list [] = []" |
  "tape_of_nat_list [n] = Oc\<^bsup>n+1\<^esup>" |
  "tape_of_nat_list (n#ns) = (Oc\<^bsup>n+1\<^esup>) @ [Bk] @ (tape_of_nat_list ns)"

defs (overloaded)
  tape_of_nl_abv: "<am> \<equiv> tape_of_nat_list am"
  tape_of_nat_abv : "<(n::nat)> \<equiv> Oc\<^bsup>n+1\<^esup>"

text {*
  @{text "crsp_l acf tcf"} meams the abacus configuration @{text "acf"}
  is corretly represented by the TM configuration @{text "tcf"}.
*}

fun crsp_l :: "layout \<Rightarrow> abc_conf_l \<Rightarrow> t_conf \<Rightarrow> block list \<Rightarrow> bool"
  where 
  "crsp_l ly (as, lm) (ts, (l, r)) inres = 
           (ts = start_of ly as \<and> (\<exists> rn. r = <lm> @ Bk\<^bsup>rn\<^esup>)
            \<and> l = Bk # Bk # inres)"

declare crsp_l.simps[simp del]

subsection {*
  A more general definition of TM execution. 
*}

(*
fun nnth_of :: "(taction \<times> nat) list \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> (taction \<times> nat)"
  where
  "nnth_of p s b = (if 2*s < length p 
                    then (p ! (2*s + b)) else (Nop, 0))"

thm nth_of.simps

fun nfetch :: "tprog \<Rightarrow> nat \<Rightarrow> block \<Rightarrow> taction \<times> nat"
  where
  "nfetch p 0 b = (Nop, 0)" |
  "nfetch p (Suc s) b = 
             (case b of 
                Bk \<Rightarrow> nnth_of p s 0 |
                Oc \<Rightarrow> nnth_of p s 1)"
*)

text {*
  @{text "t_step tcf (tp, ss)"} returns the result of one step exection of TM @{text "tp"}
  assuming @{text "tp"} starts from instial state @{text "ss"}.
*}

fun t_step :: "t_conf \<Rightarrow> (tprog \<times> nat) \<Rightarrow> t_conf"
  where 
  "t_step c (p, off) = 
           (let (state, leftn, rightn) = c in
            let (action, next_state) = fetch p (state-off)
                             (case rightn of 
                                [] \<Rightarrow> Bk | 
                                Bk # xs \<Rightarrow> Bk |
                                Oc # xs \<Rightarrow> Oc
                             ) 
             in 
            (next_state, new_tape action (leftn, rightn)))"


text {*
  @{text "t_steps tcf (tp, ss) n"} returns the result of @{text "n"}-step exection 
  of TM @{text "tp"} assuming @{text "tp"} starts from instial state @{text "ss"}.
*}

fun t_steps :: "t_conf \<Rightarrow> (tprog \<times> nat) \<Rightarrow> nat \<Rightarrow> t_conf"
  where
  "t_steps c (p, off) 0 = c" |
  "t_steps c (p, off) (Suc n) = t_steps 
                     (t_step c (p, off)) (p, off) n" 

lemma stepn: "t_steps c (p, off) (Suc n) = 
              t_step (t_steps c (p, off) n) (p, off)"
apply(induct n arbitrary: c, simp add: t_steps.simps)
apply(simp add: t_steps.simps)
done

text {*
  The type of invarints expressing correspondence between 
  Abacus configuration and TM configuration.
*}

type_synonym inc_inv_t = "abc_conf_l \<Rightarrow> t_conf \<Rightarrow> block list \<Rightarrow> bool"

declare tms_of.simps[simp del] tm_of.simps[simp del]
        layout_of.simps[simp del] abc_fetch.simps [simp del]  
        t_step.simps[simp del] t_steps.simps[simp del] 
        tpairs_of.simps[simp del] start_of.simps[simp del]
        fetch.simps [simp del] t_ncorrect.simps[simp del]
        new_tape.simps [simp del] ci.simps [simp del] length_of.simps[simp del] 
        layout_of.simps[simp del] crsp_l.simps[simp del]
        abc2t_correct.simps[simp del]

lemma tct_div2: "t_ncorrect tp \<Longrightarrow> (length tp) mod 2 = 0"
apply(simp add: t_ncorrect.simps)
done

lemma t_shift_fetch: 
    "\<lbrakk>t_ncorrect tp1; t_ncorrect tp; 
      length tp1 div 2 < a \<and> a \<le> length tp1 div 2 + length tp div 2\<rbrakk>
    \<Longrightarrow> fetch tp (a - length tp1 div 2) b = 
         fetch (tp1 @ tp @ tp2) a b"
apply(subgoal_tac "\<exists> x. a = length tp1 div 2 + x", erule exE, simp)
apply(case_tac x, simp)
apply(subgoal_tac "length tp1 div 2 + Suc nat = 
             Suc (length tp1 div 2 + nat)")
apply(simp only: fetch.simps nth_of.simps, auto)
apply(case_tac b, simp)
apply(subgoal_tac "2 * (length tp1 div 2) = length tp1", simp)
apply(subgoal_tac "2 * nat < length tp", simp add: nth_append, simp)
apply(simp add: t_ncorrect.simps, auto)
apply(subgoal_tac "2 * (length tp1 div 2) = length tp1", simp)
apply(subgoal_tac "2 * nat < length tp", simp add: nth_append, auto)
apply(simp add: t_ncorrect.simps, auto)
apply(rule_tac x = "a - length tp1 div 2" in exI, simp)
done

lemma t_shift_in_step:
      "\<lbrakk>t_step (a, aa, ba) (tp, length tp1 div 2) = (s, l, r);
        t_ncorrect tp1; t_ncorrect tp;
        length tp1 div 2 < a \<and> a \<le> length tp1 div 2 + length tp div 2\<rbrakk>
       \<Longrightarrow> t_step (a, aa, ba) (tp1 @ tp @ tp2, 0) = (s, l, r)"
apply(simp add: t_step.simps)
apply(subgoal_tac "fetch tp (a - length tp1 div 2) (case ba of [] \<Rightarrow> 
                   Bk | x # xs \<Rightarrow> x)
             = fetch (tp1 @ tp @ tp2) a (case ba of [] \<Rightarrow> Bk | x # xs
                   \<Rightarrow> x)")
apply(case_tac "fetch tp (a - length tp1 div 2) (case ba of [] \<Rightarrow> Bk
                | x # xs \<Rightarrow> x)")
apply(auto intro: t_shift_fetch)
apply(case_tac ba, simp, simp)
apply(case_tac aaa, simp, simp)
done

declare add_Suc_right[simp del]
lemma t_step_add: "t_steps c (p, off) (m + n) = 
          t_steps (t_steps c (p, off) m) (p, off) n"
apply(induct m arbitrary: n,  simp add: t_steps.simps, simp)
apply(subgoal_tac "t_steps c (p, off) (Suc (m + n)) = 
                         t_steps c (p, off) (m + Suc n)", simp)
apply(subgoal_tac "t_steps (t_steps c (p, off) m) (p, off) (Suc n) =
                t_steps (t_step (t_steps c (p, off) m) (p, off)) 
                         (p, off) n")
apply(simp, simp add: stepn)
apply(simp only: t_steps.simps)
apply(simp only: add_Suc_right)
done
declare add_Suc_right[simp]

lemma s_out_fetch: "\<lbrakk>t_ncorrect tp; 
        \<not> (length tp1 div 2 < a \<and> a \<le> length tp1 div 2 + 
         length tp div 2)\<rbrakk>
      \<Longrightarrow> fetch tp (a - length tp1 div 2) b = (Nop, 0)"
apply(auto)
apply(simp add: fetch.simps)
apply(subgoal_tac "\<exists> x. a - length tp1 div 2 = length tp div 2 + x")
apply(erule exE, simp)
apply(case_tac x, simp)
apply(auto simp add: fetch.simps)
apply(subgoal_tac "2 * (length tp div 2) =  length tp")
apply(auto simp: t_ncorrect.simps split: block.splits)
apply(rule_tac x = "a - length tp1 div 2 - length tp div 2" in exI
     , simp)
done 

lemma conf_keep_step: 
      "\<lbrakk>t_ncorrect tp; 
        \<not> (length tp1 div 2 < a \<and> a \<le> length tp1 div 2 + 
       length tp div 2)\<rbrakk>
      \<Longrightarrow> t_step (a, aa, ba) (tp, length tp1 div 2) = (0, aa, ba)"
apply(simp add: t_step.simps)
apply(subgoal_tac "fetch tp (a - length tp1 div 2) (case ba of [] \<Rightarrow> 
  Bk | Bk # xs \<Rightarrow> Bk | Oc # xs \<Rightarrow> Oc) = (Nop, 0)")
apply(simp add: new_tape.simps)
apply(rule s_out_fetch, simp, simp)
done

lemma conf_keep: 
      "\<lbrakk>t_ncorrect tp; 
        \<not> (length tp1 div 2 < a \<and>
        a \<le> length tp1 div 2 + length tp div 2); n > 0\<rbrakk>
      \<Longrightarrow> t_steps (a, aa, ba) (tp, length tp1 div 2) n = (0, aa, ba)"
apply(induct n, simp)
apply(case_tac n, simp add: t_steps.simps)
apply(rule_tac conf_keep_step, simp+)
apply(subgoal_tac " t_steps (a, aa, ba) 
               (tp, length tp1 div 2) (Suc (Suc nat))
         = t_step (t_steps (a, aa, ba) 
            (tp, length tp1 div 2) (Suc nat)) (tp, length tp1 div 2)")
apply(simp)
apply(rule_tac conf_keep_step, simp, simp)
apply(rule stepn)
done

lemma state_bef_inside: 
    "\<lbrakk>t_ncorrect tp1; t_ncorrect tp; 
      t_steps (s0, l0, r0) (tp, length tp1 div 2) stp = (s, l, r);
      length tp1 div 2 < s0 \<and> 
         s0 \<le> length tp1 div 2 + length tp div 2;
      length tp1 div 2 < s \<and> s \<le> length tp1 div 2 + length tp div 2; 
      n < stp; t_steps (s0, l0, r0) (tp, length tp1 div 2) n = 
      (a, aa, ba)\<rbrakk>
      \<Longrightarrow>  length tp1 div 2 < a \<and> 
         a \<le> length tp1 div 2 + length tp div 2"
apply(subgoal_tac "\<exists> x. stp = n + x", erule exE)
apply(simp only: t_step_add)
apply(rule classical)
apply(subgoal_tac "t_steps (a, aa, ba) 
          (tp, length tp1 div 2) x = (0, aa, ba)")
apply(simp)
apply(rule conf_keep, simp, simp, simp)
apply(rule_tac x = "stp - n" in exI, simp)
done

lemma turing_shift_inside: 
       "\<lbrakk>t_steps (s0, l0, r0) (tp, length tp1 div 2) stp = (s, l, r);
         length tp1 div 2 < s0 \<and> 
         s0 \<le> length tp1 div 2 + length tp div 2; 
         t_ncorrect tp1; t_ncorrect tp;
         length tp1 div 2 < s \<and> 
         s \<le> length tp1 div 2 + length tp div 2\<rbrakk>
       \<Longrightarrow> t_steps (s0, l0, r0) (tp1 @ tp @ tp2, 0) stp = (s, l, r)"
apply(induct stp arbitrary: s l r)
apply(simp add: t_steps.simps)
apply(subgoal_tac " t_steps (s0, l0, r0) 
        (tp, length tp1 div 2) (Suc stp)
                  = t_step (t_steps (s0, l0, r0) 
        (tp, length tp1 div 2) stp) (tp, length tp1 div 2)")
apply(case_tac "t_steps (s0, l0, r0) (tp, length tp1 div 2) stp")
apply(subgoal_tac "length tp1 div 2 < a \<and> 
            a \<le> length tp1 div 2 + length tp div 2")
apply(subgoal_tac "t_steps (s0, l0, r0) 
           (tp1 @ tp @ tp2, 0) stp = (a, b, c)")
apply(simp only: stepn, simp)
apply(rule_tac t_shift_in_step, simp+)
defer
apply(rule stepn)
apply(rule_tac n = stp and stp = "Suc stp" and a = a 
               and aa = b and ba = c in state_bef_inside, simp+)
done

lemma take_Suc_last[elim]: "Suc as \<le> length xs \<Longrightarrow> 
            take (Suc as) xs = take as xs @ [xs ! as]"
apply(induct xs arbitrary: as, simp, simp)
apply(case_tac as, simp, simp)
done

lemma concat_suc: "Suc as \<le> length xs \<Longrightarrow> 
       concat (take (Suc as) xs) = concat (take as xs) @ xs! as"
apply(subgoal_tac "take (Suc as) xs = take as xs @ [xs ! as]", simp)
by auto

lemma concat_take_suc_iff: "Suc n \<le> length tps \<Longrightarrow> 
       concat (take n tps) @ (tps ! n) = concat (take (Suc n) tps)"
apply(drule_tac concat_suc, simp)
done

lemma concat_drop_suc_iff: 
   "Suc n < length tps \<Longrightarrow> concat (drop (Suc n) tps) = 
           tps ! Suc n @ concat (drop (Suc (Suc n)) tps)"
apply(induct tps arbitrary: n, simp, simp)
apply(case_tac tps, simp, simp)
apply(case_tac n, simp, simp)
done

declare append_assoc[simp del]

lemma  tm_append: "\<lbrakk>n < length tps; tp = tps ! n\<rbrakk> \<Longrightarrow> 
           \<exists> tp1 tp2. concat tps = tp1 @ tp @ tp2 \<and> tp1 = 
              concat (take n tps) \<and> tp2 = concat (drop (Suc n) tps)"
apply(rule_tac x = "concat (take n tps)" in exI)
apply(rule_tac x = "concat (drop (Suc n) tps)" in exI)
apply(auto)
apply(induct n, simp)
apply(case_tac tps, simp, simp, simp)
apply(subgoal_tac "concat (take n tps) @ (tps ! n) = 
               concat (take (Suc n) tps)")
apply(simp only: append_assoc[THEN sym], simp only: append_assoc)
apply(subgoal_tac " concat (drop (Suc n) tps) = tps ! Suc n @ 
                  concat (drop (Suc (Suc n)) tps)", simp)
apply(rule_tac concat_drop_suc_iff, simp)
apply(rule_tac concat_take_suc_iff, simp)
done

declare append_assoc[simp]

lemma map_of:  "n < length xs \<Longrightarrow> (map f xs) ! n = f (xs ! n)"
by(auto)

lemma [simp]: "length (tms_of aprog) = length aprog"
apply(auto simp: tms_of.simps tpairs_of.simps)
done

lemma ci_nth: "\<lbrakk>ly = layout_of aprog; as < length aprog; 
                abc_fetch as aprog = Some ins\<rbrakk>
    \<Longrightarrow> ci ly (start_of ly as) ins = tms_of aprog ! as"
apply(simp add: tms_of.simps tpairs_of.simps 
      abc_fetch.simps  map_of del: map_append)
done

lemma t_split:"\<lbrakk>
        ly = layout_of aprog;
        as < length aprog; abc_fetch as aprog = Some ins\<rbrakk>
      \<Longrightarrow> \<exists> tp1 tp2. concat (tms_of aprog) = 
            tp1 @ (ci ly (start_of ly as) ins) @ tp2
            \<and> tp1 = concat (take as (tms_of aprog)) \<and> 
              tp2 = concat (drop (Suc as) (tms_of aprog))"
apply(insert tm_append[of "as" "tms_of aprog" 
                             "ci ly (start_of ly as) ins"], simp)
apply(subgoal_tac "ci ly (start_of ly as) ins = (tms_of aprog) ! as")
apply(subgoal_tac "length (tms_of aprog) = length aprog", simp, simp)
apply(rule_tac ci_nth, auto)
done

lemma math_sub: "\<lbrakk>x >= Suc 0; x - 1 = z\<rbrakk> \<Longrightarrow> x + y - Suc 0 = z + y"
by auto

lemma start_more_one: "as \<noteq> 0 \<Longrightarrow> start_of ly as >= Suc 0"
apply(induct as, simp add: start_of.simps)
apply(case_tac as, auto simp: start_of.simps)
done

lemma tm_ct: "\<lbrakk>abc2t_correct aprog; tp \<in> set (tms_of aprog)\<rbrakk> \<Longrightarrow> 
                           t_ncorrect tp"
apply(simp add: abc2t_correct.simps tms_of.simps)
apply(auto)
apply(simp add:list_all_iff, auto)
done

lemma div_apart: "\<lbrakk>x mod (2::nat) = 0; y mod 2 = 0\<rbrakk> 
          \<Longrightarrow> (x + y) div 2 = x div 2 + y div 2"
apply(drule mod_eqD)+
apply(auto)
done

lemma div_apart_iff: "\<lbrakk>x mod (2::nat) = 0; y mod 2 = 0\<rbrakk> \<Longrightarrow> 
           (x + y) mod 2 = 0"
apply(auto)
done

lemma tms_ct: "\<lbrakk>abc2t_correct aprog; n < length aprog\<rbrakk> \<Longrightarrow> 
         t_ncorrect (concat (take n (tms_of aprog)))"
apply(induct n, simp add: t_ncorrect.simps, simp)
apply(subgoal_tac "concat (take (Suc n) (tms_of aprog)) = 
        concat (take n (tms_of aprog)) @ (tms_of aprog ! n)", simp)
apply(simp add: t_ncorrect.simps)
apply(rule_tac div_apart_iff, simp)
apply(subgoal_tac "t_ncorrect (tms_of aprog ! n)", 
            simp add: t_ncorrect.simps)
apply(rule_tac tm_ct, simp)
apply(rule_tac nth_mem, simp add: tms_of.simps tpairs_of.simps)
apply(rule_tac concat_suc, simp add: tms_of.simps tpairs_of.simps)
done

lemma tcorrect_div2: "\<lbrakk>abc2t_correct aprog; Suc as < length aprog\<rbrakk>
  \<Longrightarrow> (length (concat (take as (tms_of aprog))) + length (tms_of aprog
 ! as)) div 2 = length (concat (take as (tms_of aprog))) div 2 + 
                 length (tms_of aprog ! as) div 2"
apply(subgoal_tac "t_ncorrect (tms_of aprog ! as)")
apply(subgoal_tac "t_ncorrect (concat (take as (tms_of aprog)))")
apply(rule_tac div_apart)
apply(rule tct_div2, simp)+
apply(erule_tac tms_ct, simp)
apply(rule_tac tm_ct, simp)
apply(rule_tac nth_mem)
apply(simp add: tms_of.simps tpairs_of.simps)
done

lemma [simp]: "length (layout_of aprog) = length aprog"
apply(auto simp: layout_of.simps)
done

lemma start_of_ind: "\<lbrakk>as < length aprog; ly = layout_of aprog\<rbrakk> \<Longrightarrow> 
       start_of ly (Suc as) = start_of ly as + 
                          length ((tms_of aprog) ! as) div 2"
apply(simp only: start_of.simps, simp)
apply(auto simp: start_of.simps tms_of.simps layout_of.simps 
                 tpairs_of.simps)
apply(simp add: ci_length)
done

lemma concat_take_suc: "Suc n \<le> length xs \<Longrightarrow>
  concat (take (Suc n) xs) = concat (take n xs) @ (xs ! n)"
apply(subgoal_tac "take (Suc n) xs =
                   take n xs @ [xs ! n]")
apply(auto)
done

lemma ci_length_not0: "Suc 0 <= length (ci ly as i) div 2"
apply(subgoal_tac "length (ci ly as i) div 2 = length_of i")
apply(simp add: length_of.simps split: abc_inst.splits)
apply(rule ci_length)
done
 
lemma findnth_length2: "length (findnth n) = 4 * n"
apply(induct n, simp)
apply(simp)
done

lemma ci_length2: "length (ci ly as i) = 2 * (length_of i)"
apply(simp add: ci.simps length_of.simps tinc_b_def tdec_b_def
              split: abc_inst.splits, auto)
apply(simp add: findnth_length2)+
done

lemma tm_mod2: "as < length aprog \<Longrightarrow> 
             length (tms_of aprog ! as) mod 2 = 0"
apply(simp add: tms_of.simps)
apply(subgoal_tac "map (\<lambda>(x, y). ci (layout_of aprog) x y) 
              (tpairs_of aprog) ! as
                = (\<lambda>(x, y). ci (layout_of aprog) x y) 
              ((tpairs_of aprog) ! as)", simp)
apply(case_tac "(tpairs_of aprog ! as)", simp)
apply(subgoal_tac "length (ci (layout_of aprog) a b) =
                 2 * (length_of b)", simp)
apply(rule ci_length2)
apply(rule map_of, simp add: tms_of.simps tpairs_of.simps)
done

lemma tms_mod2: "as \<le> length aprog \<Longrightarrow> 
        length (concat (take as (tms_of aprog))) mod 2 = 0"
apply(induct as, simp, simp)
apply(subgoal_tac "concat (take (Suc as) (tms_of aprog))
                  = concat (take as (tms_of aprog)) @ 
                       (tms_of aprog ! as)", auto)
apply(rule div_apart_iff, simp, rule tm_mod2, simp)
apply(rule concat_take_suc, simp add: tms_of.simps tpairs_of.simps)
done

lemma [simp]: "\<lbrakk>as < length aprog; (abc_fetch as aprog) = Some ins\<rbrakk>
       \<Longrightarrow> ci (layout_of aprog) 
          (start_of (layout_of aprog) as) (ins) \<in> set (tms_of aprog)"
apply(insert ci_nth[of "layout_of aprog" aprog as], simp)
done

lemma startof_not0: "start_of ly as > 0"
apply(induct as, simp add: start_of.simps)
apply(case_tac as, auto simp: start_of.simps)
done

declare abc_step_l.simps[simp del]
lemma pre_lheq: "\<lbrakk>tp = concat (take as (tms_of aprog));
   abc2t_correct aprog; as \<le> length aprog\<rbrakk> \<Longrightarrow> 
         start_of (layout_of aprog) as - Suc 0 = length tp div 2"
apply(induct as arbitrary: tp, simp add: start_of.simps, simp)
proof - 
  fix as tp
  assume h1: "\<And>tp. tp = concat (take as (tms_of aprog)) \<Longrightarrow> 
     start_of (layout_of aprog) as - Suc 0 = 
            length (concat (take as (tms_of aprog))) div 2"
  and h2: " abc2t_correct aprog" "Suc as \<le> length aprog" 
  from h2 show "start_of (layout_of aprog) (Suc as) - Suc 0 = 
          length (concat (take (Suc as) (tms_of aprog))) div 2"
    apply(insert h1[of "concat (take as (tms_of aprog))"], simp)
    apply(insert start_of_ind[of as aprog "layout_of aprog"], simp)
    apply(subgoal_tac "(take (Suc as) (tms_of aprog)) = 
            take as (tms_of aprog) @ [(tms_of aprog) ! as]", simp)
    apply(subgoal_tac "(length (concat (take as (tms_of aprog))) + 
                       length (tms_of aprog ! as)) div 2
            = length (concat (take as (tms_of aprog))) div 2 + 
              length (tms_of aprog ! as) div 2", simp)
    apply(subgoal_tac "start_of (layout_of aprog) as = 
       length (concat (take as (tms_of aprog))) div 2 + Suc 0", simp)
    apply(subgoal_tac "start_of (layout_of aprog) as > 0", simp, 
           rule_tac startof_not0)
    apply(insert tm_mod2[of as aprog], simp)
    apply(insert tms_mod2[of as aprog], simp, arith)
    apply(rule take_Suc_last, simp)
    done
qed

lemma crsp2stateq: 
  "\<lbrakk>as < length aprog; abc2t_correct aprog;
       crsp_l (layout_of aprog) (as, am) (a, aa, ba) inres\<rbrakk> \<Longrightarrow> 
        a = length (concat (take as (tms_of aprog))) div 2 + 1"
apply(simp add: crsp_l.simps)
apply(insert pre_lheq[of "(concat (take as (tms_of aprog)))" as aprog]
, simp)   
apply(subgoal_tac "start_of (layout_of aprog) as > 0", 
      auto intro: startof_not0)
done

lemma turing_shift_outside: 
     "\<lbrakk>t_steps (s0, l0, r0) (tp, length tp1 div 2) stp = (s, l, r); 
       s \<noteq> 0; stp > 0;
       length tp1 div 2 < s0 \<and> 
       s0 \<le> length tp1 div 2 + length tp div 2; 
       t_ncorrect tp1; t_ncorrect tp;
       \<not> (length tp1 div 2 < s \<and> 
      s \<le> length tp1 div 2 + length tp div 2)\<rbrakk>
    \<Longrightarrow> \<exists>stp' > 0. t_steps (s0, l0, r0) (tp1 @ tp @ tp2, 0) stp' 
                = (s, l, r)"
apply(rule_tac x = stp in exI)
apply(case_tac stp, simp add: t_steps.simps)
apply(simp only: stepn)
apply(case_tac "t_steps (s0, l0, r0) (tp, length tp1 div 2) nat")
apply(subgoal_tac "length tp1 div 2 < a \<and> 
                   a \<le> length tp1 div 2 + length tp div 2")
apply(subgoal_tac "t_steps (s0, l0, r0) (tp1 @ tp @ tp2, 0) nat 
                   = (a, b, c)", simp)
apply(rule_tac t_shift_in_step, simp+)
apply(rule_tac turing_shift_inside, simp+)
apply(rule classical)
apply(subgoal_tac "t_step (a,b,c) 
            (tp, length tp1 div 2) = (0, b, c)", simp)
apply(rule_tac conf_keep_step, simp+)
done

lemma turing_shift: 
  "\<lbrakk>t_steps (s0, (l0, r0)) (tp, (length tp1 div 2)) stp
   = (s, (l, r)); s \<noteq> 0; stp > 0;
  (length tp1 div 2 < s0 \<and> s0 <= length tp1 div 2 + length tp div 2);
  t_ncorrect tp1; t_ncorrect tp\<rbrakk> \<Longrightarrow> 
         \<exists> stp' > 0. t_steps (s0, (l0, r0)) (tp1 @ tp @ tp2, 0) stp' =
                    (s, (l, r))"
apply(case_tac "s > length tp1 div 2 \<and> 
              s <= length tp1 div 2 + length tp div 2")
apply(subgoal_tac " t_steps (s0, l0, r0) (tp1 @ tp @ tp2, 0) stp = 
                   (s, l, r)")
apply(rule_tac x = stp in exI, simp)
apply(rule_tac turing_shift_inside, simp+)
apply(rule_tac turing_shift_outside, simp+)
done

lemma inc_startof_not0:  "start_of ly as \<ge> Suc 0"
apply(induct as, simp add: start_of.simps)
apply(simp add: start_of.simps)
done

lemma s_crsp:
  "\<lbrakk>as < length aprog; abc_fetch as aprog = Some ins;
  abc2t_correct aprog;
  crsp_l (layout_of aprog) (as, am) (a, aa, ba) inres\<rbrakk> \<Longrightarrow>  
  length (concat (take as (tms_of aprog))) div 2 < a 
      \<and> a \<le> length (concat (take as (tms_of aprog))) div 2 + 
         length (ci (layout_of aprog) (start_of (layout_of aprog) as)
         ins) div 2"
apply(subgoal_tac "a = length (concat (take as (tms_of aprog))) div 
                   2 + 1", simp)
apply(rule_tac ci_length_not0)
apply(rule crsp2stateq, simp+)
done

lemma tms_out_ex:
  "\<lbrakk>ly = layout_of aprog; tprog = tm_of aprog;
  abc2t_correct aprog;
  crsp_l ly (as, am) tc inres; as < length aprog;
  abc_fetch as aprog = Some ins;
  t_steps tc (ci ly (start_of ly as) ins, 
  (start_of ly as) - 1) n = (s, l, r);
  n > 0; 
  abc_step_l (as, am) (abc_fetch as aprog) = (as', am');
  s = start_of ly as'
  \<rbrakk>
  \<Longrightarrow> \<exists> stp > 0. (t_steps tc (tprog, 0) stp = (s, (l, r)))"
apply(simp only: tm_of.simps)
apply(subgoal_tac "\<exists> tp1 tp2. concat (tms_of aprog) = 
      tp1 @ (ci ly (start_of ly as) ins) @ tp2
    \<and> tp1 = concat (take as (tms_of aprog)) \<and> 
      tp2 = concat (drop (Suc as) (tms_of aprog))")
apply(erule exE, erule exE, erule conjE, erule conjE,
      case_tac tc, simp)
apply(rule turing_shift)
apply(subgoal_tac "start_of (layout_of aprog) as - Suc 0 
                = length tp1 div 2", simp)
apply(rule_tac pre_lheq, simp, simp, simp)
apply(simp add: startof_not0, simp)
apply(rule_tac s_crsp, simp, simp, simp, simp)
apply(rule tms_ct, simp, simp)
apply(rule tm_ct, simp)
apply(subgoal_tac "ci (layout_of aprog) 
                 (start_of (layout_of aprog) as) ins
                = (tms_of aprog ! as)", simp)
apply(simp add: tms_of.simps tpairs_of.simps)
apply(simp add: tms_of.simps tpairs_of.simps abc_fetch.simps)
apply(erule_tac t_split, auto simp: tm_of.simps)
done

(*
subsection {* The compilation of @{text "Inc n"} *}
*)

text {*
  The lemmas in this section lead to the correctness of 
  the compilation of @{text "Inc n"} instruction.
*}

fun at_begin_fst_bwtn :: "inc_inv_t"
  where
  "at_begin_fst_bwtn (as, lm) (s, l, r) ires = 
      (\<exists> lm1 tn rn. lm1 = (lm @ (0\<^bsup>tn\<^esup>)) \<and> length lm1 = s \<and> 
          (if lm1 = [] then l = Bk # Bk # ires
           else l = [Bk]@<rev lm1>@Bk#Bk#ires) \<and> r = (Bk\<^bsup>rn\<^esup>))" 


fun at_begin_fst_awtn :: "inc_inv_t"
  where
  "at_begin_fst_awtn (as, lm) (s, l, r) ires = 
      (\<exists> lm1 tn rn. lm1 = (lm @ (0\<^bsup>tn\<^esup>)) \<and> length lm1 = s \<and>
         (if lm1 = []  then l = Bk # Bk # ires
          else l = [Bk]@<rev lm1>@Bk#Bk#ires) \<and> r = [Oc]@Bk\<^bsup>rn\<^esup>
  )"

fun at_begin_norm :: "inc_inv_t"
  where
  "at_begin_norm (as, lm) (s, l, r) ires= 
      (\<exists> lm1 lm2 rn. lm = lm1 @ lm2 \<and> length lm1 = s \<and> 
        (if lm1 = [] then l = Bk # Bk # ires
         else l = Bk # <rev lm1> @ Bk# Bk # ires ) \<and> r = <lm2> @ (Bk\<^bsup>rn\<^esup>))"

fun in_middle :: "inc_inv_t"
  where
  "in_middle (as, lm) (s, l, r) ires = 
      (\<exists> lm1 lm2 tn m ml mr rn. lm @ 0\<^bsup>tn\<^esup> = lm1 @ [m] @ lm2
       \<and> length lm1 = s \<and> m + 1 = ml + mr \<and>  
         ml \<noteq> 0 \<and> tn = s + 1 - length lm \<and> 
       (if lm1 = [] then l = Oc\<^bsup>ml\<^esup> @ Bk # Bk # ires 
        else l = (Oc\<^bsup>ml\<^esup>)@[Bk]@<rev lm1>@
                 Bk # Bk # ires) \<and> (r = (Oc\<^bsup>mr\<^esup>) @ [Bk] @ <lm2>@ (Bk\<^bsup>rn\<^esup>) \<or> 
      (lm2 = [] \<and> r = (Oc\<^bsup>mr\<^esup>)))
      )"

fun inv_locate_a :: "inc_inv_t"
  where "inv_locate_a (as, lm) (s, l, r) ires = 
     (at_begin_norm (as, lm) (s, l, r) ires \<or>
      at_begin_fst_bwtn (as, lm) (s, l, r) ires \<or>
      at_begin_fst_awtn (as, lm) (s, l, r) ires
      )"

fun inv_locate_b :: "inc_inv_t"
  where "inv_locate_b (as, lm) (s, l, r) ires = 
        (in_middle (as, lm) (s, l, r)) ires "

fun inv_after_write :: "inc_inv_t"
  where "inv_after_write (as, lm) (s, l, r) ires = 
           (\<exists> rn m lm1 lm2. lm = lm1 @ m # lm2 \<and>
             (if lm1 = [] then l = Oc\<^bsup>m\<^esup> @ Bk # Bk # ires
              else Oc # l = Oc\<^bsup>Suc m \<^esup>@ Bk # <rev lm1> @ 
                      Bk # Bk # ires) \<and> r = [Oc] @ <lm2> @ (Bk\<^bsup>rn\<^esup>))"

fun inv_after_move :: "inc_inv_t"
  where "inv_after_move (as, lm) (s, l, r) ires = 
      (\<exists> rn m lm1 lm2. lm = lm1 @ m # lm2 \<and>
        (if lm1 = [] then l = Oc\<^bsup>Suc m\<^esup> @ Bk # Bk # ires
         else l = Oc\<^bsup>Suc m\<^esup>@ Bk # <rev lm1> @ Bk # Bk # ires) \<and> 
        r = <lm2> @ (Bk\<^bsup>rn\<^esup>))"

fun inv_after_clear :: "inc_inv_t"
  where "inv_after_clear (as, lm) (s, l, r) ires =
       (\<exists> rn m lm1 lm2 r'. lm = lm1 @ m # lm2 \<and> 
        (if lm1 = [] then l = Oc\<^bsup>Suc m\<^esup> @ Bk # Bk # ires
         else l = Oc\<^bsup>Suc m\<^esup>@ Bk # <rev lm1> @ Bk # Bk # ires) \<and> 
          r = Bk # r' \<and> Oc # r' = <lm2> @ (Bk\<^bsup>rn\<^esup>))"

fun inv_on_right_moving :: "inc_inv_t"
  where "inv_on_right_moving (as, lm) (s, l, r) ires = 
       (\<exists> lm1 lm2 m ml mr rn. lm = lm1 @ [m] @ lm2 \<and> 
            ml + mr = m \<and> 
          (if lm1 = [] then l = Oc\<^bsup>ml\<^esup> @ Bk # Bk # ires
          else l = (Oc\<^bsup>ml\<^esup>) @ [Bk] @ <rev lm1> @ Bk # Bk # ires) \<and> 
         ((r = (Oc\<^bsup>mr\<^esup>) @ [Bk] @ <lm2> @ (Bk\<^bsup>rn\<^esup>)) \<or> 
          (r = (Oc\<^bsup>mr\<^esup>) \<and> lm2 = [])))"

fun inv_on_left_moving_norm :: "inc_inv_t"
  where "inv_on_left_moving_norm (as, lm) (s, l, r) ires =
      (\<exists> lm1 lm2 m ml mr rn. lm = lm1 @ [m] @ lm2 \<and>  
             ml + mr = Suc m \<and> mr > 0 \<and> (if lm1 = [] then l = Oc\<^bsup>ml\<^esup> @ Bk # Bk # ires
                                         else l = (Oc\<^bsup>ml\<^esup>) @ Bk # <rev lm1> @ Bk # Bk # ires)
        \<and> (r = (Oc\<^bsup>mr\<^esup>) @ Bk # <lm2> @ (Bk\<^bsup>rn\<^esup>) \<or> 
           (lm2 = [] \<and> r = Oc\<^bsup>mr\<^esup>)))"

fun inv_on_left_moving_in_middle_B:: "inc_inv_t"
  where "inv_on_left_moving_in_middle_B (as, lm) (s, l, r) ires =
                (\<exists> lm1 lm2 rn. lm = lm1 @ lm2 \<and>  
                     (if lm1 = [] then l = Bk # ires
                      else l = <rev lm1> @ Bk # Bk # ires) \<and> 
                      r = Bk # <lm2> @ (Bk\<^bsup>rn\<^esup>))"

fun inv_on_left_moving :: "inc_inv_t"
  where "inv_on_left_moving (as, lm) (s, l, r) ires = 
       (inv_on_left_moving_norm  (as, lm) (s, l, r) ires \<or>
        inv_on_left_moving_in_middle_B (as, lm) (s, l, r) ires)"


fun inv_check_left_moving_on_leftmost :: "inc_inv_t"
  where "inv_check_left_moving_on_leftmost (as, lm) (s, l, r) ires = 
                (\<exists> rn. l = ires \<and> r = [Bk, Bk] @ <lm> @ (Bk\<^bsup>rn\<^esup>))"

fun inv_check_left_moving_in_middle :: "inc_inv_t"
  where "inv_check_left_moving_in_middle (as, lm) (s, l, r) ires = 

              (\<exists> lm1 lm2 r' rn. lm = lm1 @ lm2 \<and>
                 (Oc # l = <rev lm1> @ Bk # Bk # ires) \<and> r = Oc # Bk # r' \<and> 
                           r' = <lm2> @ (Bk\<^bsup>rn\<^esup>))"

fun inv_check_left_moving :: "inc_inv_t"
  where "inv_check_left_moving (as, lm) (s, l, r) ires = 
             (inv_check_left_moving_on_leftmost (as, lm) (s, l, r) ires \<or>
             inv_check_left_moving_in_middle (as, lm) (s, l, r) ires)"

fun inv_after_left_moving :: "inc_inv_t"
  where "inv_after_left_moving (as, lm) (s, l, r) ires= 
              (\<exists> rn. l = Bk # ires \<and> r = Bk # <lm> @ (Bk\<^bsup>rn\<^esup>))"

fun inv_stop :: "inc_inv_t"
  where "inv_stop (as, lm) (s, l, r) ires= 
              (\<exists> rn. l = Bk # Bk # ires \<and> r = <lm> @ (Bk\<^bsup>rn\<^esup>))"


fun inc_inv :: "layout \<Rightarrow> nat \<Rightarrow> inc_inv_t"
  where
  "inc_inv ly n (as, lm) (s, l, r) ires =
              (let ss = start_of ly as in
               let lm' = abc_lm_s lm n ((abc_lm_v lm n)+1) in
                if s = 0 then False
                else if s < ss then False
                else if s < ss + 2 * n then 
                   if (s - ss) mod 2 = 0 then 
                       inv_locate_a (as, lm) ((s - ss) div 2, l, r) ires
                   else inv_locate_b (as, lm) ((s - ss) div 2, l, r) ires
                else if s = ss + 2 * n then 
                        inv_locate_a (as, lm) (n, l, r) ires
                else if s = ss + 2 * n + 1 then 
                   inv_locate_b (as, lm) (n, l, r) ires
                else if s = ss + 2 * n + 2 then 
                   inv_after_write (as, lm') (s - ss, l, r) ires
                else if s = ss + 2 * n + 3 then 
                   inv_after_move (as, lm') (s - ss, l, r) ires
                else if s = ss + 2 * n + 4 then 
                   inv_after_clear (as, lm') (s - ss, l, r) ires
                else if s = ss + 2 * n + 5 then 
                   inv_on_right_moving (as, lm') (s - ss, l, r) ires
                else if s = ss + 2 * n + 6 then 
                   inv_on_left_moving (as, lm') (s - ss, l, r) ires
                else if s = ss + 2 * n + 7 then 
                   inv_check_left_moving (as, lm') (s - ss, l, r) ires
                else if s = ss + 2 * n + 8 then 
                   inv_after_left_moving (as, lm') (s - ss, l, r) ires
                else if s = ss + 2 * n + 9 then 
                   inv_stop (as, lm') (s - ss, l, r) ires
                else False) "

lemma fetch_intro: 
  "\<lbrakk>\<And>xs.\<lbrakk>ba = Oc # xs\<rbrakk> \<Longrightarrow> P (fetch prog i Oc);
   \<And>xs.\<lbrakk>ba = Bk # xs\<rbrakk> \<Longrightarrow> P (fetch prog i Bk);
   ba = [] \<Longrightarrow> P (fetch prog i Bk)
   \<rbrakk> \<Longrightarrow> P (fetch prog i 
             (case ba of [] \<Rightarrow> Bk | Bk # xs \<Rightarrow> Bk | Oc # xs \<Rightarrow> Oc))"
by (auto split:list.splits block.splits)

lemma length_findnth[simp]: "length (findnth n) = 4 * n"
apply(induct n, simp)
apply(simp)
done

declare tshift.simps[simp del]
declare findnth.simps[simp del]

lemma findnth_nth: 
 "\<lbrakk>n > q; x < 4\<rbrakk> \<Longrightarrow> 
        (findnth n) ! (4 * q + x) = (findnth (Suc q) ! (4 * q + x))"
apply(induct n, simp)
apply(case_tac "q < n", simp add: findnth.simps, auto)
apply(simp add: nth_append)
apply(subgoal_tac "q = n", simp)
apply(arith)
done

lemma Suc_pre[simp]: "\<not> a < start_of ly as \<Longrightarrow> 
          (Suc a - start_of ly as) = Suc (a - start_of ly as)"
apply(arith)
done

lemma fetch_locate_a_o: "
\<And>a  q xs.
    \<lbrakk>\<not> a < start_of (layout_of aprog) as; 
      a < start_of (layout_of aprog) as + 2 * n; 
      a - start_of (layout_of aprog) as = 2 * q; 
      start_of (layout_of aprog) as > 0\<rbrakk>
    \<Longrightarrow> (fetch (ci (layout_of aprog) (start_of (layout_of aprog) as)
         (Inc n)) (Suc (2 * q)) Oc) = (R, a+1)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append Suc_pre)
apply(subgoal_tac "(findnth n ! Suc (4 * q)) = 
                 findnth (Suc q) ! (4 * q + 1)")
apply(simp add: findnth.simps nth_append)
apply(subgoal_tac " findnth n !(4 * q + 1) = 
                 findnth (Suc q) ! (4 * q + 1)", simp)
apply(rule_tac findnth_nth, auto)
done

lemma fetch_locate_a_b: "
\<And>a  q xs.
    \<lbrakk>abc_fetch as aprog = Some (Inc n);  
     \<not> a < start_of (layout_of aprog) as; 
     a < start_of (layout_of aprog) as + 2 * n; 
     a - start_of (layout_of aprog) as = 2 * q; 
     start_of (layout_of aprog) as > 0\<rbrakk>
    \<Longrightarrow> (fetch (ci (layout_of aprog) 
      (start_of (layout_of aprog) as) (Inc n)) (Suc (2 * q)) Bk)
       = (W1, a)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                 tshift.simps nth_append)
apply(subgoal_tac "(findnth n ! (4 * q)) = 
                           findnth (Suc q) ! (4 * q )")
apply(simp add: findnth.simps nth_append)
apply(subgoal_tac " findnth n !(4 * q + 0) =
                            findnth (Suc q) ! (4 * q + 0)", simp)
apply(rule_tac findnth_nth, auto)
done

lemma [intro]: "x mod 2 = Suc 0 \<Longrightarrow> \<exists> q. x = Suc (2 * q)"
apply(drule mod_eqD, auto)
done

lemma  add3_Suc: "x + 3 = Suc (Suc (Suc x))"
apply(arith)
done

declare start_of.simps[simp]
(*
lemma layout_not0: "start_of ly as > 0"
by(induct as, auto)
*)
lemma [simp]: 
 "\<lbrakk>\<not> a < start_of (layout_of aprog) as; 
   a - start_of (layout_of aprog) as = Suc (2 * q); 
   abc_fetch as aprog = Some (Inc n); 
   start_of (layout_of aprog) as > 0\<rbrakk>
    \<Longrightarrow> Suc (Suc (2 * q + start_of (layout_of aprog) as - Suc 0)) = a"
apply(subgoal_tac 
"Suc (Suc (2 * q + start_of (layout_of aprog) as - Suc 0)) 
              = 2 + 2 * q + start_of (layout_of aprog) as - Suc 0", 
  simp, simp add: inc_startof_not0)
done

lemma fetch_locate_b_o: "
\<And>a  xs.
    \<lbrakk>0 < a; \<not> a < start_of (layout_of aprog) as; 
  a < start_of (layout_of aprog) as + 2 * n; 
 (a - start_of (layout_of aprog) as) mod 2 = Suc 0; 
 start_of (layout_of aprog) as > 0\<rbrakk>
    \<Longrightarrow> (fetch (ci (layout_of aprog) (start_of (layout_of aprog) as) 
      (Inc n)) (Suc (a - start_of (layout_of aprog) as)) Oc) = (R, a)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                 nth_of.simps tshift.simps nth_append)
apply(subgoal_tac "\<exists> q. (a - start_of (layout_of aprog) as) = 
                         2 * q + 1", auto)
apply(subgoal_tac "(findnth n ! Suc (Suc (Suc (4 * q)))) 
                  = findnth (Suc q) ! (4 * q + 3)")
apply(simp add: findnth.simps nth_append)
apply(subgoal_tac " findnth n ! (4 * q + 3) = 
                 findnth (Suc q) ! (4 * q + 3)", simp add: add3_Suc)
apply(rule_tac findnth_nth, auto)
done

lemma fetch_locate_b_b: "
\<And>a  xs.
    \<lbrakk>0 < a;  \<not> a < start_of (layout_of aprog) as; 
     a < start_of (layout_of aprog) as + 2 * n; 
     (a - start_of (layout_of aprog) as) mod 2 = Suc 0; 
     start_of (layout_of aprog) as > 0\<rbrakk>
    \<Longrightarrow> (fetch (ci (layout_of aprog) (start_of (layout_of aprog) as)
        (Inc n)) (Suc (a - start_of (layout_of aprog) as)) Bk) 
        = (R, a + 1)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append)
apply(subgoal_tac "\<exists> q. (a - start_of (layout_of aprog) as) = 
                  2 * q + 1", auto)
apply(subgoal_tac "(findnth n ! Suc ((Suc (4 * q)))) = 
                    findnth (Suc q) ! (4 * q + 2)")
apply(simp add: findnth.simps nth_append)
apply(subgoal_tac " findnth n ! (4 * q + 2) = 
                    findnth (Suc q) ! (4 * q + 2)", simp)
apply(rule_tac findnth_nth, auto)
done

lemma fetch_locate_n_a_o: 
       "start_of (layout_of aprog) as > 0
       \<Longrightarrow> (fetch (ci (layout_of aprog) 
      (start_of (layout_of aprog) as) (Inc n)) (Suc (2 * n)) Oc) = 
             (R, start_of (layout_of aprog) as + 2 * n + 1)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tinc_b_def)
done

lemma fetch_locate_n_a_b: "
       start_of (layout_of aprog) as > 0
      \<Longrightarrow> (fetch (ci (layout_of aprog) 
    (start_of (layout_of aprog) as) (Inc n)) (Suc (2 * n)) Bk) 
   = (W1, start_of (layout_of aprog) as + 2 * n)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tinc_b_def)
done

lemma fetch_locate_n_b_o: "
    start_of (layout_of aprog) as > 0
    \<Longrightarrow> (fetch (ci (layout_of aprog) (start_of (layout_of aprog) as) 
     (Inc n)) (Suc (Suc (2 * n))) Oc) = 
                      (R, start_of (layout_of aprog) as + 2 * n + 1)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tinc_b_def)
done

lemma fetch_locate_n_b_b: "
    start_of (layout_of aprog) as > 0
   \<Longrightarrow> (fetch (ci (layout_of aprog) (start_of (layout_of aprog) as) 
   (Inc n)) (Suc (Suc (2 * n))) Bk) = 
       (W1, start_of (layout_of aprog) as + 2 * n + 2)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tinc_b_def)
done

lemma fetch_after_write_o: "
    start_of (layout_of aprog) as > 0
    \<Longrightarrow> (fetch (ci (layout_of aprog) (start_of (layout_of aprog) as) 
            (Inc n)) (Suc (Suc (Suc (2 * n)))) Oc) = 
        (R, start_of (layout_of aprog) as + 2*n + 3)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tinc_b_def)
done

lemma fetch_after_move_o: "
      start_of (layout_of aprog) as > 0
      \<Longrightarrow> (fetch (ci (layout_of aprog) 
              (start_of (layout_of aprog) as) (Inc n)) (4 + 2 * n) Oc)
        = (W0, start_of (layout_of aprog) as + 2 * n + 4)"
apply(auto simp: ci.simps findnth.simps tshift.simps 
                 tinc_b_def add3_Suc)
apply(subgoal_tac "4 + 2*n = Suc (2*n + 3)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma fetch_after_move_b: "
      start_of (layout_of aprog) as > 0
      \<Longrightarrow>(fetch (ci (layout_of aprog) 
            (start_of (layout_of aprog) as) (Inc n)) (4 + 2 * n) Bk)
       = (L, start_of (layout_of aprog) as + 2 * n + 6)"
apply(auto simp: ci.simps findnth.simps tshift.simps 
                 tinc_b_def add3_Suc)
apply(subgoal_tac "4 + 2*n = Suc (2*n + 3)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma fetch_clear_b: "
     start_of (layout_of aprog) as > 0
      \<Longrightarrow> (fetch (ci (layout_of aprog) 
              (start_of (layout_of aprog) as) (Inc n)) (5 + 2 * n) Bk)
      = (R, start_of (layout_of aprog) as + 2 * n + 5)"
apply(auto simp: ci.simps findnth.simps 
                     tshift.simps tinc_b_def add3_Suc)
apply(subgoal_tac "5 + 2*n = Suc (2*n + 4)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma fetch_right_move_o: "
      start_of (layout_of aprog) as > 0
      \<Longrightarrow> (fetch (ci (layout_of aprog) 
                (start_of (layout_of aprog) as) (Inc n)) (6 + 2*n) Oc)
      = (R, start_of (layout_of aprog) as + 2 * n + 5)"
apply(auto simp: ci.simps findnth.simps tshift.simps 
                 tinc_b_def add3_Suc)
apply(subgoal_tac "6 + 2*n = Suc (2*n + 5)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma fetch_right_move_b: "
      start_of (layout_of aprog) as > 0
      \<Longrightarrow> (fetch (ci (layout_of aprog) 
                (start_of (layout_of aprog) as) (Inc n)) (6 + 2*n) Bk)
      = (W1, start_of (layout_of aprog) as + 2 * n + 2)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tinc_b_def add3_Suc)
apply(subgoal_tac "6 + 2*n = Suc (2*n + 5)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma fetch_left_move_o: "
      start_of (layout_of aprog) as > 0
      \<Longrightarrow> (fetch (ci (layout_of aprog) 
               (start_of (layout_of aprog) as) (Inc n)) (7 + 2*n) Oc)
      = (L, start_of (layout_of aprog) as + 2 * n + 6)"
apply(auto simp: ci.simps findnth.simps tshift.simps 
                 tinc_b_def add3_Suc)
apply(subgoal_tac "7 + 2*n = Suc (2*n + 6)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma fetch_left_move_b: "
      start_of (layout_of aprog) as > 0
      \<Longrightarrow> (fetch (ci (layout_of aprog) 
               (start_of (layout_of aprog) as) (Inc n)) (7 + 2*n) Bk)
      = (L, start_of (layout_of aprog) as + 2 * n + 7)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tinc_b_def add3_Suc)
apply(subgoal_tac "7 + 2*n = Suc (2*n + 6)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma fetch_check_left_move_o: "
      start_of (layout_of aprog) as > 0
      \<Longrightarrow> (fetch (ci (layout_of aprog) 
               (start_of (layout_of aprog) as) (Inc n)) (8 + 2*n) Oc)
      = (L, start_of (layout_of aprog) as + 2 * n + 6)"
apply(auto simp: ci.simps findnth.simps tshift.simps tinc_b_def)
apply(subgoal_tac "8 + 2 * n = Suc (2 * n + 7)", 
                                  simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma fetch_check_left_move_b: "
      start_of (layout_of aprog) as > 0
      \<Longrightarrow> (fetch (ci (layout_of aprog) 
              (start_of (layout_of aprog) as) (Inc n)) (8 + 2*n) Bk)
      = (R, start_of (layout_of aprog) as + 2 * n + 8)  "
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tinc_b_def add3_Suc)
apply(subgoal_tac "8 + 2*n= Suc (2*n + 7)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma fetch_after_left_move: "
      start_of (layout_of aprog) as > 0
      \<Longrightarrow> (fetch (ci (layout_of aprog) 
              (start_of (layout_of aprog) as) (Inc n)) (9 + 2*n) Bk)
     = (R, start_of (layout_of aprog) as + 2 * n + 9)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tinc_b_def)
done

lemma fetch_stop: "
       start_of (layout_of aprog) as > 0
      \<Longrightarrow> (fetch (ci (layout_of aprog) 
             (start_of (layout_of aprog) as) (Inc n)) (10 + 2 *n)  b)
     = (Nop, 0)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tinc_b_def
            split: block.splits)
done

lemma fetch_state0: "
       (fetch (ci (layout_of aprog) 
               (start_of (layout_of aprog) as) (Inc n)) 0 b)
     = (Nop, 0)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tinc_b_def)
done

lemmas fetch_simps = 
  fetch_locate_a_o fetch_locate_a_b fetch_locate_b_o fetch_locate_b_b 
  fetch_locate_n_a_b fetch_locate_n_a_o fetch_locate_n_b_o 
  fetch_locate_n_b_b fetch_after_write_o fetch_after_move_o 
  fetch_after_move_b fetch_clear_b fetch_right_move_o 
  fetch_right_move_b fetch_left_move_o fetch_left_move_b
  fetch_after_left_move fetch_check_left_move_o fetch_stop 
  fetch_state0 fetch_check_left_move_b

text {* *}
declare exponent_def[simp del] tape_of_nat_list.simps[simp del] 
   at_begin_norm.simps[simp del] at_begin_fst_bwtn.simps[simp del] 
   at_begin_fst_awtn.simps[simp del] in_middle.simps[simp del] 
   abc_lm_s.simps[simp del] abc_lm_v.simps[simp del]  
   ci.simps[simp del] t_step.simps[simp del]
   inv_after_move.simps[simp del] 
   inv_on_left_moving_norm.simps[simp del] 
   inv_on_left_moving_in_middle_B.simps[simp del]
   inv_after_clear.simps[simp del] 
   inv_after_write.simps[simp del] inv_on_left_moving.simps[simp del]
   inv_on_right_moving.simps[simp del] 
   inv_check_left_moving.simps[simp del] 
   inv_check_left_moving_in_middle.simps[simp del]
   inv_check_left_moving_on_leftmost.simps[simp del] 
   inv_after_left_moving.simps[simp del]
   inv_stop.simps[simp del] inv_locate_a.simps[simp del] 
   inv_locate_b.simps[simp del]
declare tms_of.simps[simp del] tm_of.simps[simp del]
        layout_of.simps[simp del] abc_fetch.simps [simp del] 
        t_step.simps[simp del] t_steps.simps[simp del] 
        tpairs_of.simps[simp del] start_of.simps[simp del]
        fetch.simps [simp del] new_tape.simps [simp del] 
        nth_of.simps [simp del] ci.simps [simp del]
        length_of.simps[simp del]

(*! Start point *)
lemma [simp]: "Suc (2 * q) mod 2 = Suc 0"
by arith

lemma [simp]: "Suc (2 * q) div 2 = q"
by arith

lemma [simp]: "\<lbrakk> \<not> a < start_of ly as; 
          a < start_of ly as + 2 * n; a - start_of ly as = 2 * q\<rbrakk>
             \<Longrightarrow> Suc a < start_of ly as + 2 * n"
apply(arith)
done

lemma [simp]: "x mod 2 = Suc 0 \<Longrightarrow> (Suc x) mod 2 = 0"
by arith

lemma [simp]: "x mod 2 = Suc 0 \<Longrightarrow> (Suc x) div 2 = Suc (x div 2)"
by arith
lemma exp_def[simp]: "a\<^bsup>Suc n \<^esup>= a # a\<^bsup>n\<^esup>"
by(simp add: exponent_def)
lemma [intro]: "Bk # r = Oc\<^bsup>mr\<^esup> @ r' \<Longrightarrow> mr = 0"
by(case_tac mr, auto simp: exponent_def)

lemma [intro]: "Bk # r = replicate mr Oc \<Longrightarrow> mr = 0"
by(case_tac mr, auto)
lemma tape_of_nl_abv_cons[simp]: "xs \<noteq> [] \<Longrightarrow> 
                   <x # xs> = Oc\<^bsup>Suc x\<^esup>@ Bk # <xs>"
apply(simp add: tape_of_nl_abv tape_of_nat_list.simps)
apply(case_tac xs, simp, simp add: tape_of_nat_list.simps)
done

lemma [simp]: "<[]::nat list> = []"
by(auto simp: tape_of_nl_abv tape_of_nat_list.simps)
lemma [simp]: "Oc # r = <(lm::nat list)> @ Bk\<^bsup>rn\<^esup>\<Longrightarrow> lm \<noteq> []"
apply(auto simp: tape_of_nl_abv tape_of_nat_list.simps)
apply(case_tac rn, auto simp: exponent_def)
done
lemma BkCons_nil: "Bk # xs = <lm::nat list> @ Bk\<^bsup>rn\<^esup>\<Longrightarrow> lm = []"
apply(case_tac lm, simp)
apply(case_tac list, auto simp: tape_of_nl_abv tape_of_nat_list.simps)
done
lemma BkCons_nil': "Bk # xs = <lm::nat list> @ Bk\<^bsup>ln\<^esup>\<Longrightarrow> lm = []"
by(auto intro: BkCons_nil)

lemma hd_tl_tape_of_nat_list:  
   "tl (lm::nat list) \<noteq> [] \<Longrightarrow> <lm> = <hd lm> @ Bk # <tl lm>"
apply(frule tape_of_nl_abv_cons[of "tl lm" "hd lm"])
apply(simp add: tape_of_nat_abv Bk_def del: tape_of_nl_abv_cons)
apply(subgoal_tac "lm = hd lm # tl lm", auto)
apply(case_tac lm, auto)
done
lemma [simp]: "Oc # xs = Oc\<^bsup>mr\<^esup> @ Bk # <lm2> @ Bk\<^bsup>rn\<^esup>\<Longrightarrow> mr > 0"
apply(case_tac mr, auto simp: exponent_def)
done

lemma tape_of_nat_list_cons: "xs \<noteq> [] \<Longrightarrow> tape_of_nat_list (x # xs) =
              replicate (Suc x) Oc @ Bk # tape_of_nat_list xs"
apply(drule tape_of_nl_abv_cons[of xs x])
apply(auto simp: tape_of_nl_abv tape_of_nat_abv Oc_def Bk_def exponent_def)
done

lemma rev_eq: "rev xs = rev ys \<Longrightarrow> xs = ys"
by simp

lemma tape_of_nat_list_eq: " xs = ys \<Longrightarrow> 
        tape_of_nat_list xs = tape_of_nat_list ys"
by simp

lemma tape_of_nl_nil_eq: "<(lm::nat list)> = [] = (lm = [])"
apply(simp add: tape_of_nl_abv tape_of_nat_list.simps)
apply(case_tac lm, simp add: tape_of_nat_list.simps)
apply(case_tac "list")
apply(auto simp: tape_of_nat_list.simps)
done

lemma rep_ind: "replicate (Suc n) a = replicate n a @ [a]"
apply(induct n, simp, simp)
done

lemma [simp]: "Oc # r = <lm::nat list> @ replicate rn Bk \<Longrightarrow> Suc 0 \<le> length lm"
apply(rule_tac classical, auto)
apply(case_tac lm, simp, case_tac rn, auto)
done
lemma Oc_Bk_Cons: "Oc # Bk # list = <lm::nat list> @ Bk\<^bsup>ln\<^esup> \<Longrightarrow> 
                   lm \<noteq> [] \<and> hd lm = 0"
apply(case_tac lm, simp, case_tac ln, simp add: exponent_def, simp add: exponent_def, simp)
apply(case_tac lista, auto simp: tape_of_nl_abv tape_of_nat_list.simps)
done 
(*lemma Oc_Oc_Cons: "Oc # Oc # list = <lm::nat list> @ Bk\<^bsup>ln\<^esup> \<Longrightarrow> 
                  lm \<noteq> [] \<and> hd lm > 0"
apply(case_tac lm, simp add: exponent_def, case_tac ln, simp, simp)
apply(case_tac lista, 
        auto simp: tape_of_nl_abv tape_of_nat_list.simps exponent_def)
apply(case_tac [!] a, auto)
apply(case_tac ln, auto)
done
*)
lemma Oc_nil_zero[simp]: "[Oc] = <lm::nat list> @ Bk\<^bsup>ln\<^esup> 
                 \<Longrightarrow> lm = [0] \<and> ln = 0"
apply(case_tac lm, simp)
apply(case_tac ln, auto simp: exponent_def)
apply(case_tac [!] list, 
        auto simp: tape_of_nl_abv tape_of_nat_list.simps)
done

lemma  [simp]: "Oc # r = <lm2> @ replicate rn Bk \<Longrightarrow> 
       (\<exists>rn. r = replicate (hd lm2) Oc @ Bk # <tl lm2> @ 
                      replicate rn Bk) \<or> 
          tl lm2 = [] \<and> r = replicate (hd lm2) Oc"
apply(rule_tac disjCI, simp)
apply(case_tac "tl lm2 = []", simp)
apply(case_tac lm2, simp add: tape_of_nl_abv tape_of_nat_list.simps)
apply(case_tac rn, simp, simp, simp)
apply(simp add: tape_of_nl_abv tape_of_nat_list.simps exponent_def)
apply(case_tac rn, simp, simp)
apply(rule_tac x = rn in exI)
apply(simp add: hd_tl_tape_of_nat_list)
apply(simp add: tape_of_nat_abv Oc_def exponent_def)
done

(*inv: from locate_a to locate_b*)
lemma [simp]: 
      "inv_locate_a (as, lm) (q, l, Oc # r) ires
       \<Longrightarrow> inv_locate_b (as, lm) (q, Oc # l, r) ires"
apply(simp only: inv_locate_a.simps inv_locate_b.simps in_middle.simps
          at_begin_norm.simps at_begin_fst_bwtn.simps
          at_begin_fst_awtn.simps)
apply(erule disjE, erule exE, erule exE, erule exE)
apply(rule_tac x = lm1 in exI, rule_tac x = "tl lm2" in exI, simp)
apply(rule_tac x = "0" in exI, rule_tac x = "hd lm2" in exI, 
                auto simp: exponent_def)
apply(rule_tac x = "Suc 0" in exI, simp add:exponent_def)
apply(rule_tac x = "lm @ replicate tn 0" in exI, 
      rule_tac x = "[]" in exI,    
      rule_tac x = "Suc tn" in exI, rule_tac x = 0 in exI)
apply(simp only: rep_ind, simp)
apply(rule_tac x = "Suc 0" in exI, auto)
apply(case_tac [1-3] rn, simp_all )
apply(rule_tac x = "lm @ replicate tn 0" in exI, 
      rule_tac x = "[]" in exI, 
      rule_tac x = "Suc tn" in exI, 
      rule_tac x = 0 in exI, simp add: rep_ind del: replicate_Suc split:if_splits)
apply(rule_tac x = "Suc 0" in exI, auto)
apply(case_tac rn, simp, simp)
apply(rule_tac [!] x = "Suc 0" in exI, auto)
apply(case_tac [!] rn, simp_all)
done

(*inv: from locate_a to _locate_a*)
lemma locate_a_2_locate_a[simp]: "inv_locate_a (as, am) (q, aaa, Bk # xs) ires
       \<Longrightarrow> inv_locate_a (as, am) (q, aaa, Oc # xs) ires"
apply(simp only: inv_locate_a.simps at_begin_norm.simps 
                 at_begin_fst_bwtn.simps at_begin_fst_awtn.simps)
apply(erule_tac disjE, erule exE, erule exE, erule exE, 
      rule disjI2, rule disjI2)
defer
apply(erule_tac disjE, erule exE, erule exE, 
      erule exE, rule disjI2, rule disjI2)
prefer 2
apply(simp)
proof-
  fix lm1 tn rn
  assume k: "lm1 = am @ 0\<^bsup>tn\<^esup> \<and> length lm1 = q \<and> (if lm1 = [] then aaa = Bk # Bk # 
    ires else aaa = [Bk] @ <rev lm1> @ Bk # Bk # ires) \<and> Bk # xs = Bk\<^bsup>rn\<^esup>"
  thus "\<exists>lm1 tn rn. lm1 = am @ 0\<^bsup>tn\<^esup> \<and> length lm1 = q \<and> (if lm1 = [] then 
    aaa = Bk # Bk # ires else aaa = [Bk] @ <rev lm1> @ Bk # Bk # ires) \<and> Oc # xs = [Oc] @ Bk\<^bsup>rn\<^esup>"
    (is "\<exists>lm1 tn rn. ?P lm1 tn rn")
  proof -
    from k have "?P lm1 tn (rn - 1)"
      apply(auto simp: Oc_def)
      by(case_tac [!] "rn::nat", auto simp: exponent_def)
    thus ?thesis by blast
  qed
next
  fix lm1 lm2 rn
  assume h1: "am = lm1 @ lm2 \<and> length lm1 = q \<and> (if lm1 = [] 
    then aaa = Bk # Bk # ires else aaa = Bk # <rev lm1> @ Bk # Bk # ires) \<and>
    Bk # xs = <lm2> @ Bk\<^bsup>rn\<^esup>"
  from h1 have h2: "lm2 = []"
  proof(rule_tac xs = xs and rn = rn in BkCons_nil, simp)
  qed
  from h1 and h2 show "\<exists>lm1 tn rn. lm1 = am @ 0\<^bsup>tn\<^esup> \<and> length lm1 = q \<and> 
    (if lm1 = [] then aaa = Bk # Bk # ires else aaa = [Bk] @ <rev lm1> @ Bk # Bk # ires) \<and>
    Oc # xs = [Oc] @ Bk\<^bsup>rn\<^esup>" 
    (is "\<exists>lm1 tn rn. ?P lm1 tn rn")
  proof -
    from h1 and h2  have "?P lm1 0 (rn - 1)"
      apply(auto simp: Oc_def exponent_def 
                      tape_of_nl_abv tape_of_nat_list.simps)
      by(case_tac "rn::nat", simp, simp)
    thus ?thesis by blast
  qed
qed

lemma [intro]: "\<exists>rn. [a] = a\<^bsup>rn\<^esup>"
by(rule_tac x = "Suc 0" in exI, simp add: exponent_def)

lemma [intro]: "\<exists>tn. [] = a\<^bsup>tn\<^esup>"
apply(rule_tac x = 0 in exI, simp add: exponent_def)
done

lemma [intro]:  "at_begin_norm (as, am) (q, aaa, []) ires
             \<Longrightarrow> at_begin_norm (as, am) (q, aaa, [Bk]) ires"
apply(simp add: at_begin_norm.simps, erule_tac exE, erule_tac exE)
apply(rule_tac x = lm1 in exI, simp, auto)
done

lemma [intro]: "at_begin_fst_bwtn (as, am) (q, aaa, []) ires 
            \<Longrightarrow> at_begin_fst_bwtn (as, am) (q, aaa, [Bk]) ires"
apply(simp only: at_begin_fst_bwtn.simps, erule_tac exE, erule_tac exE, erule_tac exE)
apply(rule_tac x = "am @ 0\<^bsup>tn\<^esup>" in exI, auto)
done

lemma [intro]: "at_begin_fst_awtn (as, am) (q, aaa, []) ires
           \<Longrightarrow> at_begin_fst_awtn (as, am) (q, aaa, [Bk]) ires"
apply(auto simp: at_begin_fst_awtn.simps)
done 

lemma [intro]: "inv_locate_a (as, am) (q, aaa, []) ires
            \<Longrightarrow> inv_locate_a (as, am) (q, aaa, [Bk]) ires"
apply(simp only: inv_locate_a.simps)
apply(erule disj_forward)
defer
apply(erule disj_forward, auto)
done

lemma [simp]: "inv_locate_a (as, am) (q, aaa, []) ires \<Longrightarrow> 
               inv_locate_a (as, am) (q, aaa, [Oc]) ires"
apply(insert locate_a_2_locate_a [of as am q aaa "[]"])
apply(subgoal_tac "inv_locate_a (as, am) (q, aaa, [Bk]) ires", auto)
done

(*inv: from locate_b to locate_b*)
lemma [simp]: "inv_locate_b (as, am) (q, aaa, Oc # xs) ires
         \<Longrightarrow> inv_locate_b (as, am) (q, Oc # aaa, xs) ires"
apply(simp only: inv_locate_b.simps in_middle.simps)
apply(erule exE)+
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = tn in exI, rule_tac x = m in exI)
apply(rule_tac x = "Suc ml" in exI, rule_tac x = "mr - 1" in exI,
      rule_tac x = rn in exI)
apply(case_tac mr, simp_all add: exponent_def, auto)
done
lemma zero_and_nil[intro]: "(Bk # Bk\<^bsup>n\<^esup> = Oc\<^bsup>mr\<^esup> @ Bk # <lm::nat list> @ 
                             Bk\<^bsup>rn \<^esup>) \<or> (lm2 = [] \<and> Bk # Bk\<^bsup>n\<^esup> = Oc\<^bsup>mr\<^esup>)
       \<Longrightarrow> mr = 0 \<and> lm = []"
apply(rule context_conjI)
apply(case_tac mr, auto simp:exponent_def)
apply(insert BkCons_nil[of "replicate (n - 1) Bk" lm rn])
apply(case_tac n, auto simp: exponent_def Bk_def  tape_of_nl_nil_eq)
done

lemma tape_of_nat_def: "<[m::nat]> =  Oc # Oc\<^bsup>m\<^esup>"
apply(simp add: tape_of_nl_abv tape_of_nat_list.simps)
done
lemma [simp]: "\<lbrakk>inv_locate_b (as, am) (q, aaa, Bk # xs) ires; \<exists>n. xs = Bk\<^bsup>n\<^esup>\<rbrakk>
            \<Longrightarrow> inv_locate_a (as, am) (Suc q, Bk # aaa, xs) ires"
apply(simp add: inv_locate_b.simps inv_locate_a.simps)
apply(rule_tac disjI2, rule_tac disjI1)
apply(simp only: in_middle.simps at_begin_fst_bwtn.simps)
apply(erule_tac exE)+
apply(rule_tac x = "lm1 @ [m]" in exI, rule_tac x = tn in exI, simp)
apply(subgoal_tac "mr = 0 \<and> lm2 = []")
defer
apply(rule_tac n = n and mr = mr and lm = "lm2" 
               and rn = rn and n = n in zero_and_nil)
apply(auto simp: exponent_def)
apply(case_tac "lm1 = []", auto simp: tape_of_nat_def)
done

lemma length_equal: "xs = ys \<Longrightarrow> length xs = length ys"
by auto
lemma [simp]: "a\<^bsup>0\<^esup> = []" 
by(simp add: exp_zero)
(*inv: from locate_b to locate_a*)
lemma [simp]: "length (a\<^bsup>b\<^esup>) = b"
apply(simp add: exponent_def)
done

lemma [simp]: "\<lbrakk>inv_locate_b (as, am) (q, aaa, Bk # xs) ires; 
                \<not> (\<exists>n. xs = Bk\<^bsup>n\<^esup>)\<rbrakk> 
       \<Longrightarrow> inv_locate_a (as, am) (Suc q, Bk # aaa, xs) ires"
apply(simp add: inv_locate_b.simps inv_locate_a.simps)
apply(rule_tac disjI1)
apply(simp only: in_middle.simps at_begin_norm.simps)
apply(erule_tac exE)+
apply(rule_tac x = "lm1 @ [m]" in exI, rule_tac x = lm2 in exI, simp)
apply(subgoal_tac "tn = 0", simp add: exponent_def , auto split: if_splits)
apply(case_tac [!] mr, simp_all add: tape_of_nat_def, auto)
apply(case_tac lm2, simp, erule_tac x = rn in allE, simp)
apply(case_tac am, simp, simp)
apply(case_tac lm2, simp, erule_tac x = rn in allE, simp)
apply(drule_tac length_equal, simp)
done

lemma locate_b_2_a[intro]: 
       "inv_locate_b (as, am) (q, aaa, Bk # xs) ires
    \<Longrightarrow> inv_locate_a (as, am) (Suc q, Bk # aaa, xs) ires"
apply(case_tac "\<exists> n. xs = Bk\<^bsup>n\<^esup>", simp, simp)
done

lemma locate_b_2_locate_a[simp]: 
    "\<lbrakk>\<not> a < start_of ly as; 
      a < start_of ly as + 2 * n; 
      (a - start_of ly as) mod 2 = Suc 0; 
     inv_locate_b (as, am) ((a - start_of ly as) div 2, aaa, Bk # xs) ires\<rbrakk>
   \<Longrightarrow> (Suc a < start_of ly as + 2 * n \<longrightarrow> inv_locate_a (as, am)
       (Suc ((a - start_of ly as) div 2), Bk # aaa, xs) ires) \<and>
       (\<not> Suc a < start_of ly as + 2 * n \<longrightarrow> 
                inv_locate_a (as, am) (n, Bk # aaa, xs) ires)"
apply(auto)
apply(subgoal_tac "n > 0")
apply(subgoal_tac "(a - start_of ly as) div 2 = n - 1")
apply(insert locate_b_2_a [of as am "n - 1" aaa xs], simp)
apply(arith)
apply(case_tac n, simp, simp)
done

lemma [simp]:  "inv_locate_b (as, am) (q, l, []) ires 
           \<Longrightarrow>  inv_locate_b (as, am) (q, l, [Bk]) ires"
apply(simp only: inv_locate_b.simps in_middle.simps)
apply(erule exE)+
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = tn in exI, rule_tac x = m in exI, 
      rule_tac x = ml in exI, rule_tac x = mr in exI)
apply(auto)
done

lemma locate_b_2_locate_a_B[simp]: 
 "\<lbrakk>\<not> a < start_of ly as; 
   a < start_of ly as + 2 * n; 
   (a - start_of ly as) mod 2 = Suc 0; 
   inv_locate_b (as, am) ((a - start_of ly as) div 2, aaa, []) ires\<rbrakk>
   \<Longrightarrow> (Suc a < start_of ly as + 2 * n \<longrightarrow> 
     inv_locate_a (as, am) 
            (Suc ((a - start_of ly as) div 2), Bk # aaa, []) ires) 
    \<and> (\<not> Suc a < start_of ly as + 2 * n \<longrightarrow> 
                  inv_locate_a (as, am) (n, Bk # aaa, []) ires)"
apply(insert locate_b_2_locate_a [of a ly as n am aaa "[]"], simp)
done

(*inv: from locate_b to after_write*)
lemma inv_locate_b_2_after_write[simp]: 
      "inv_locate_b (as, am) (n, aaa, Bk # xs) ires
      \<Longrightarrow> inv_after_write (as, abc_lm_s am n (Suc (abc_lm_v am n)))
          (Suc (Suc (2 * n)), aaa, Oc # xs) ires"
apply(auto simp: in_middle.simps inv_after_write.simps 
                 abc_lm_v.simps abc_lm_s.simps  inv_locate_b.simps)
apply(subgoal_tac [!] "mr = 0", auto simp: exponent_def split: if_splits)
apply(subgoal_tac "lm2 = []", simp)
apply(rule_tac x = rn in exI, rule_tac x = "Suc m" in exI,
      rule_tac x = "lm1" in exI, simp, rule_tac x = "[]" in exI, simp)
apply(case_tac "Suc (length lm1) - length am", simp, simp only: rep_ind, simp)
apply(subgoal_tac "length lm1 - length am = nat", simp, arith)
apply(drule_tac length_equal, simp)
done

lemma [simp]: "inv_locate_b (as, am) (n, aaa, []) ires \<Longrightarrow> 
     inv_after_write (as, abc_lm_s am n (Suc (abc_lm_v am n))) 
                     (Suc (Suc (2 * n)), aaa, [Oc]) ires"
apply(insert inv_locate_b_2_after_write [of as am n aaa "[]"])
by(simp)

(*inv: from after_write to after_move*)
lemma [simp]: "inv_after_write (as, lm) (Suc (Suc (2 * n)), l, Oc # r) ires
                \<Longrightarrow> inv_after_move (as, lm) (2 * n + 3, Oc # l, r) ires"
apply(auto simp:inv_after_move.simps inv_after_write.simps split: if_splits)
done

lemma [simp]: "inv_after_write (as, abc_lm_s am n (Suc (abc_lm_v am n)
                )) (Suc (Suc (2 * n)), aaa, Bk # xs) ires = False"
apply(simp add: inv_after_write.simps )
done

lemma [simp]: 
 "inv_after_write (as, abc_lm_s am n (Suc (abc_lm_v am n))) 
                        (Suc (Suc (2 * n)), aaa, []) ires = False"
apply(simp add: inv_after_write.simps )
done

(*inv: from after_move to after_clear*)
lemma [simp]: "inv_after_move (as, lm) (s, l, Oc # r) ires
                \<Longrightarrow> inv_after_clear (as, lm) (s', l, Bk # r) ires"
apply(auto simp: inv_after_move.simps inv_after_clear.simps split: if_splits)
done

(*inv: from after_move to on_leftmoving*)
lemma inv_after_move_2_inv_on_left_moving[simp]:  
   "inv_after_move (as, lm) (s, l, Bk # r) ires
   \<Longrightarrow> (l = [] \<longrightarrow> 
         inv_on_left_moving (as, lm) (s', [], Bk # Bk # r) ires) \<and>
      (l \<noteq> [] \<longrightarrow> 
         inv_on_left_moving (as, lm) (s', tl l, hd l # Bk # r) ires)"
apply(simp only: inv_after_move.simps inv_on_left_moving.simps)
apply(subgoal_tac "l \<noteq> []", rule conjI, simp, rule impI, 
                rule disjI1, simp only: inv_on_left_moving_norm.simps)
apply(erule exE)+
apply(subgoal_tac "lm2 = []")
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI,  
    rule_tac x = m in exI, rule_tac x = m in exI, 
    rule_tac x = 1 in exI,  
    rule_tac x = "rn - 1" in exI, simp, case_tac rn)
apply(auto simp: exponent_def  intro: BkCons_nil split: if_splits)
done

lemma [elim]: "[] = <lm::nat list> \<Longrightarrow> lm = []"
using tape_of_nl_nil_eq[of lm]
by simp

lemma inv_after_move_2_inv_on_left_moving_B[simp]: 
    "inv_after_move (as, lm) (s, l, []) ires
      \<Longrightarrow> (l = [] \<longrightarrow> inv_on_left_moving (as, lm) (s', [], [Bk]) ires) \<and>
          (l \<noteq> [] \<longrightarrow> inv_on_left_moving (as, lm) (s', tl l, [hd l]) ires)"
apply(simp only: inv_after_move.simps inv_on_left_moving.simps)
apply(subgoal_tac "l \<noteq> []", rule conjI, simp, rule impI, rule disjI1,
        simp only: inv_on_left_moving_norm.simps)
apply(erule exE)+
apply(subgoal_tac "lm2 = []")
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI,  
      rule_tac x = m in exI, rule_tac x = m in exI, 
      rule_tac x = 1 in exI, rule_tac x = "rn - 1" in exI, simp, case_tac rn)
apply(auto simp: exponent_def  tape_of_nl_nil_eq  intro: BkCons_nil  split: if_splits)
done

(*inv: from after_clear to on_right_moving*)
lemma [simp]: "Oc # r = replicate rn Bk = False"
apply(case_tac rn, simp, simp)
done

lemma inv_after_clear_2_inv_on_right_moving[simp]: 
     "inv_after_clear (as, lm) (2 * n + 4, l, Bk # r) ires
      \<Longrightarrow> inv_on_right_moving (as, lm) (2 * n + 5, Bk # l, r) ires"
apply(auto simp: inv_after_clear.simps inv_on_right_moving.simps )
apply(subgoal_tac "lm2 \<noteq> []")
apply(rule_tac x = "lm1 @ [m]" in exI, rule_tac x = "tl lm2" in exI, 
      rule_tac x = "hd lm2" in exI, simp)
apply(rule_tac x = 0 in exI, rule_tac x = "hd lm2" in exI)
apply(simp add: exponent_def, rule conjI)
apply(case_tac [!] "lm2::nat list", auto simp: exponent_def)
apply(case_tac rn, auto split: if_splits simp: tape_of_nat_def)
apply(case_tac list, 
     simp add:  tape_of_nl_abv tape_of_nat_list.simps exponent_def)
apply(erule_tac x = "rn - 1" in allE, 
      case_tac rn, auto simp: exponent_def)
apply(case_tac list, 
     simp add:  tape_of_nl_abv tape_of_nat_list.simps exponent_def)
apply(erule_tac x = "rn - 1" in allE, 
      case_tac rn, auto simp: exponent_def)
done


lemma [simp]: "inv_after_clear (as, lm) (2 * n + 4, l, []) ires\<Longrightarrow> 
               inv_after_clear (as, lm) (2 * n + 4, l, [Bk]) ires" 
by(auto simp: inv_after_clear.simps)

lemma [simp]: "inv_after_clear (as, lm) (2 * n + 4, l, []) ires
             \<Longrightarrow> inv_on_right_moving (as, lm) (2 * n + 5, Bk # l, []) ires"
by(insert 
    inv_after_clear_2_inv_on_right_moving[of as lm n l "[]"], simp)

(*inv: from on_right_moving to on_right_movign*)
lemma [simp]: "inv_on_right_moving (as, lm) (2 * n + 5, l, Oc # r) ires
      \<Longrightarrow> inv_on_right_moving (as, lm) (2 * n + 5, Oc # l, r) ires"
apply(auto simp: inv_on_right_moving.simps)
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
           rule_tac x = "ml + mr" in exI, simp)
apply(rule_tac x = "Suc ml" in exI, 
           rule_tac x = "mr - 1" in exI, simp)
apply(case_tac mr, auto simp: exponent_def )
apply(rule_tac x = lm1 in exI, rule_tac x = "[]" in exI, 
      rule_tac x = "ml + mr" in exI, simp)
apply(rule_tac x = "Suc ml" in exI, 
      rule_tac x = "mr - 1" in exI, simp)
apply(case_tac mr, auto split: if_splits simp: exponent_def)
done

lemma inv_on_right_moving_2_inv_on_right_moving[simp]: 
     "inv_on_right_moving (as, lm) (2 * n + 5, l, Bk # r) ires
     \<Longrightarrow> inv_after_write (as, lm) (Suc (Suc (2 * n)), l, Oc # r) ires"
apply(auto simp: inv_on_right_moving.simps inv_after_write.simps )
apply(case_tac mr, auto simp: exponent_def split: if_splits)
apply(case_tac [!] mr, simp_all)
done
      
lemma [simp]: "inv_on_right_moving (as, lm) (2 * n + 5, l, []) ires\<Longrightarrow> 
             inv_on_right_moving (as, lm) (2 * n + 5, l, [Bk]) ires"
apply(auto simp: inv_on_right_moving.simps exponent_def)
apply(rule_tac x = lm1 in exI, rule_tac x = "[]" in exI, simp)
apply (rule_tac x = m in exI, auto split: if_splits simp: exponent_def)
done

(*inv: from on_right_moving to after_write*)
lemma [simp]: "inv_on_right_moving (as, lm) (2 * n + 5, l, []) ires
       \<Longrightarrow> inv_after_write (as, lm) (Suc (Suc (2 * n)), l, [Oc]) ires"
apply(rule_tac inv_on_right_moving_2_inv_on_right_moving, simp)
done

(*inv: from on_left_moving to on_left_moving*)
lemma [simp]: "inv_on_left_moving_in_middle_B (as, lm) 
               (s, l, Oc # r) ires = False"
apply(auto simp: inv_on_left_moving_in_middle_B.simps )
done

lemma [simp]: "inv_on_left_moving_norm (as, lm) (s, l, Bk # r) ires 
             = False"
apply(auto simp: inv_on_left_moving_norm.simps)
apply(case_tac [!] mr, auto simp: )
done

lemma [intro]: "\<exists>rna. Oc # Oc\<^bsup>m\<^esup> @ Bk # <lm> @ Bk\<^bsup>rn\<^esup> = <m # lm> @ Bk\<^bsup>rna\<^esup>"
apply(case_tac lm, simp add: tape_of_nl_abv tape_of_nat_list.simps)
apply(rule_tac x = "Suc rn" in exI, simp)
apply(case_tac list, simp_all add: tape_of_nl_abv tape_of_nat_list.simps, auto)
done


lemma [simp]: 
  "\<lbrakk>inv_on_left_moving_norm (as, lm) (s, l, Oc # r) ires;
    hd l = Bk; l \<noteq> []\<rbrakk> \<Longrightarrow> 
     inv_on_left_moving_in_middle_B (as, lm) (s, tl l, Bk # Oc # r) ires"
apply(case_tac l, simp, simp)
apply(simp only: inv_on_left_moving_norm.simps 
                 inv_on_left_moving_in_middle_B.simps)
apply(erule_tac exE)+
apply(rule_tac x = lm1 in exI, rule_tac x = "m # lm2" in exI, auto)
apply(case_tac [!] ml, auto)
apply(rule_tac [!] x = 0 in exI, simp_all add: tape_of_nl_abv tape_of_nat_list.simps)
done

lemma [simp]: "\<lbrakk>inv_on_left_moving_norm (as, lm) (s, l, Oc # r) ires; 
                hd l = Oc; l \<noteq> []\<rbrakk>
            \<Longrightarrow> inv_on_left_moving_norm (as, lm) 
                                        (s, tl l, Oc # Oc # r) ires"
apply(simp only: inv_on_left_moving_norm.simps)
apply(erule exE)+
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = m in exI, rule_tac x = "ml - 1" in exI,
      rule_tac x = "Suc mr" in exI, rule_tac x = rn in exI, simp)
apply(case_tac ml, auto simp: exponent_def split: if_splits)
done

lemma [simp]: "inv_on_left_moving_norm (as, lm) (s, [], Oc # r) ires
     \<Longrightarrow> inv_on_left_moving_in_middle_B (as, lm) (s, [], Bk # Oc # r) ires"
apply(auto simp: inv_on_left_moving_norm.simps 
                 inv_on_left_moving_in_middle_B.simps split: if_splits)
done

lemma [simp]:"inv_on_left_moving (as, lm) (s, l, Oc # r) ires
    \<Longrightarrow> (l = [] \<longrightarrow> inv_on_left_moving (as, lm) (s, [], Bk # Oc # r) ires)
 \<and>  (l \<noteq> [] \<longrightarrow> inv_on_left_moving (as, lm) (s, tl l, hd l # Oc # r) ires)"
apply(simp add: inv_on_left_moving.simps)
apply(case_tac "l \<noteq> []", rule conjI, simp, simp)
apply(case_tac "hd l", simp, simp, simp)
done

(*inv: from on_left_moving to check_left_moving*)
lemma [simp]: "inv_on_left_moving_in_middle_B (as, lm) 
                                      (s, Bk # list, Bk # r) ires
          \<Longrightarrow> inv_check_left_moving_on_leftmost (as, lm) 
                                      (s', list, Bk # Bk # r) ires"
apply(auto simp: inv_on_left_moving_in_middle_B.simps 
                 inv_check_left_moving_on_leftmost.simps split: if_splits)
apply(case_tac [!] "rev lm1", simp_all)
apply(case_tac [!] lista, simp_all add: tape_of_nl_abv tape_of_nat_list.simps)
done

lemma [simp]:
    "inv_check_left_moving_in_middle (as, lm) (s, l, Bk # r) ires= False"
by(auto simp: inv_check_left_moving_in_middle.simps )

lemma [simp]: 
 "inv_on_left_moving_in_middle_B (as, lm) (s, [], Bk # r) ires\<Longrightarrow> 
  inv_check_left_moving_on_leftmost (as, lm) (s', [], Bk # Bk # r) ires"
apply(auto simp: inv_on_left_moving_in_middle_B.simps 
                 inv_check_left_moving_on_leftmost.simps split: if_splits)
done


lemma [simp]: "inv_check_left_moving_on_leftmost (as, lm) 
                                       (s, list, Oc # r) ires= False"
by(auto simp: inv_check_left_moving_on_leftmost.simps split: if_splits)

lemma [simp]: "inv_on_left_moving_in_middle_B (as, lm) 
                                         (s, Oc # list, Bk # r) ires
 \<Longrightarrow> inv_check_left_moving_in_middle (as, lm) (s', list, Oc # Bk # r) ires"
apply(auto simp: inv_on_left_moving_in_middle_B.simps 
                 inv_check_left_moving_in_middle.simps  split: if_splits)
done

lemma inv_on_left_moving_2_check_left_moving[simp]:
 "inv_on_left_moving (as, lm) (s, l, Bk # r) ires
 \<Longrightarrow> (l = [] \<longrightarrow> inv_check_left_moving (as, lm) (s', [], Bk # Bk # r) ires)
 \<and> (l \<noteq> [] \<longrightarrow> 
      inv_check_left_moving (as, lm) (s', tl l, hd l # Bk # r) ires)"
apply(simp add: inv_on_left_moving.simps inv_check_left_moving.simps)
apply(case_tac l, simp, simp)
apply(case_tac a, simp, simp)
done

lemma [simp]: "inv_on_left_moving_norm (as, lm) (s, l, []) ires = False"
apply(auto simp: inv_on_left_moving_norm.simps)
by(case_tac [!] mr, auto)

lemma [simp]: "inv_on_left_moving (as, lm) (s, l, []) ires\<Longrightarrow> 
     inv_on_left_moving (as, lm) (6 + 2 * n, l, [Bk]) ires"
apply(simp add: inv_on_left_moving.simps)
apply(auto simp: inv_on_left_moving_in_middle_B.simps)
done

lemma [simp]: "inv_on_left_moving (as, lm) (s, l, []) ires = False"
apply(simp add: inv_on_left_moving.simps)
apply(simp add: inv_on_left_moving_in_middle_B.simps)
done

lemma [simp]: "inv_on_left_moving (as, lm) (s, l, []) ires
 \<Longrightarrow> (l = [] \<longrightarrow> inv_check_left_moving (as, lm) (s', [], [Bk]) ires) \<and>
    (l \<noteq> [] \<longrightarrow> inv_check_left_moving (as, lm) (s', tl l, [hd l]) ires)"
by simp

lemma Oc_Bk_Cons_ex[simp]: 
 "Oc # Bk # list = <lm::nat list> @ Bk\<^bsup>ln\<^esup> \<Longrightarrow> 
                             \<exists>ln. list = <tl (lm)> @ Bk\<^bsup>ln\<^esup>"
apply(case_tac "lm", simp)
apply(case_tac ln, simp_all add: exponent_def)
apply(case_tac lista, 
      auto simp: tape_of_nl_abv tape_of_nat_list.simps exponent_def)
apply(case_tac [!] a, auto simp: )
apply(case_tac ln, simp, rule_tac x = nat in exI, simp)
done

lemma [simp]:
  "Oc # Bk # list = <rev lm1::nat list> @ Bk\<^bsup>ln\<^esup> \<Longrightarrow> 
      \<exists>rna. Oc # Bk # <lm2> @ Bk\<^bsup>rn\<^esup> = <hd (rev lm1) # lm2> @ Bk\<^bsup>rna\<^esup>"
apply(frule Oc_Bk_Cons, simp)
apply(case_tac lm2, 
     auto simp: tape_of_nl_abv tape_of_nat_list.simps  exponent_def )
apply(rule_tac x = "Suc rn" in exI, simp)
done

(*inv: from check_left_moving to on_left_moving*)
lemma [intro]: "\<exists>rna. a # a\<^bsup>rn\<^esup> = a\<^bsup>rna\<^esup>"
apply(rule_tac x = "Suc rn" in exI, simp)
done

lemma 
inv_check_left_moving_in_middle_2_on_left_moving_in_middle_B[simp]:
"inv_check_left_moving_in_middle (as, lm) (s, Bk # list, Oc # r) ires
  \<Longrightarrow> inv_on_left_moving_in_middle_B (as, lm) (s', list, Bk # Oc # r) ires"
apply(simp only: inv_check_left_moving_in_middle.simps 
                 inv_on_left_moving_in_middle_B.simps)
apply(erule_tac exE)+
apply(rule_tac x = "rev (tl (rev lm1))" in exI, 
      rule_tac x = "[hd (rev lm1)] @ lm2" in exI, auto)
apply(case_tac [!] "rev lm1",simp_all add: tape_of_nl_abv tape_of_nat_list.simps)
apply(case_tac [!] a, simp_all)
apply(case_tac [1] lm2, simp_all add: tape_of_nat_list.simps, auto)
apply(case_tac [3] lm2, simp_all add: tape_of_nat_list.simps, auto)
apply(case_tac [!] lista, simp_all add: tape_of_nat_list.simps)
done

lemma [simp]: 
 "inv_check_left_moving_in_middle (as, lm) (s, [], Oc # r) ires\<Longrightarrow>
     inv_check_left_moving_in_middle (as, lm) (s', [Bk], Oc # r) ires"
apply(auto simp: inv_check_left_moving_in_middle.simps )
done

lemma [simp]: 
 "inv_check_left_moving_in_middle (as, lm) (s, [], Oc # r) ires
   \<Longrightarrow> inv_on_left_moving_in_middle_B (as, lm) (s', [], Bk # Oc # r) ires"
apply(insert 
inv_check_left_moving_in_middle_2_on_left_moving_in_middle_B[of 
                  as lm n "[]" r], simp)
done 

lemma [simp]: "a\<^bsup>0\<^esup> = []"
apply(simp add: exponent_def)
done

lemma [simp]: "inv_check_left_moving_in_middle (as, lm) 
                       (s, Oc # list, Oc # r) ires
   \<Longrightarrow> inv_on_left_moving_norm (as, lm) (s', list, Oc # Oc # r) ires"
apply(auto simp: inv_check_left_moving_in_middle.simps 
                 inv_on_left_moving_norm.simps)
apply(rule_tac x = "rev (tl (rev lm1))" in exI, 
      rule_tac x = lm2 in exI, rule_tac x = "hd (rev lm1)" in exI)
apply(rule_tac conjI)
apply(case_tac "rev lm1", simp, simp)
apply(rule_tac x = "hd (rev lm1) - 1" in exI, auto)
apply(rule_tac [!] x = "Suc (Suc 0)" in exI, simp)
apply(case_tac [!] "rev lm1", simp_all)
apply(case_tac [!] a, simp_all add: tape_of_nl_abv tape_of_nat_list.simps, auto)
done 

lemma [simp]: "inv_check_left_moving (as, lm) (s, l, Oc # r) ires
\<Longrightarrow> (l = [] \<longrightarrow> inv_on_left_moving (as, lm) (s', [], Bk # Oc # r) ires) \<and>
   (l \<noteq> [] \<longrightarrow> inv_on_left_moving (as, lm) (s', tl l, hd l # Oc # r) ires)"
apply(case_tac l, 
      auto simp: inv_check_left_moving.simps inv_on_left_moving.simps)
apply(case_tac a, simp, simp)
done

(*inv: check_left_moving to after_left_moving*)
lemma [simp]: "inv_check_left_moving (as, lm) (s, l, Bk # r) ires
                \<Longrightarrow> inv_after_left_moving (as, lm) (s', Bk # l, r) ires"
apply(auto simp: inv_check_left_moving.simps 
 inv_check_left_moving_on_leftmost.simps inv_after_left_moving.simps)
done


lemma [simp]:"inv_check_left_moving (as, lm) (s, l, []) ires
      \<Longrightarrow> inv_after_left_moving (as, lm) (s', Bk # l, []) ires"
by(simp add: inv_check_left_moving.simps  
inv_check_left_moving_in_middle.simps 
inv_check_left_moving_on_leftmost.simps)

(*inv: after_left_moving to inv_stop*)
lemma [simp]: "inv_after_left_moving (as, lm) (s, l, Bk # r) ires
       \<Longrightarrow> inv_stop (as, lm) (s', Bk # l, r) ires"
apply(auto simp: inv_after_left_moving.simps inv_stop.simps)
done

lemma [simp]: "inv_after_left_moving (as, lm) (s, l, []) ires
             \<Longrightarrow> inv_stop (as, lm) (s', Bk # l, []) ires"
by(auto simp: inv_after_left_moving.simps)

(*inv: stop to stop*)
lemma [simp]: "inv_stop (as, lm) (x, l, r) ires \<Longrightarrow> 
               inv_stop (as, lm) (y, l, r) ires"
apply(simp add: inv_stop.simps)
done

lemma [simp]: "inv_after_clear (as, lm) (s, aaa, Oc # xs) ires= False"
apply(auto simp: inv_after_clear.simps )
done

lemma [simp]: 
  "inv_after_left_moving (as, lm) (s, aaa, Oc # xs) ires = False"
by(auto simp: inv_after_left_moving.simps  )

lemma start_of_not0: "as \<noteq> 0 \<Longrightarrow> start_of ly as > 0"
apply(rule startof_not0)
done

text {*
  The single step currectness of the TM complied from Abacus instruction @{text "Inc n"}.
  It shows every single step execution of this TM keeps the invariant.
*}

lemma inc_inv_step: 
  assumes 
  -- {* Invariant holds on the start *}
      h11: "inc_inv ly n (as, am) tc ires" 
  -- {* The layout of Abacus program @{text "aprog"} is @{text "ly"} *}
  and h12: "ly = layout_of aprog" 
  -- {* The instruction at position @{text "as"} is @{text "Inc n"} *}
  and h21: "abc_fetch as aprog = Some (Inc n)" 
  -- {* TM not yet reach the final state, where @{text "start_of ly as + 2*n + 9"} is the state
        where the current TM stops and the next TM starts. *}
  and h22: "(\<lambda> (s, l, r). s \<noteq> start_of ly as + 2*n + 9) tc"
  shows 
  -- {* 
  Single step execution of the TM keeps the invaraint, where 
  the TM compiled from @{text "Inc n"} is @{text "(ci ly (start_of ly as) (Inc n))"}
  @{text "start_of ly as - Suc 0)"} is the offset used to execute this {\em shifted}
  TM.
  *}
  "inc_inv ly n (as, am) (t_step tc (ci ly (start_of ly as) (Inc n), start_of ly as - Suc 0)) ires"
proof -
  from h21 h22  have h3 : "start_of (layout_of aprog) as > 0"
    apply(case_tac as, simp add: start_of.simps abc_fetch.simps)
    apply(insert start_of_not0[of as "layout_of aprog"], simp)
    done    
  from h11 h12 and h21 h22 and this show ?thesis 
    apply(case_tac tc, simp)
    apply(case_tac "a = 0", 
      auto split:if_splits simp add:t_step.simps,
      tactic {* ALLGOALS (resolve_tac [@{thm fetch_intro}]) *})
    apply (simp_all add:fetch_simps new_tape.simps)
    done
qed


lemma t_steps_ind: "t_steps tc (p, off) (Suc n)
                 = t_step (t_steps tc (p, off) n) (p, off)"
apply(induct n arbitrary: tc)
apply(simp add: t_steps.simps)
apply(simp add: t_steps.simps)
done

definition lex_pair :: "((nat \<times> nat) \<times> (nat \<times> nat)) set"
  where 
  "lex_pair \<equiv> less_than <*lex*> less_than"

definition lex_triple :: 
   "((nat \<times> (nat \<times> nat)) \<times> (nat \<times> (nat \<times> nat))) set"
  where "lex_triple \<equiv> less_than <*lex*> lex_pair"

definition lex_square :: 
    "((nat \<times> nat \<times> nat \<times> nat) \<times> (nat \<times> nat \<times> nat \<times> nat)) set"
  where "lex_square \<equiv> less_than <*lex*> lex_triple"

fun abc_inc_stage1 :: "t_conf \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> nat"
  where
  "abc_inc_stage1 (s, l, r) ss n = 
            (if s = 0 then 0
             else if s \<le> ss+2*n+1 then 5
             else if s\<le> ss+2*n+5 then 4
             else if s \<le> ss+2*n+7 then 3
             else if s = ss+2*n+8 then 2
             else 1)"

fun abc_inc_stage2 :: "t_conf \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> nat"
  where
  "abc_inc_stage2 (s, l, r) ss n =
                (if s \<le> ss + 2*n + 1 then 0
                 else if s = ss + 2*n + 2 then length r
                 else if s = ss + 2*n + 3 then length r
                 else if s = ss + 2*n + 4 then length r
                 else if s = ss + 2*n + 5 then 
                                  if r \<noteq> [] then length r
                                  else 1
                 else if s = ss+2*n+6 then length l
                 else if s = ss+2*n+7 then length l
                 else 0)"

fun abc_inc_stage3 :: "t_conf \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> block list \<Rightarrow>  nat"
  where
  "abc_inc_stage3 (s, l, r) ss n ires = (
              if s = ss + 2*n + 3 then 4
              else if s = ss + 2*n + 4 then 3
              else if s = ss + 2*n + 5 then 
                   if r \<noteq> [] \<and> hd r = Oc then 2
                   else 1
              else if s = ss + 2*n + 2 then 0
              else if s = ss + 2*n + 6 then 
                      if l = Bk # ires \<and> r \<noteq> [] \<and>  hd r = Oc then 2
                      else 1
              else if s = ss + 2*n + 7 then 
                      if r \<noteq> [] \<and> hd r = Oc then 3
                      else 0
              else ss+2*n+9 - s)"

fun abc_inc_stage4 :: "t_conf \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> block list \<Rightarrow> nat"
  where
  "abc_inc_stage4 (s, l, r) ss n ires = 
            (if s \<le> ss+2*n+1 \<and> (s - ss) mod 2 = 0 then 
                if (r\<noteq>[] \<and> hd r = Oc) then 0
                else 1
             else if (s \<le> ss+2*n+1 \<and> (s - ss) mod 2 = Suc 0) 
                                                 then length r
             else if s = ss + 2*n + 6 then 
                  if l = Bk # ires \<and> hd r = Bk then 0
                  else Suc (length l)
             else 0)"
 
fun abc_inc_measure :: "(t_conf \<times> nat \<times> nat \<times> block list) \<Rightarrow> 
                        (nat \<times> nat \<times> nat \<times> nat)"
  where
  "abc_inc_measure (c, ss, n, ires) = 
     (abc_inc_stage1 c ss n, abc_inc_stage2 c ss n, 
      abc_inc_stage3 c ss n ires, abc_inc_stage4 c ss n ires)"

definition abc_inc_LE :: "(((nat \<times> block list \<times> block list) \<times> nat \<times> 
       nat \<times> block list) \<times> ((nat \<times> block list \<times> block list) \<times> nat \<times> nat \<times> block list)) set"
  where "abc_inc_LE \<equiv> (inv_image lex_square abc_inc_measure)"

lemma wf_lex_triple: "wf lex_triple"
by (auto intro:wf_lex_prod simp:lex_triple_def lex_pair_def)

lemma wf_lex_square: "wf lex_square"
by (auto intro:wf_lex_triple simp:lex_triple_def lex_square_def lex_pair_def)

lemma wf_abc_inc_le[intro]: "wf abc_inc_LE"
by(auto intro:wf_inv_image wf_lex_square simp:abc_inc_LE_def)

(********************************************************************)
declare inc_inv.simps[simp del]

lemma halt_lemma2': 
  "\<lbrakk>wf LE;  \<forall> n. ((\<not> P (f n) \<and> Q (f n)) \<longrightarrow> 
    (Q (f (Suc n)) \<and> (f (Suc n), (f n)) \<in> LE)); Q (f 0)\<rbrakk> 
      \<Longrightarrow> \<exists> n. P (f n)"
apply(intro exCI, simp)
apply(subgoal_tac "\<forall> n. Q (f n)", simp)
apply(drule_tac f = f in wf_inv_image)
apply(simp add: inv_image_def)
apply(erule wf_induct, simp)
apply(erule_tac x = x in allE)
apply(erule_tac x = n in allE, erule_tac x = n in allE)
apply(erule_tac x = "Suc x" in allE, simp)
apply(rule_tac allI)
apply(induct_tac n, simp)
apply(erule_tac x = na in allE, simp)
done

lemma halt_lemma2'': 
  "\<lbrakk>P (f n); \<not> P (f (0::nat))\<rbrakk> \<Longrightarrow> 
         \<exists> n. (P (f n) \<and> (\<forall> i < n. \<not> P (f i)))"
apply(induct n rule: nat_less_induct, auto)
done

lemma halt_lemma2''':
 "\<lbrakk>\<forall>n. \<not> P (f n) \<and> Q (f n) \<longrightarrow> Q (f (Suc n)) \<and> (f (Suc n), f n) \<in> LE;
                 Q (f 0);  \<forall>i<na. \<not> P (f i)\<rbrakk> \<Longrightarrow> Q (f na)"
apply(induct na, simp, simp)
done

lemma halt_lemma2: 
  "\<lbrakk>wf LE;  
    \<forall> n. ((\<not> P (f n) \<and> Q (f n)) \<longrightarrow> (Q (f (Suc n)) \<and> (f (Suc n), (f n)) \<in> LE)); 
    Q (f 0); \<not> P (f 0)\<rbrakk> 
  \<Longrightarrow> \<exists> n. P (f n) \<and> Q (f n)"
apply(insert halt_lemma2' [of LE P f Q], simp, erule_tac exE)
apply(subgoal_tac "\<exists> n. (P (f n) \<and> (\<forall> i < n. \<not> P (f i)))")
apply(erule_tac exE)+
apply(rule_tac x = na in exI, auto)
apply(rule halt_lemma2''', simp, simp, simp)
apply(erule_tac halt_lemma2'', simp)
done

lemma [simp]: 
  "\<lbrakk>ly = layout_of aprog; abc_fetch as aprog = Some (Inc n)\<rbrakk>
    \<Longrightarrow> start_of ly (Suc as) = start_of ly as + 2*n +9"
apply(case_tac as, auto simp: abc_fetch.simps start_of.simps 
          layout_of.simps length_of.simps split: if_splits)
done

lemma inc_inv_init: 
 "\<lbrakk>abc_fetch as aprog = Some (Inc n); 
   crsp_l ly (as, am) (start_of ly as, l, r) ires; ly = layout_of aprog\<rbrakk>
  \<Longrightarrow> inc_inv ly n (as, am) (start_of ly as, l, r) ires"
apply(auto simp: crsp_l.simps inc_inv.simps 
      inv_locate_a.simps at_begin_fst_bwtn.simps 
      at_begin_fst_awtn.simps at_begin_norm.simps )
apply(auto intro: startof_not0)
done
     
lemma inc_inv_stop_pre[simp]: 
   "\<lbrakk>ly = layout_of aprog; inc_inv ly n (as, am) (s, l, r) ires; 
     s = start_of ly as; abc_fetch as aprog = Some (Inc n)\<rbrakk>
    \<Longrightarrow>  (\<forall>na. \<not> (\<lambda>((s, l, r), ss, n', ires'). s = start_of ly (Suc as)) 
         (t_steps (s, l, r) (ci ly (start_of ly as) 
          (Inc n), start_of ly as - Suc 0) na, s, n, ires) \<and>
       (\<lambda>((s, l, r), ss, n', ires'). inc_inv ly n (as, am) (s, l, r) ires')
         (t_steps (s, l, r) (ci ly (start_of ly as) 
             (Inc n), start_of ly as - Suc 0) na, s, n, ires) \<longrightarrow>
       (\<lambda>((s, l, r), ss, n', ires'). inc_inv ly n (as, am) (s, l, r) ires') 
      (t_steps (s, l, r) (ci ly (start_of ly as) 
              (Inc n), start_of ly as - Suc 0) (Suc na), s, n, ires) \<and>
     ((t_steps (s, l, r) (ci ly (start_of ly as) (Inc n), 
        start_of ly as - Suc 0) (Suc na), s, n, ires), 
      t_steps (s, l, r) (ci ly (start_of ly as) 
        (Inc n), start_of ly as - Suc 0) na, s, n, ires) \<in> abc_inc_LE)"
apply(rule allI, rule impI, simp add: t_steps_ind,
       rule conjI, erule_tac conjE)
apply(rule_tac inc_inv_step, simp, simp, simp)
apply(case_tac "t_steps (start_of (layout_of aprog) as, l, r) (ci (layout_of aprog) 
  (start_of (layout_of aprog) as) (Inc n), start_of (layout_of aprog) as - Suc 0) na", simp)
proof -
  fix na
  assume h1: "abc_fetch as aprog = Some (Inc n)"
    "\<not> (\<lambda>(s, l, r) (ss, n', ires'). s = start_of (layout_of aprog) as + 2 * n + 9)
    (t_steps (start_of (layout_of aprog) as, l, r) (ci (layout_of aprog) 
    (start_of (layout_of aprog) as) (Inc n), start_of (layout_of aprog) as - Suc 0) na) 
    (start_of (layout_of aprog) as, n, ires) \<and>
    inc_inv (layout_of aprog) n (as, am) (t_steps (start_of (layout_of aprog) as, l, r)
    (ci (layout_of aprog) (start_of (layout_of aprog) as) (Inc n), start_of (layout_of aprog) as - Suc 0) na) ires"
  from h1 have h2: "start_of (layout_of aprog) as > 0"
    apply(rule_tac startof_not0)
    done
  from h1 and h2 show "((t_step (t_steps (start_of (layout_of aprog) as, l, r) (ci (layout_of aprog)
    (start_of (layout_of aprog) as) (Inc n), start_of (layout_of aprog) as - Suc 0) na)
    (ci (layout_of aprog) (start_of (layout_of aprog) as) (Inc n), start_of (layout_of aprog) as - Suc 0),
    start_of (layout_of aprog) as, n, ires),
    t_steps (start_of (layout_of aprog) as, l, r) 
    (ci (layout_of aprog) (start_of (layout_of aprog) as) (Inc n), start_of (layout_of aprog) as - Suc 0) na, 
    start_of (layout_of aprog) as, n, ires)
            \<in> abc_inc_LE"
    apply(case_tac "(t_steps (start_of (layout_of aprog) as, l, r) 
               (ci (layout_of aprog)
         (start_of (layout_of aprog) as) (Inc n), 
           start_of (layout_of aprog) as - Suc 0) na)", simp)
    apply(case_tac "a = 0", 
     auto split:if_splits simp add:t_step.simps inc_inv.simps, 
       tactic {* ALLGOALS (resolve_tac [@{thm fetch_intro}]) *})
    apply(simp_all add:fetch_simps new_tape.simps)
    apply(auto simp add: abc_inc_LE_def  
    lex_square_def lex_triple_def lex_pair_def
      inv_after_write.simps inv_after_move.simps inv_after_clear.simps
      inv_on_left_moving.simps inv_on_left_moving_norm.simps split: if_splits)
    done
qed

lemma inc_inv_stop_pre1: 
  "\<lbrakk>
  ly = layout_of aprog; 
  abc_fetch as aprog = Some (Inc n);
  s = start_of ly as; 
  inc_inv ly n (as, am) (s, l, r) ires
  \<rbrakk> \<Longrightarrow> 
  (\<exists> stp > 0. (\<lambda> (s', l', r').
           s' = start_of ly (Suc as) \<and> 
           inc_inv ly n (as, am) (s', l', r') ires) 
               (t_steps (s, l, r) (ci ly (start_of ly as) (Inc n), 
                        start_of ly as - Suc 0) stp))"
apply(insert halt_lemma2[of abc_inc_LE 
    "\<lambda> ((s, l, r), ss, n', ires'). s = start_of ly (Suc as)" 
    "(\<lambda> stp. (t_steps (s, l, r) 
     (ci ly (start_of ly as) (Inc n), 
     start_of ly as - Suc 0) stp, s, n, ires))" 
    "\<lambda> ((s, l, r), ss, n'). inc_inv ly n (as, am) (s, l, r) ires"])
apply(insert  wf_abc_inc_le)
apply(insert inc_inv_stop_pre[of ly aprog n as am s l r ires], simp)
apply(simp only: t_steps.simps, auto)
apply(rule_tac x = na in exI)
apply(case_tac "(t_steps (start_of (layout_of aprog) as, l, r) 
   (ci (layout_of aprog) (start_of (layout_of aprog) as) 
   (Inc n), start_of (layout_of aprog) as - Suc 0) na)", simp)
apply(case_tac na, simp add: t_steps.simps, simp)
done

lemma inc_inv_stop: 
  assumes program_and_layout: 
  -- {* There is an Abacus program @{text "aprog"} and its layout is @{text "ly"}: *}
  "ly = layout_of aprog"
  and an_instruction:
  -- {* There is an instruction @{text "Inc n"} at postion @{text "as"} of @{text "aprog"} *}
  "abc_fetch as aprog = Some (Inc n)"
  and the_start_state:
  -- {* According to @{text "ly"} and @{text "as"}, 
        the start state of the TM compiled from this
        @{text "Inc n"} instruction should be @{text "s"}:
     *}
  "s = start_of ly as"
  and inv:
  -- {* Invariant holds on configuration @{text "(s, l, r)"} *}
  "inc_inv ly n (as, am) (s, l, r) ires"
  shows  -- {* After @{text "stp"} steps of execution, the compiled 
            TM reaches the start state of next compiled TM and the invariant 
            still holds.
            *}
      "(\<exists> stp > 0. (\<lambda> (s', l', r').
           s' = start_of ly (Suc as) \<and> 
           inc_inv ly n (as, am) (s', l', r') ires) 
               (t_steps (s, l, r) (ci ly (start_of ly as) (Inc n), 
                        start_of ly as - Suc 0) stp))"
proof -
  from inc_inv_stop_pre1 [OF  program_and_layout an_instruction the_start_state inv] 
  show ?thesis .
qed

lemma inc_inv_stop_cond: 
  "\<lbrakk>ly = layout_of aprog; 
    s' = start_of ly (as + 1); 
    inc_inv ly n (as, lm) (s', (l', r')) ires; 
    abc_fetch as aprog = Some (Inc n)\<rbrakk> \<Longrightarrow>
    crsp_l ly (Suc as, abc_lm_s lm n (Suc (abc_lm_v lm n))) 
                                                (s', l', r') ires"
apply(subgoal_tac "s' = start_of ly as + 2*n + 9", simp)
apply(auto simp: inc_inv.simps inv_stop.simps crsp_l.simps )
done

lemma inc_crsp_ex_pre:
  "\<lbrakk>ly = layout_of aprog; 
    crsp_l ly (as, am) tc ires;  
    abc_fetch as aprog = Some (Inc n)\<rbrakk>
 \<Longrightarrow> \<exists>stp > 0. crsp_l ly (abc_step_l (as, am) (Some (Inc n))) 
                (t_steps tc (ci ly (start_of ly as) (Inc n), 
                                start_of ly as - Suc 0) stp) ires"
proof(case_tac tc, simp add: abc_step_l.simps)
  fix a b c
  assume h1: "ly = layout_of aprog" 
         "crsp_l (layout_of aprog) (as, am) (a, b, c) ires"
         "abc_fetch as aprog = Some (Inc n)"
  hence h2: "a = start_of ly as"
    by(auto simp: crsp_l.simps)
  from h1 and h2 have h3: 
       "inc_inv ly n (as, am) (start_of ly as, b, c) ires"
    by(rule_tac inc_inv_init, simp, simp, simp)
  from h1 and h2 and h3 have h4:
       "(\<exists> stp > 0. (\<lambda> (s', l', r'). s' = 
           start_of ly (Suc as) \<and> inc_inv ly n (as, am) (s', l', r') ires)
         (t_steps (a, b, c) (ci ly (start_of ly as) 
                 (Inc n), start_of ly as - Suc 0) stp))"
    apply(rule_tac inc_inv_stop, auto)
    done
  from h1 and h2 and h3 and h4 show 
     "\<exists>stp > 0. crsp_l (layout_of aprog) 
        (Suc as, abc_lm_s am n (Suc (abc_lm_v am n)))
       (t_steps (a, b, c) (ci (layout_of aprog) 
          (start_of (layout_of aprog) as) (Inc n), 
              start_of (layout_of aprog) as - Suc 0) stp) ires"
    apply(erule_tac exE)
    apply(rule_tac x = stp in exI)
    apply(case_tac "(t_steps (a, b, c) (ci (layout_of aprog) 
         (start_of (layout_of aprog) as) (Inc n), 
             start_of (layout_of aprog) as - Suc 0) stp)", simp)
    apply(rule_tac inc_inv_stop_cond, auto)
    done
qed

text {*
  The total correctness of the compilaton of @{text "Inc n"} instruction.
*}

lemma inc_crsp_ex:
  assumes layout: 
  -- {* For any Abacus program @{text "aprog"}, assuming its layout is @{text "ly"} *}
  "ly = layout_of aprog"
  and corresponds: 
  -- {* Abacus configuration @{text "(as, am)"} is in correspondence with 
        TM configuration @{text "tc"} *}
  "crsp_l ly (as, am) tc ires"
  and inc:
  -- {* There is an instruction @{text "Inc n"} at postion @{text "as"} of @{text "aprog"} *}
  "abc_fetch as aprog = Some (Inc n)"
  shows
  -- {* 
  After @{text "stp"} steps of execution, the TM compiled from this @{text "Inc n"}
  stops with a configuration which corresponds to the Abacus configuration obtained
  from the execution of this @{text "Inc n"} instruction.
  *} 
  "\<exists>stp > 0. crsp_l ly (abc_step_l (as, am) (Some (Inc n))) 
                       (t_steps tc (ci ly (start_of ly as) (Inc n), 
                                start_of ly as - Suc 0) stp) ires"
proof -
  from inc_crsp_ex_pre [OF layout corresponds inc] show ?thesis .
qed

(*
subsection {* The compilation of @{text "Dec n e"} *}
*)

text {*
  The lemmas in this section lead to the correctness of the compilation 
  of @{text "Dec n e"} instruction using the same techniques as 
  @{text "Inc n"}.
*}

type_synonym dec_inv_t = "(nat * nat list) \<Rightarrow> t_conf \<Rightarrow> block list \<Rightarrow>  bool"

fun dec_first_on_right_moving :: "nat \<Rightarrow> dec_inv_t"
  where
  "dec_first_on_right_moving n (as, lm) (s, l, r) ires = 
               (\<exists> lm1 lm2 m ml mr rn. lm = lm1 @ [m] @ lm2 \<and> 
         ml + mr = Suc m \<and> length lm1 = n \<and> ml > 0 \<and> m > 0 \<and>
             (if lm1 = [] then l = Oc\<^bsup>ml\<^esup> @ Bk # Bk # ires
                          else  l = (Oc\<^bsup>ml\<^esup>) @ [Bk] @ <rev lm1> @ Bk # Bk # ires) \<and> 
    ((r = (Oc\<^bsup>mr\<^esup>) @ [Bk] @ <lm2> @ (Bk\<^bsup>rn\<^esup>)) \<or> (r = (Oc\<^bsup>mr\<^esup>) \<and> lm2 = [])))"

fun dec_on_right_moving :: "dec_inv_t"
  where
  "dec_on_right_moving (as, lm) (s, l, r) ires =  
   (\<exists> lm1 lm2 m ml mr rn. lm = lm1 @ [m] @ lm2 \<and> 
                             ml + mr = Suc (Suc m) \<and>
   (if lm1 = [] then l = Oc\<^bsup>ml\<^esup> @ Bk # Bk # ires
                else  l = (Oc\<^bsup>ml\<^esup>) @ [Bk] @ <rev lm1> @ Bk # Bk # ires) \<and> 
   ((r = (Oc\<^bsup>mr\<^esup>) @ [Bk] @ <lm2> @ (Bk\<^bsup>rn\<^esup>)) \<or> (r = (Oc\<^bsup>mr\<^esup>) \<and> lm2 = [])))"

fun dec_after_clear :: "dec_inv_t"
  where
  "dec_after_clear (as, lm) (s, l, r) ires = 
              (\<exists> lm1 lm2 m ml mr rn. lm = lm1 @ [m] @ lm2 \<and> 
                ml + mr = Suc m \<and> ml = Suc m \<and> r \<noteq> [] \<and> r \<noteq> [] \<and>
               (if lm1 = [] then l = Oc\<^bsup>ml\<^esup> @ Bk # Bk # ires
                            else l = (Oc\<^bsup>ml \<^esup>) @ [Bk] @ <rev lm1> @ Bk # Bk # ires) \<and> 
               (tl r = Bk # <lm2> @ (Bk\<^bsup>rn\<^esup>) \<or> tl r = [] \<and> lm2 = []))"

fun dec_after_write :: "dec_inv_t"
  where
  "dec_after_write (as, lm) (s, l, r) ires = 
         (\<exists> lm1 lm2 m ml mr rn. lm = lm1 @ [m] @ lm2 \<and> 
       ml + mr = Suc m \<and> ml = Suc m \<and> lm2 \<noteq> [] \<and>
       (if lm1 = [] then l = Bk # Oc\<^bsup>ml\<^esup> @ Bk # Bk # ires
                    else l = Bk # (Oc\<^bsup>ml \<^esup>) @ [Bk] @ <rev lm1> @ Bk # Bk # ires) \<and> 
       tl r = <lm2> @ (Bk\<^bsup>rn\<^esup>))"

fun dec_right_move :: "dec_inv_t"
  where
  "dec_right_move (as, lm) (s, l, r) ires = 
        (\<exists> lm1 lm2 m ml mr rn. lm = lm1 @ [m] @ lm2 
            \<and> ml = Suc m \<and> mr = (0::nat) \<and> 
              (if lm1 = [] then l = Bk # Oc\<^bsup>ml\<^esup> @ Bk # Bk # ires
                          else l = Bk # Oc\<^bsup>ml\<^esup>@ [Bk] @ <rev lm1> @ Bk # Bk # ires) 
           \<and> (r = Bk # <lm2> @ Bk\<^bsup>rn\<^esup>\<or> r = [] \<and> lm2 = []))"

fun dec_check_right_move :: "dec_inv_t"
  where
  "dec_check_right_move (as, lm) (s, l, r) ires = 
        (\<exists> lm1 lm2 m ml mr rn. lm = lm1 @ [m] @ lm2 \<and> 
           ml = Suc m \<and> mr = (0::nat) \<and> 
           (if lm1 = [] then l = Bk # Bk # Oc\<^bsup>ml\<^esup> @ Bk # Bk # ires
                       else l = Bk # Bk # Oc\<^bsup>ml \<^esup>@ [Bk] @ <rev lm1> @ Bk # Bk # ires) \<and> 
           r = <lm2> @ Bk\<^bsup>rn\<^esup>)"

fun dec_left_move :: "dec_inv_t"
  where
  "dec_left_move (as, lm) (s, l, r) ires = 
    (\<exists> lm1 m rn. (lm::nat list) = lm1 @ [m::nat] \<and>   
    rn > 0 \<and> 
   (if lm1 = [] then l = Bk # Oc\<^bsup>Suc m\<^esup> @ Bk # Bk # ires
    else l = Bk # Oc\<^bsup>Suc m\<^esup> @ Bk # <rev lm1> @ Bk # Bk # ires) \<and> r = Bk\<^bsup>rn\<^esup>)"

declare
  dec_on_right_moving.simps[simp del] dec_after_clear.simps[simp del] 
  dec_after_write.simps[simp del] dec_left_move.simps[simp del] 
  dec_check_right_move.simps[simp del] dec_right_move.simps[simp del] 
  dec_first_on_right_moving.simps[simp del]

fun inv_locate_n_b :: "inc_inv_t"
  where
  "inv_locate_n_b (as, lm) (s, l, r) ires= 
    (\<exists> lm1 lm2 tn m ml mr rn. lm @ 0\<^bsup>tn\<^esup> = lm1 @ [m] @ lm2 \<and> 
     length lm1 = s \<and> m + 1 = ml + mr \<and> 
     ml = 1 \<and> tn = s + 1 - length lm \<and>
     (if lm1 = [] then l = Oc\<^bsup>ml\<^esup> @ Bk # Bk # ires
      else l = Oc\<^bsup>ml\<^esup>@Bk#<rev lm1>@Bk#Bk#ires) \<and> 
     (r = (Oc\<^bsup>mr\<^esup>) @ [Bk] @ <lm2>@ (Bk\<^bsup>rn\<^esup>) \<or> (lm2 = [] \<and> r = (Oc\<^bsup>mr\<^esup>)))
  )"

fun dec_inv_1 :: "layout \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> dec_inv_t"
  where
  "dec_inv_1 ly n e (as, am) (s, l, r) ires = 
           (let ss = start_of ly as in
            let am' = abc_lm_s am n (abc_lm_v am n - Suc 0) in
            let am'' = abc_lm_s am n (abc_lm_v am n) in
              if s = start_of ly e then  inv_stop (as, am'') (s, l, r) ires
              else if s = ss then False
              else if ss \<le> s \<and> s < ss + 2*n then
                   if (s - ss) mod 2 = 0 then 
                        inv_locate_a (as, am) ((s - ss) div 2, l, r) ires
                    \<or> inv_locate_a (as, am'') ((s - ss) div 2, l, r) ires
                   else 
                     inv_locate_b (as, am) ((s - ss) div 2, l, r) ires
                  \<or> inv_locate_b (as, am'') ((s - ss) div 2, l, r) ires
              else if s = ss + 2 * n then 
                  inv_locate_a (as, am) (n, l, r) ires
                \<or> inv_locate_a (as, am'') (n, l, r) ires
              else if s = ss + 2 * n + 1 then 
                  inv_locate_b (as, am) (n, l, r) ires
              else if s = ss + 2 * n + 13 then 
                  inv_on_left_moving (as, am'') (s, l, r) ires
              else if s = ss + 2 * n + 14 then 
                  inv_check_left_moving (as, am'') (s, l, r) ires
              else if s = ss + 2 * n + 15 then 
                  inv_after_left_moving (as, am'') (s, l, r) ires
              else False)"

fun dec_inv_2 :: "layout \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> dec_inv_t"
  where
  "dec_inv_2 ly n e (as, am) (s, l, r) ires =
           (let ss = start_of ly as in
            let am' = abc_lm_s am n (abc_lm_v am n - Suc 0) in
            let am'' = abc_lm_s am n (abc_lm_v am n) in
              if s = 0 then False
              else if s = ss then False
              else if ss \<le> s \<and> s < ss + 2*n then
                   if (s - ss) mod 2 = 0 then 
                      inv_locate_a (as, am) ((s - ss) div 2, l, r) ires
                   else inv_locate_b (as, am) ((s - ss) div 2, l, r) ires
              else if s = ss + 2 * n then 
                      inv_locate_a (as, am) (n, l, r) ires
              else if s = ss + 2 * n + 1 then 
                      inv_locate_n_b (as, am) (n, l, r) ires
              else if s = ss + 2 * n + 2 then 
                      dec_first_on_right_moving n (as, am'') (s, l, r) ires
              else if s = ss + 2 * n + 3 then 
                      dec_after_clear (as, am') (s, l, r) ires
              else if s = ss + 2 * n + 4 then 
                      dec_right_move (as, am') (s, l, r) ires
              else if s = ss + 2 * n + 5 then 
                      dec_check_right_move (as, am') (s, l, r) ires
              else if s = ss + 2 * n + 6 then 
                      dec_left_move (as, am') (s, l, r) ires
              else if s = ss + 2 * n + 7 then 
                      dec_after_write (as, am') (s, l, r) ires
              else if s = ss + 2 * n + 8 then 
                      dec_on_right_moving (as, am') (s, l, r) ires
              else if s = ss + 2 * n + 9 then 
                      dec_after_clear (as, am') (s, l, r) ires
              else if s = ss + 2 * n + 10 then 
                      inv_on_left_moving (as, am') (s, l, r) ires
              else if s = ss + 2 * n + 11 then 
                      inv_check_left_moving (as, am') (s, l, r) ires
              else if s = ss + 2 * n + 12 then 
                      inv_after_left_moving (as, am') (s, l, r) ires
              else if s = ss + 2 * n + 16 then 
                      inv_stop (as, am') (s, l, r) ires
              else False)"

(*begin: dec_fetch lemmas*)

lemma dec_fetch_locate_a_o: 
      "\<lbrakk>start_of ly as \<le> a;
        a < start_of ly as + 2 * n; start_of ly as > 0;
        a - start_of ly as = 2 * q\<rbrakk>
       \<Longrightarrow> fetch (ci (layout_of aprog) 
         (start_of ly as) (Dec n e)) (Suc (2 * q))  Oc = (R, a + 1)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append Suc_pre)
apply(subgoal_tac "(findnth n ! Suc (4 * q)) = 
                          findnth (Suc q) ! (4 * q + 1)")
apply(simp add: findnth.simps nth_append)
apply(subgoal_tac " findnth n !(4 * q + 1) = 
                          findnth (Suc q) ! (4 * q + 1)", simp)
apply(rule_tac findnth_nth, auto)
done

lemma  dec_fetch_locate_a_b:
       "\<lbrakk>start_of ly as \<le> a; 
         a < start_of ly as + 2 * n; 
         start_of ly as > 0;
         a - start_of ly as = 2 * q\<rbrakk>
       \<Longrightarrow> fetch (ci (layout_of aprog) (start_of ly as) (Dec n e)) 
              (Suc (2 * q))  Bk = (W1, a)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append)
apply(subgoal_tac "(findnth n ! (4 * q)) = 
                       findnth (Suc q) ! (4 * q )")
apply(simp add: findnth.simps nth_append)
apply(subgoal_tac " findnth n !(4 * q + 0) = 
                       findnth (Suc q) ! (4 * q + 0)", simp)
apply(rule_tac findnth_nth, auto)
done

lemma dec_fetch_locate_b_o:
      "\<lbrakk>start_of ly as \<le> a; 
        a < start_of ly as + 2 * n; 
        (a - start_of ly as) mod 2 = Suc 0; 
        start_of ly as> 0\<rbrakk>
       \<Longrightarrow> fetch (ci (layout_of aprog) (start_of ly as) (Dec n e)) 
                       (Suc (a - start_of ly as)) Oc = (R, a)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append)
apply(subgoal_tac "\<exists> q. (a - start_of ly as) = 2 * q + 1", auto)
apply(subgoal_tac "(findnth n ! Suc (Suc (Suc (4 * q)))) = 
                                findnth (Suc q) ! (4 * q + 3)")
apply(simp add: findnth.simps nth_append)
apply(subgoal_tac " findnth n ! (4 * q + 3) = 
                 findnth (Suc q) ! (4 * q + 3)", simp add: add3_Suc)
apply(rule_tac findnth_nth, auto)
done

lemma dec_fetch_locate_b_b: 
      "\<lbrakk>\<not> a < start_of ly as; 
        a < start_of ly as + 2 * n; 
       (a - start_of ly as) mod 2 = Suc 0; 
        start_of ly as > 0\<rbrakk>
       \<Longrightarrow> fetch (ci (layout_of aprog) (start_of ly as) (Dec n e)) 
              (Suc (a - start_of ly as))  Bk = (R, a + 1)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append)
apply(subgoal_tac "\<exists> q. (a - start_of ly as) = 2 * q + 1", auto)
apply(subgoal_tac "(findnth n ! Suc ((Suc (4 * q)))) = 
                          findnth (Suc q) ! (4 * q + 2)")
apply(simp add: findnth.simps nth_append)
apply(subgoal_tac " findnth n ! (4 * q + 2) = 
                          findnth (Suc q) ! (4 * q + 2)", simp)
apply(rule_tac findnth_nth, auto)
done

lemma dec_fetch_locate_n_a_o: 
       "start_of ly as > 0 \<Longrightarrow> fetch (ci (layout_of aprog) 
                       (start_of ly as) (Dec n e)) (Suc (2 * n))  Oc
       = (R, start_of ly as + 2*n + 1)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tdec_b_def)
done

lemma dec_fetch_locate_n_a_b: 
       "start_of ly as > 0 \<Longrightarrow> fetch (ci (layout_of aprog) 
                       (start_of ly as) (Dec n e)) (Suc (2 * n))  Bk
       = (W1, start_of ly as + 2*n)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tdec_b_def)
done

lemma dec_fetch_locate_n_b_o: 
       "start_of ly as > 0 \<Longrightarrow> 
            fetch (ci (layout_of aprog) 
                (start_of ly as) (Dec n e)) (Suc (Suc (2 * n)))  Oc
      = (R, start_of ly as + 2*n + 2)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tdec_b_def)
done


lemma dec_fetch_locate_n_b_b: 
       "start_of ly as > 0 \<Longrightarrow> 
       fetch (ci (layout_of aprog) 
                  (start_of ly as) (Dec n e)) (Suc (Suc (2 * n))) Bk
      = (L, start_of ly as + 2*n + 13)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tdec_b_def)
done

lemma dec_fetch_first_on_right_move_o: 
      "start_of ly as > 0 \<Longrightarrow> 
       fetch (ci (layout_of aprog) 
             (start_of ly as) (Dec n e)) (Suc (Suc (Suc (2 * n))))  Oc
     = (R, start_of ly as + 2*n + 2)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tdec_b_def)
done

lemma dec_fetch_first_on_right_move_b: 
      "start_of ly as > 0 \<Longrightarrow> 
      fetch (ci (layout_of aprog) (start_of ly as) (Dec n e)) 
                             (Suc (Suc (Suc (2 * n))))  Bk
     = (L, start_of ly as + 2*n + 3)"
apply(auto simp: ci.simps findnth.simps fetch.simps
                  nth_of.simps tshift.simps nth_append tdec_b_def)
done

lemma [simp]: "fetch x (a + 2 * n) b = fetch x (2 * n + a) b"
thm arg_cong
apply(rule_tac x = "a + 2*n" and y = "2*n + a" in arg_cong, simp)
done

lemma dec_fetch_first_after_clear_o: 
     "start_of ly as > 0 \<Longrightarrow> fetch (ci (layout_of aprog) 
                      (start_of ly as) (Dec n e)) (2 * n + 4) Oc
    = (W0, start_of ly as + 2*n + 3)"
apply(auto simp: ci.simps findnth.simps tshift.simps 
                          tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 4 = Suc (2*n + 3)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_first_after_clear_b: 
     "start_of ly as > 0 \<Longrightarrow> 
     fetch (ci (layout_of aprog) 
                   (start_of ly as) (Dec n e)) (2 * n + 4) Bk
    = (R, start_of ly as + 2*n + 4)"
apply(auto simp: ci.simps findnth.simps 
               tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 4= Suc (2*n + 3)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_right_move_b: 
     "start_of ly as > 0 \<Longrightarrow> fetch (ci (layout_of aprog) 
                          (start_of ly as) (Dec n e)) (2 * n + 5) Bk
    = (R, start_of ly as + 2*n + 5)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 5= Suc (2*n + 4)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_check_right_move_b: 
     "start_of ly as > 0 \<Longrightarrow> 
      fetch (ci (layout_of aprog)
                (start_of ly as) (Dec n e)) (2 * n + 6) Bk
    = (L, start_of ly as + 2*n + 6)"
apply(auto simp: ci.simps findnth.simps 
               tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 6 = Suc (2*n + 5)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_check_right_move_o: 
     "start_of ly as > 0 \<Longrightarrow> 
    fetch (ci (layout_of aprog) (start_of ly as) 
                      (Dec n e)) (2 * n + 6) Oc
    = (L, start_of ly as + 2*n + 7)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 6 = Suc (2*n + 5)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_left_move_b: 
     "start_of ly as > 0 \<Longrightarrow> 
     fetch (ci (layout_of aprog) 
             (start_of ly as) (Dec n e)) (2 * n + 7) Bk
    = (L, start_of ly as + 2*n + 10)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 7 = Suc (2*n + 6)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_after_write_b: 
     "start_of ly as > 0 \<Longrightarrow> 
    fetch (ci (layout_of aprog) 
                   (start_of ly as) (Dec n e)) (2 * n + 8) Bk
    = (W1, start_of ly as + 2*n + 7)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 8 = Suc (2*n + 7)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_after_write_o: 
     "start_of ly as > 0 \<Longrightarrow> 
     fetch (ci (layout_of aprog) 
                   (start_of ly as) (Dec n e)) (2 * n + 8) Oc
    = (R, start_of ly as + 2*n + 8)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 8 = Suc (2*n + 7)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_on_right_move_b: 
     "start_of ly as > 0 \<Longrightarrow> 
     fetch (ci (layout_of aprog) 
                   (start_of ly as) (Dec n e)) (2 * n + 9) Bk
    = (L, start_of ly as + 2*n + 9)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 9 = Suc (2*n + 8)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_on_right_move_o: 
     "start_of ly as > 0 \<Longrightarrow> 
     fetch (ci (layout_of aprog) 
             (start_of ly as) (Dec n e)) (2 * n + 9) Oc
    = (R, start_of ly as + 2*n + 8)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 9 = Suc (2*n + 8)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_after_clear_b: 
     "start_of ly as > 0 \<Longrightarrow> 
     fetch (ci (layout_of aprog) 
            (start_of ly as) (Dec n e)) (2 * n + 10) Bk
    = (R, start_of ly as + 2*n + 4)" 
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 10 = Suc (2*n + 9)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_after_clear_o: 
     "start_of ly as > 0 \<Longrightarrow> 
    fetch (ci (layout_of aprog) 
             (start_of ly as) (Dec n e)) (2 * n + 10) Oc
    = (W0, start_of ly as + 2*n + 9)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 10= Suc (2*n + 9)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_on_left_move1_o:
      "start_of ly as > 0 \<Longrightarrow> 
    fetch (ci (layout_of aprog) 
           (start_of ly as) (Dec n e)) (2 * n + 11) Oc
    = (L, start_of ly as + 2*n + 10)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 11= Suc (2*n + 10)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_on_left_move1_b:
     "start_of ly as > 0 \<Longrightarrow> 
    fetch (ci (layout_of aprog) 
             (start_of ly as) (Dec n e)) (2 * n + 11) Bk
    = (L, start_of ly as + 2*n + 11)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 11 = Suc (2*n + 10)", 
      simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_check_left_move1_o: 
    "start_of ly as > 0 \<Longrightarrow> 
  fetch (ci (layout_of aprog) 
             (start_of ly as) (Dec n e)) (2 * n + 12) Oc
    = (L, start_of ly as + 2*n + 10)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 12= Suc (2*n + 11)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_check_left_move1_b: 
    "start_of ly as > 0 \<Longrightarrow> 
   fetch (ci (layout_of aprog) 
                  (start_of ly as) (Dec n e)) (2 * n + 12) Bk
    = (R, start_of ly as + 2*n + 12)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 12 = Suc (2*n + 11)", 
      simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_after_left_move1_b: 
  "start_of ly as > 0 \<Longrightarrow> 
  fetch (ci (layout_of aprog) 
                (start_of ly as) (Dec n e)) (2 * n + 13) Bk
    = (R, start_of ly as + 2*n + 16)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 13 = Suc (2*n + 12)", 
      simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_on_left_move2_o:
  "start_of ly as > 0 \<Longrightarrow> 
  fetch (ci (layout_of aprog) 
           (start_of ly as) (Dec n e)) (2 * n + 14) Oc
   = (L, start_of ly as + 2*n + 13)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 14 = Suc (2*n + 13)", 
      simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_on_left_move2_b:
  "start_of ly as > 0 \<Longrightarrow> 
  fetch (ci (layout_of aprog) 
              (start_of ly as) (Dec n e)) (2 * n + 14) Bk
 = (L, start_of ly as + 2*n + 14)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 14 = Suc (2*n + 13)", 
      simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_check_left_move2_o:
  "start_of ly as > 0 \<Longrightarrow> 
  fetch (ci (layout_of aprog) 
                (start_of ly as) (Dec n e)) (2 * n + 15)  Oc
 = (L, start_of ly as + 2*n + 13)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 15 = Suc (2*n + 14)", 
      simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_check_left_move2_b:
  "start_of ly as > 0 \<Longrightarrow> 
  fetch (ci (layout_of aprog) 
                (start_of ly as) (Dec n e)) (2 * n + 15)  Bk
 = (R, start_of ly as + 2*n + 15)"
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 15= Suc (2*n + 14)", simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_after_left_move2_b: 
  "\<lbrakk>ly = layout_of aprog; 
    abc_fetch as aprog = Some (Dec n e); 
    start_of ly as > 0\<rbrakk> \<Longrightarrow> 
     fetch (ci (layout_of aprog) (start_of ly as) 
              (Dec n e)) (2 * n + 16)  Bk
 = (R, start_of ly e)" 
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac "2*n + 16 = Suc (2*n + 15)",
      simp only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

lemma dec_fetch_next_state: 
    "start_of ly as > 0 \<Longrightarrow> 
    fetch (ci (layout_of aprog) 
           (start_of ly as) (Dec n e)) (2* n + 17)  b
    = (Nop, 0)"
apply(case_tac b)
apply(auto simp: ci.simps findnth.simps 
                 tshift.simps tdec_b_def add3_Suc)
apply(subgoal_tac [!] "2*n + 17 = Suc (2*n + 16)", 
      simp_all only: fetch.simps)
apply(auto simp: nth_of.simps nth_append)
done

(*End: dec_fetch lemmas*)
lemmas dec_fetch_simps = 
 dec_fetch_locate_a_o dec_fetch_locate_a_b dec_fetch_locate_b_o 
 dec_fetch_locate_b_b dec_fetch_locate_n_a_o 
 dec_fetch_locate_n_a_b dec_fetch_locate_n_b_o 
 dec_fetch_locate_n_b_b dec_fetch_first_on_right_move_o 
 dec_fetch_first_on_right_move_b dec_fetch_first_after_clear_b
 dec_fetch_first_after_clear_o dec_fetch_right_move_b 
 dec_fetch_on_right_move_b dec_fetch_on_right_move_o 
 dec_fetch_after_clear_b dec_fetch_after_clear_o
 dec_fetch_check_right_move_b dec_fetch_check_right_move_o 
 dec_fetch_left_move_b dec_fetch_on_left_move1_b 
 dec_fetch_on_left_move1_o dec_fetch_check_left_move1_b 
 dec_fetch_check_left_move1_o dec_fetch_after_left_move1_b 
 dec_fetch_on_left_move2_b dec_fetch_on_left_move2_o
 dec_fetch_check_left_move2_o dec_fetch_check_left_move2_b 
 dec_fetch_after_left_move2_b dec_fetch_after_write_b 
 dec_fetch_after_write_o dec_fetch_next_state

lemma [simp]:
  "\<lbrakk>start_of ly as \<le> a; 
    a < start_of ly as + 2 * n; 
    (a - start_of ly as) mod 2 = Suc 0; 
    inv_locate_b (as, am) ((a - start_of ly as) div 2, aaa, Bk # xs) ires\<rbrakk>
     \<Longrightarrow> \<not> Suc a < start_of ly as + 2 * n \<longrightarrow> 
                inv_locate_a (as, am) (n, Bk # aaa, xs) ires"
apply(insert locate_b_2_locate_a[of a ly as n am aaa xs], simp)
done
 
lemma [simp]: 
  "\<lbrakk>start_of ly as \<le> a; 
    a < start_of ly as + 2 * n; 
    (a - start_of ly as) mod 2 = Suc 0; 
    inv_locate_b (as, am) ((a - start_of ly as) div 2, aaa, []) ires\<rbrakk>
   \<Longrightarrow> \<not> Suc a < start_of ly as + 2 * n \<longrightarrow> 
                  inv_locate_a (as, am) (n, Bk # aaa, []) ires"
apply(insert locate_b_2_locate_a_B[of a ly as n am aaa], simp)
done

(*
lemma [simp]: "a\<^bsup>0\<^esup>=[]"
apply(simp add: exponent_def)
done
*)

lemma exp_ind: "a\<^bsup>Suc b\<^esup> =  a\<^bsup>b\<^esup> @ [a]"
apply(simp only: exponent_def rep_ind)
done

lemma [simp]:
  "inv_locate_b (as, am) (n, l, Oc # r) ires
  \<Longrightarrow> dec_first_on_right_moving n (as,  abc_lm_s am n (abc_lm_v am n))
                      (Suc (Suc (start_of ly as + 2 * n)), Oc # l, r) ires"
apply(simp only: inv_locate_b.simps 
     dec_first_on_right_moving.simps in_middle.simps 
     abc_lm_s.simps abc_lm_v.simps)
apply(erule_tac exE)+
apply(erule conjE)+
apply(case_tac "n < length am", simp)
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = m in exI, simp)
apply(rule_tac x = "Suc ml" in exI, rule_tac conjI, rule_tac [1-2] impI)
prefer 3
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = m in exI, simp)
apply(subgoal_tac "Suc n - length am = Suc (n - length am)",
      simp only:exponent_def rep_ind, simp)
apply(rule_tac x = "Suc ml" in exI, simp_all)
apply(rule_tac [!] x = "mr - 1" in exI, simp_all)
apply(case_tac [!] mr, auto)
done

lemma [simp]: 
  "\<lbrakk>inv_locate_b (as, am) (n, l, r) ires; l \<noteq> []\<rbrakk> \<Longrightarrow> 
  \<not> inv_on_left_moving_in_middle_B (as, abc_lm_s am n (abc_lm_v am n)) 
    (s, tl l, hd l # r) ires"
apply(auto simp: inv_locate_b.simps 
                 inv_on_left_moving_in_middle_B.simps in_middle.simps)
apply(case_tac [!] ml, auto split: if_splits)
done

lemma [simp]: "inv_locate_b (as, am) (n, l, r) ires \<Longrightarrow> l \<noteq> []"
apply(auto simp: inv_locate_b.simps in_middle.simps split: if_splits)
done

lemma [simp]: "\<lbrakk>inv_locate_b (as, am) (n, l, Bk # r) ires; n < length am\<rbrakk>
     \<Longrightarrow> inv_on_left_moving_norm (as, am) (s, tl l, hd l # Bk # r) ires"
apply(simp only: inv_locate_b.simps inv_on_left_moving_norm.simps 
                 in_middle.simps)
apply(erule_tac exE)+
apply(erule_tac conjE)+
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = m in exI, simp)
apply(rule_tac x = "ml - 1" in exI, auto)
apply(rule_tac [!] x = "Suc mr" in exI)
apply(case_tac [!] mr, auto)
done

lemma [simp]: "\<lbrakk>inv_locate_b (as, am) (n, l, Bk # r) ires; \<not> n < length am\<rbrakk>
    \<Longrightarrow> inv_on_left_moving_norm (as, am @ 
        replicate (n - length am) 0 @ [0]) (s, tl l, hd l # Bk # r) ires"
apply(simp only: inv_locate_b.simps inv_on_left_moving_norm.simps 
                 in_middle.simps)
apply(erule_tac exE)+
apply(erule_tac conjE)+
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = m in exI, simp)
apply(subgoal_tac "Suc n - length am = Suc (n - length am)", simp only: rep_ind exponent_def, simp_all)
apply(rule_tac x = "Suc mr" in exI, auto)
done

lemma inv_locate_b_2_on_left_moving[simp]: 
  "\<lbrakk>inv_locate_b (as, am) (n, l, Bk # r) ires\<rbrakk>
   \<Longrightarrow> (l = [] \<longrightarrow> inv_on_left_moving (as,  
            abc_lm_s am n (abc_lm_v am n)) (s, [], Bk # Bk # r) ires) \<and>
       (l \<noteq> [] \<longrightarrow> inv_on_left_moving (as,  
            abc_lm_s am n (abc_lm_v am n)) (s, tl l, hd l # Bk # r) ires)"
apply(subgoal_tac "l\<noteq>[]")
apply(subgoal_tac "\<not> inv_on_left_moving_in_middle_B 
      (as,  abc_lm_s am n (abc_lm_v am n)) (s, tl l, hd l # Bk # r) ires")
apply(simp add:inv_on_left_moving.simps 
          abc_lm_s.simps abc_lm_v.simps split: if_splits, auto)
done

lemma [simp]: 
  "inv_locate_b (as, am) (n, l, []) ires \<Longrightarrow> 
                   inv_locate_b (as, am) (n, l, [Bk]) ires" 
apply(auto simp: inv_locate_b.simps in_middle.simps)
apply(rule_tac x = lm1 in exI, rule_tac x = "[]" in exI,
      rule_tac x = "Suc (length lm1) - length am" in exI, 
      rule_tac x = m in exI, simp)
apply(rule_tac x = ml in exI, rule_tac x = mr in exI)
apply(auto)
done

lemma nil_2_nil: "<lm::nat list> = [] \<Longrightarrow> lm = []"
apply(auto simp: tape_of_nl_abv)
apply(case_tac lm, simp)
apply(case_tac list, auto simp: tape_of_nat_list.simps)
done

lemma  inv_locate_b_2_on_left_moving_b[simp]: 
   "inv_locate_b (as, am) (n, l, []) ires
     \<Longrightarrow> (l = [] \<longrightarrow> inv_on_left_moving (as, 
                  abc_lm_s am n (abc_lm_v am n)) (s, [], [Bk]) ires) \<and>
         (l \<noteq> [] \<longrightarrow> inv_on_left_moving (as, abc_lm_s am n 
                  (abc_lm_v am n)) (s, tl l, [hd l]) ires)"
apply(insert inv_locate_b_2_on_left_moving[of as am n l "[]" ires s])
apply(simp only: inv_on_left_moving.simps, simp)
apply(subgoal_tac "\<not> inv_on_left_moving_in_middle_B 
         (as, abc_lm_s am n (abc_lm_v am n)) (s, tl l, [hd l]) ires", simp)
apply(simp only: inv_on_left_moving_norm.simps)
apply(erule_tac exE)+
apply(erule_tac conjE)+
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = m in exI, rule_tac x = ml in exI, 
      rule_tac x = mr in exI, simp)
apply(case_tac mr, simp, simp, case_tac nat, auto intro: nil_2_nil)
done

lemma [simp]: 
 "\<lbrakk>dec_first_on_right_moving n (as, am) (s, aaa, Oc # xs) ires\<rbrakk>
   \<Longrightarrow> dec_first_on_right_moving n (as, am) (s', Oc # aaa, xs) ires"
apply(simp only: dec_first_on_right_moving.simps)
apply(erule exE)+
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = m in exI, simp)
apply(rule_tac x = "Suc ml" in exI, 
      rule_tac x = "mr - 1" in exI, auto)
apply(case_tac [!] mr, auto)
done

lemma [simp]: 
  "dec_first_on_right_moving n (as, am) (s, l, Bk # xs) ires \<Longrightarrow> l \<noteq> []"
apply(auto simp: dec_first_on_right_moving.simps split: if_splits)
done

lemma [elim]: 
  "\<lbrakk>\<not> length lm1 < length am; 
    am @ replicate (length lm1 - length am) 0 @ [0::nat] = 
                                                lm1 @ m # lm2;
    0 < m\<rbrakk>
   \<Longrightarrow> RR"
apply(subgoal_tac "lm2 = []", simp)
apply(drule_tac length_equal, simp)
done

lemma [simp]: 
 "\<lbrakk>dec_first_on_right_moving n (as, 
                   abc_lm_s am n (abc_lm_v am n)) (s, l, Bk # xs) ires\<rbrakk>
\<Longrightarrow> dec_after_clear (as, abc_lm_s am n 
                 (abc_lm_v am n - Suc 0)) (s', tl l, hd l # Bk # xs) ires"
apply(simp only: dec_first_on_right_moving.simps 
                 dec_after_clear.simps abc_lm_s.simps abc_lm_v.simps)
apply(erule_tac exE)+
apply(case_tac "n < length am")
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = "m - 1" in exI, auto simp: )
apply(case_tac [!] mr, auto)
done

lemma [simp]: 
 "\<lbrakk>dec_first_on_right_moving n (as, 
                   abc_lm_s am n (abc_lm_v am n)) (s, l, []) ires\<rbrakk>
\<Longrightarrow> (l = [] \<longrightarrow> dec_after_clear (as, 
             abc_lm_s am n (abc_lm_v am n - Suc 0)) (s', [], [Bk]) ires) \<and>
    (l \<noteq> [] \<longrightarrow> dec_after_clear (as, abc_lm_s am n 
                      (abc_lm_v am n - Suc 0)) (s', tl l, [hd l]) ires)"
apply(subgoal_tac "l \<noteq> []", 
      simp only: dec_first_on_right_moving.simps 
                 dec_after_clear.simps abc_lm_s.simps abc_lm_v.simps)
apply(erule_tac exE)+
apply(case_tac "n < length am", simp)
apply(rule_tac x = lm1 in exI, rule_tac x = "m - 1" in exI, auto)
apply(case_tac [1-2] mr, auto)
apply(case_tac [1-2] m, auto simp: dec_first_on_right_moving.simps split: if_splits)
done

lemma [simp]: "\<lbrakk>dec_after_clear (as, am) (s, l, Oc # r) ires\<rbrakk>
                \<Longrightarrow> dec_after_clear (as, am) (s', l, Bk # r) ires"
apply(auto simp: dec_after_clear.simps)
done

lemma [simp]: "\<lbrakk>dec_after_clear (as, am) (s, l, Bk # r) ires\<rbrakk>
                \<Longrightarrow> dec_right_move (as, am) (s', Bk # l, r) ires"
apply(auto simp: dec_after_clear.simps dec_right_move.simps split: if_splits)
done

lemma [simp]: "\<lbrakk>dec_after_clear (as, am) (s, l, []) ires\<rbrakk>
             \<Longrightarrow> dec_right_move (as, am) (s', Bk # l, []) ires"
apply(auto simp: dec_after_clear.simps dec_right_move.simps )
done

lemma [simp]: "\<exists>rn. a::block\<^bsup>rn\<^esup> = []"
apply(rule_tac x = 0 in exI, simp)
done

lemma [simp]: "\<lbrakk>dec_after_clear (as, am) (s, l, []) ires\<rbrakk>
             \<Longrightarrow> dec_right_move (as, am) (s', Bk # l, [Bk]) ires"
apply(auto simp: dec_after_clear.simps dec_right_move.simps split: if_splits)
done

lemma [simp]:"dec_right_move (as, am) (s, l, Oc # r) ires = False"
apply(auto simp: dec_right_move.simps)
done
              
lemma dec_right_move_2_check_right_move[simp]:
     "\<lbrakk>dec_right_move (as, am) (s, l, Bk # r) ires\<rbrakk>
      \<Longrightarrow> dec_check_right_move (as, am) (s', Bk # l, r) ires"
apply(auto simp: dec_right_move.simps dec_check_right_move.simps split: if_splits)
done

lemma [simp]: 
 "dec_right_move (as, am) (s, l, []) ires= 
  dec_right_move (as, am) (s, l, [Bk]) ires"
apply(simp add: dec_right_move.simps)
apply(rule_tac iffI)
apply(erule_tac [!] exE)+
apply(erule_tac [2] exE)
apply(rule_tac [!] x = lm1 in exI, rule_tac x = "[]" in exI, 
      rule_tac [!] x = m in exI, auto)
apply(auto intro: nil_2_nil)
done

lemma [simp]: "\<lbrakk>dec_right_move (as, am) (s, l, []) ires\<rbrakk>
             \<Longrightarrow> dec_check_right_move (as, am) (s, Bk # l, []) ires"
apply(insert dec_right_move_2_check_right_move[of as am s l "[]" s'], 
      simp)
done

lemma [simp]: "dec_check_right_move (as, am) (s, l, r) ires\<Longrightarrow> l \<noteq> []"
apply(auto simp: dec_check_right_move.simps split: if_splits)
done
 
lemma [simp]: "\<lbrakk>dec_check_right_move (as, am) (s, l, Oc # r) ires\<rbrakk>
             \<Longrightarrow> dec_after_write (as, am) (s', tl l, hd l # Oc # r) ires"
apply(auto simp: dec_check_right_move.simps dec_after_write.simps)
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = m in exI, auto)
done

lemma [simp]: "\<lbrakk>dec_check_right_move (as, am) (s, l, Bk # r) ires\<rbrakk>
                \<Longrightarrow> dec_left_move (as, am) (s', tl l, hd l # Bk # r) ires"
apply(auto simp: dec_check_right_move.simps 
                 dec_left_move.simps inv_after_move.simps)
apply(rule_tac x = lm1 in exI, rule_tac x = m in exI, auto)
apply(auto intro: BkCons_nil nil_2_nil dest: BkCons_nil)
apply(rule_tac x = "Suc rn" in exI)
apply(auto intro: BkCons_nil nil_2_nil dest: BkCons_nil)
done

lemma [simp]: "\<lbrakk>dec_check_right_move (as, am) (s, l, []) ires\<rbrakk>
             \<Longrightarrow> dec_left_move (as, am) (s', tl l, [hd l]) ires"
apply(auto simp: dec_check_right_move.simps 
                 dec_left_move.simps inv_after_move.simps)
apply(rule_tac x = lm1 in exI, rule_tac x = m in exI, auto)
apply(auto intro: BkCons_nil nil_2_nil dest: BkCons_nil)
done

lemma [simp]: "dec_left_move (as, am) (s, aaa, Oc # xs) ires = False"
apply(auto simp: dec_left_move.simps inv_after_move.simps)
apply(case_tac [!] rn, auto)
done

lemma [simp]: "dec_left_move (as, am) (s, l, r) ires
             \<Longrightarrow> l \<noteq> []"
apply(auto simp: dec_left_move.simps split: if_splits)
done

lemma tape_of_nl_abv_cons_ex[simp]: 
   "\<exists>lna. Oc # Oc\<^bsup>m\<^esup> @ Bk # <rev lm1> @ Bk\<^bsup>ln\<^esup> = <m # rev lm1> @ Bk\<^bsup>lna\<^esup>"
apply(case_tac "lm1=[]", auto simp: tape_of_nl_abv 
                                    tape_of_nat_list.simps)
apply(rule_tac x = "ln" in exI, simp)
apply(simp add:  tape_of_nat_list_cons exponent_def)
done

(*
lemma [simp]: "inv_on_left_moving_in_middle_B (as, lm1 @ [m])
                 (s', Oc # Oc\<^bsup>m\<^esup> @ Bk # <rev lm1> @ Bk\<^bsup>ln\<^esup>, Bk # Bk\<^bsup>rn\<^esup>) ires"
apply(simp only: inv_on_left_moving_in_middle_B.simps)
apply(rule_tac x = "lm1 @ [m]" in exI, rule_tac x = "[]" in exI, auto)
done    
*)
lemma [simp]: "inv_on_left_moving_in_middle_B (as, [m])
  (s', Oc # Oc\<^bsup>m\<^esup> @ Bk # Bk # ires, Bk # Bk\<^bsup>rn\<^esup>) ires"
apply(simp add: inv_on_left_moving_in_middle_B.simps)
apply(rule_tac x = "[m]" in exI, simp, auto simp: tape_of_nat_def)
done

lemma [simp]: "inv_on_left_moving_in_middle_B (as, [m])
  (s', Oc # Oc\<^bsup>m\<^esup> @ Bk # Bk # ires, [Bk]) ires"
apply(simp add: inv_on_left_moving_in_middle_B.simps)
apply(rule_tac x = "[m]" in exI, simp, auto simp: tape_of_nat_def)
done

lemma [simp]: "lm1 \<noteq> [] \<Longrightarrow> 
  inv_on_left_moving_in_middle_B (as, lm1 @ [m]) (s', 
  Oc # Oc\<^bsup>m\<^esup> @ Bk # <rev lm1> @ Bk # Bk # ires, Bk # Bk\<^bsup>rn\<^esup>) ires"
apply(simp only: inv_on_left_moving_in_middle_B.simps)
apply(rule_tac x = "lm1 @ [m ]" in exI, rule_tac x = "[]" in exI, simp, auto)
done

lemma [simp]: "lm1 \<noteq> [] \<Longrightarrow> 
  inv_on_left_moving_in_middle_B (as, lm1 @ [m]) (s', 
  Oc # Oc\<^bsup>m\<^esup> @ Bk # <rev lm1> @ Bk # Bk # ires, [Bk]) ires"
apply(simp only: inv_on_left_moving_in_middle_B.simps)
apply(rule_tac x = "lm1 @ [m ]" in exI, rule_tac x = "[]" in exI, simp, auto)
done

lemma [simp]: "dec_left_move (as, am) (s, l, Bk # r) ires
       \<Longrightarrow> inv_on_left_moving (as, am) (s', tl l, hd l # Bk # r) ires"
apply(auto simp: dec_left_move.simps inv_on_left_moving.simps split: if_splits)
done

(*
lemma [simp]: "inv_on_left_moving_in_middle_B (as, lm1 @ [m]) 
                        (s', Oc # Oc\<^bsup>m\<^esup> @ Bk # <rev lm1> @ Bk\<^bsup>ln\<^esup>, [Bk])  ires"
apply(auto simp: inv_on_left_moving_in_middle_B.simps)
apply(rule_tac x = "lm1 @ [m]" in exI, rule_tac x = "[]" in exI, auto)
done
*)

lemma [simp]: "dec_left_move (as, am) (s, l, []) ires
             \<Longrightarrow> inv_on_left_moving (as, am) (s', tl l, [hd l]) ires"
apply(auto simp: dec_left_move.simps inv_on_left_moving.simps split: if_splits)
done

lemma [simp]: "dec_after_write (as, am) (s, l, Oc # r) ires
       \<Longrightarrow> dec_on_right_moving (as, am) (s', Oc # l, r) ires"
apply(auto simp: dec_after_write.simps dec_on_right_moving.simps)
apply(rule_tac x = "lm1 @ [m]" in exI, rule_tac x = "tl lm2" in exI, 
      rule_tac x = "hd lm2" in exI, simp)
apply(rule_tac x = "Suc 0" in exI,rule_tac x =  "Suc (hd lm2)" in exI)
apply(case_tac lm2, simp, simp)
apply(case_tac "list = []", 
      auto simp: tape_of_nl_abv tape_of_nat_list.simps split: if_splits )
apply(case_tac rn, auto)
apply(case_tac "rev lm1", simp, simp add: tape_of_nat_list.simps)
apply(case_tac rn, auto)
apply(case_tac list, simp_all add: tape_of_nat_list.simps, auto)
apply(case_tac "rev lm1", simp, simp add: tape_of_nat_list.simps)
apply(case_tac list, simp_all add: tape_of_nat_list.simps, auto)
done

lemma [simp]: "dec_after_write (as, am) (s, l, Bk # r) ires
       \<Longrightarrow> dec_after_write (as, am) (s', l, Oc # r) ires"
apply(auto simp: dec_after_write.simps)
done

lemma [simp]: "dec_after_write (as, am) (s, aaa, []) ires
             \<Longrightarrow> dec_after_write (as, am) (s', aaa, [Oc]) ires"
apply(auto simp: dec_after_write.simps)
done

lemma [simp]: "dec_on_right_moving (as, am) (s, l, Oc # r) ires
       \<Longrightarrow> dec_on_right_moving (as, am) (s', Oc # l, r) ires"
apply(simp only: dec_on_right_moving.simps)
apply(erule_tac exE)+
apply(erule conjE)+
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI,
      rule_tac x = "m" in exI, rule_tac x = "Suc ml" in exI, 
      rule_tac x = "mr - 1" in exI, simp)
apply(case_tac mr, auto)
done

lemma [simp]: "dec_on_right_moving (as, am) (s, l, r) ires\<Longrightarrow>  l \<noteq> []"
apply(auto simp: dec_on_right_moving.simps split: if_splits)
done

lemma [simp]: "dec_on_right_moving (as, am) (s, l, Bk # r) ires
      \<Longrightarrow>  dec_after_clear (as, am) (s', tl l, hd l # Bk # r) ires"
apply(auto simp: dec_on_right_moving.simps dec_after_clear.simps)
apply(case_tac [!] mr, auto split: if_splits)
done

lemma [simp]: "dec_on_right_moving (as, am) (s, l, []) ires
             \<Longrightarrow> dec_after_clear (as, am) (s', tl l, [hd l]) ires"
apply(auto simp: dec_on_right_moving.simps dec_after_clear.simps)
apply(case_tac mr, simp_all split: if_splits)
apply(rule_tac x = lm1 in exI, simp)
done

lemma start_of_le: "a < b \<Longrightarrow> start_of ly a \<le> start_of ly b"
proof(induct b arbitrary: a, simp, case_tac "a = b", simp)
  fix b a
  show "start_of ly b \<le> start_of ly (Suc b)"
    apply(case_tac "b::nat", 
          simp add: start_of.simps, simp add: start_of.simps)
    done
next
  fix b a
  assume h1: "\<And>a. a < b \<Longrightarrow> start_of ly a \<le> start_of ly b" 
             "a < Suc b" "a \<noteq> b"
  hence "a < b"
    by(simp)
  from h1 and this have h2: "start_of ly a \<le> start_of ly b"
    by(drule_tac h1, simp)
  from h2 show "start_of ly a \<le> start_of ly (Suc b)"
  proof -
    have "start_of ly b \<le> start_of ly (Suc b)"
      apply(case_tac "b::nat", 
            simp add: start_of.simps, simp add: start_of.simps)
      done
    from h2 and this show "start_of ly a \<le> start_of ly (Suc b)"
      by simp
  qed
qed

lemma start_of_dec_length[simp]: 
  "\<lbrakk>abc_fetch a aprog = Some (Dec n e)\<rbrakk> \<Longrightarrow> 
    start_of (layout_of aprog) (Suc a)
          = start_of (layout_of aprog) a + 2*n + 16"
apply(case_tac a, auto simp: abc_fetch.simps start_of.simps 
                             layout_of.simps length_of.simps 
                       split: if_splits)
done

lemma start_of_ge: 
 "\<lbrakk>abc_fetch a aprog = Some (Dec n e); a < e\<rbrakk> \<Longrightarrow>
  start_of (layout_of aprog) e > 
              start_of (layout_of aprog) a + 2*n + 15"
apply(case_tac "e = Suc a", 
      simp add: start_of.simps abc_fetch.simps layout_of.simps 
                length_of.simps split: if_splits)
apply(subgoal_tac "Suc a < e", drule_tac a = "Suc a" 
             and ly = "layout_of aprog" in start_of_le)
apply(subgoal_tac "start_of (layout_of aprog) (Suc a)
         = start_of (layout_of aprog) a + 2*n + 16", simp)
apply(rule_tac start_of_dec_length, simp)
apply(arith)
done

lemma starte_not_equal[simp]: 
 "\<lbrakk>abc_fetch as aprog = Some (Dec n e); ly = layout_of aprog\<rbrakk>
   \<Longrightarrow> (start_of ly e \<noteq> Suc (Suc (start_of ly as + 2 * n)) \<and>  
        start_of ly e \<noteq> start_of ly as + 2 * n + 3 \<and> 
        start_of ly e \<noteq> start_of ly as + 2 * n + 4 \<and>
        start_of ly e \<noteq> start_of ly as + 2 * n + 5 \<and> 
        start_of ly e \<noteq> start_of ly as + 2 * n + 6 \<and> 
        start_of ly e \<noteq> start_of ly as + 2 * n + 7 \<and>
        start_of ly e \<noteq> start_of ly as + 2 * n + 8 \<and> 
        start_of ly e \<noteq> start_of ly as + 2 * n + 9 \<and> 
        start_of ly e \<noteq> start_of ly as + 2 * n + 10 \<and>
        start_of ly e \<noteq> start_of ly as + 2 * n + 11 \<and> 
        start_of ly e \<noteq> start_of ly as + 2 * n + 12 \<and> 
        start_of ly e \<noteq> start_of ly as + 2 * n + 13 \<and>
        start_of ly e \<noteq> start_of ly as + 2 * n + 14 \<and> 
        start_of ly e \<noteq> start_of ly as + 2 * n + 15)" 
apply(case_tac "e = as", simp) 
apply(case_tac "e < as")
apply(drule_tac a = e and b = as and ly = ly in start_of_le, simp)
apply(drule_tac a = as and e = e in start_of_ge, simp, simp)
done

lemma [simp]: "\<lbrakk>abc_fetch as aprog = Some (Dec n e); ly = layout_of aprog\<rbrakk>
      \<Longrightarrow> (Suc (Suc (start_of ly as + 2 * n)) \<noteq> start_of ly e \<and> 
          start_of ly as + 2 * n + 3 \<noteq> start_of ly e \<and> 
          start_of ly as + 2 * n + 4 \<noteq> start_of ly e \<and>
          start_of ly as + 2 * n + 5 \<noteq>start_of ly e \<and> 
          start_of ly as + 2 * n + 6 \<noteq> start_of ly e \<and>
          start_of ly as + 2 * n + 7 \<noteq> start_of ly e \<and> 
          start_of ly as + 2 * n + 8 \<noteq> start_of ly e \<and> 
          start_of ly as + 2 * n + 9 \<noteq> start_of ly e \<and> 
          start_of ly as + 2 * n + 10 \<noteq> start_of ly e \<and>
          start_of ly as + 2 * n + 11 \<noteq> start_of ly e \<and> 
          start_of ly as + 2 * n + 12 \<noteq> start_of ly e \<and> 
          start_of ly as + 2 * n + 13 \<noteq> start_of ly e \<and> 
          start_of ly as + 2 * n + 14 \<noteq> start_of ly e \<and> 
          start_of ly as + 2 * n + 15 \<noteq> start_of ly e)"
apply(insert starte_not_equal[of as aprog n e ly], 
                            simp del: starte_not_equal)
apply(erule_tac conjE)+
apply(rule_tac conjI, simp del: starte_not_equal)+
apply(rule not_sym, simp)
done

lemma [simp]: "start_of (layout_of aprog) as > 0 \<Longrightarrow> 
  fetch (ci (layout_of aprog) (start_of (layout_of aprog) as)
                       (Dec n as)) (Suc 0) Oc =
 (R, Suc (start_of (layout_of aprog) as))"

apply(auto simp: ci.simps findnth.simps fetch.simps
                 nth_of.simps tshift.simps nth_append 
                 Suc_pre tdec_b_def)
apply(insert findnth_nth[of 0 n "Suc 0"], simp)
apply(simp add: findnth.simps)
done

lemma start_of_inj[simp]: 
  "\<lbrakk>abc_fetch as aprog = Some (Dec n e); e \<noteq> as; ly = layout_of aprog\<rbrakk>
   \<Longrightarrow> start_of ly as \<noteq> start_of ly e"
apply(case_tac "e < as")
apply(case_tac "as", simp, simp)
apply(case_tac "e = nat", simp add: start_of.simps 
                                    layout_of.simps length_of.simps)
apply(subgoal_tac "e < length aprog", simp add: length_of.simps 
                                         split: abc_inst.splits)
apply(simp add: abc_fetch.simps split: if_splits)
apply(subgoal_tac "e < nat", drule_tac a = e and b = nat 
                                   and ly =ly in start_of_le, simp)
apply(subgoal_tac "start_of ly nat < start_of ly (Suc nat)", 
          simp, simp add: start_of.simps layout_of.simps)
apply(subgoal_tac "nat < length aprog", simp)
apply(case_tac "aprog ! nat", auto simp: length_of.simps)
apply(simp add: abc_fetch.simps split: if_splits)
apply(subgoal_tac "e > as", drule_tac start_of_ge, auto)
done

lemma [simp]: "\<lbrakk>abc_fetch as aprog = Some (Dec n e); e < as\<rbrakk>
    \<Longrightarrow> Suc (start_of (layout_of aprog) e) - 
                               start_of (layout_of aprog) as = 0"
apply(frule_tac ly = "layout_of aprog" in start_of_le, simp)
apply(subgoal_tac "start_of (layout_of aprog) as \<noteq> 
                            start_of (layout_of aprog) e", arith)
apply(rule start_of_inj, auto)
done

lemma [simp]:
   "\<lbrakk>abc_fetch as aprog = Some (Dec n e); 
     0 < start_of (layout_of aprog) as\<rbrakk>
 \<Longrightarrow> (fetch (ci (layout_of aprog) (start_of (layout_of aprog) as) 
     (Dec n e)) (Suc (start_of (layout_of aprog) e) - 
                 start_of (layout_of aprog) as) Oc)
    = (if e = as then (R, start_of (layout_of aprog) as + 1)
                 else (Nop, 0))"
apply(auto split: if_splits)
apply(case_tac "e < as", simp add: fetch.simps)
apply(subgoal_tac " e > as")
apply(drule start_of_ge, simp,
      auto simp: fetch.simps ci_length nth_of.simps)
apply(subgoal_tac 
 "length (ci (layout_of aprog) (start_of (layout_of aprog) as) 
                        (Dec n e)) div 2= length_of (Dec n e)")
defer
apply(simp add: ci_length)
apply(subgoal_tac 
 "length (ci (layout_of aprog) (start_of (layout_of aprog) as)
                  (Dec n e)) mod 2 = 0", auto simp: length_of.simps)
done

lemma [simp]:
    "start_of (layout_of aprog) as > 0 \<Longrightarrow> 
 fetch (ci (layout_of aprog) (start_of (layout_of aprog) as) 
                                          (Dec n as)) (Suc 0)  Bk 
      = (W1, start_of (layout_of aprog) as)"
apply(auto simp: ci.simps findnth.simps fetch.simps nth_of.simps 
                 tshift.simps nth_append Suc_pre tdec_b_def)
apply(insert findnth_nth[of 0 n "0"], simp)
apply(simp add: findnth.simps)
done

lemma [simp]: 
 "\<lbrakk>abc_fetch as aprog = Some (Dec n e); 
   0 < start_of (layout_of aprog) as\<rbrakk>
\<Longrightarrow> (fetch (ci (layout_of aprog) (start_of (layout_of aprog) as)
         (Dec n e)) (Suc (start_of (layout_of aprog) e) - 
              start_of (layout_of aprog) as)  Bk)
   = (if e = as then (W1, start_of (layout_of aprog) as)
                  else (Nop, 0))"
apply(auto split: if_splits)
apply(case_tac "e < as", simp add: fetch.simps)
apply(subgoal_tac " e > as")
apply(drule start_of_ge, simp, auto simp: fetch.simps 
                                          ci_length nth_of.simps)
apply(subgoal_tac 
 "length (ci (layout_of aprog) (start_of (layout_of aprog) as) 
                            (Dec n e)) div 2= length_of (Dec n e)")
defer
apply(simp add: ci_length)
apply(subgoal_tac 
 "length (ci (layout_of aprog) (start_of (layout_of aprog) as) 
                   (Dec n e)) mod 2 = 0", auto simp: length_of.simps)
apply(simp add: ci.simps tshift.simps tdec_b_def)
done

lemma [simp]: 
 "inv_stop (as, abc_lm_s am n (abc_lm_v am n)) (s, l, r) ires \<Longrightarrow> l \<noteq> []"
apply(auto simp: inv_stop.simps)
done

lemma [simp]: 
 "\<lbrakk>abc_fetch as aprog = Some (Dec n e); e \<noteq> as; ly = layout_of aprog\<rbrakk>
  \<Longrightarrow> (\<not> (start_of ly as \<le> start_of ly e \<and> 
      start_of ly e < start_of ly as + 2 * n))
    \<and> start_of ly e \<noteq> start_of ly as + 2*n \<and> 
      start_of ly e \<noteq> Suc (start_of ly as + 2*n) "
apply(case_tac "e < as")
apply(drule_tac ly = ly in start_of_le, simp)
apply(case_tac n, simp, drule start_of_inj, simp, simp, simp, simp)
apply(drule_tac start_of_ge, simp, simp)
done

lemma [simp]: 
   "\<lbrakk>abc_fetch as aprog = Some (Dec n e); start_of ly as \<le> s; 
     s < start_of ly as + 2 * n; ly = layout_of aprog\<rbrakk>
     \<Longrightarrow> Suc s \<noteq> start_of ly e "
apply(case_tac "e = as", simp)
apply(case_tac "e < as")
apply(drule_tac a = e and b = as and ly = ly in start_of_le, simp)
apply(drule_tac start_of_ge, auto)
done

lemma [simp]: "\<lbrakk>abc_fetch as aprog = Some (Dec n e); 
                ly = layout_of aprog\<rbrakk>
         \<Longrightarrow> Suc (start_of ly as + 2 * n) \<noteq> start_of ly e"
apply(case_tac "e = as", simp)
apply(case_tac "e < as")
apply(drule_tac a = e and b = as and ly = ly in start_of_le, simp)
apply(drule_tac start_of_ge, auto)
done

lemma dec_false_1[simp]:
 "\<lbrakk>abc_lm_v am n = 0; inv_locate_b (as, am) (n, aaa, Oc # xs) ires\<rbrakk>
  \<Longrightarrow> False"
apply(auto simp: inv_locate_b.simps in_middle.simps exponent_def)
apply(case_tac "length lm1 \<ge> length am", auto)
apply(subgoal_tac "lm2 = []", simp, subgoal_tac "m = 0", simp)
apply(case_tac mr, auto simp: )
apply(subgoal_tac "Suc (length lm1) - length am = 
                   Suc (length lm1 - length am)", 
      simp add: rep_ind del: replicate.simps, simp)
apply(drule_tac xs = "am @ replicate (Suc (length lm1) - length am) 0"
                and ys = "lm1 @ m # lm2" in length_equal, simp)
apply(case_tac mr, auto simp: abc_lm_v.simps)
apply(case_tac "mr = 0", simp_all add:  exponent_def split: if_splits)
apply(subgoal_tac "Suc (length lm1) - length am = 
                       Suc (length lm1 - length am)", 
      simp add: rep_ind del: replicate.simps, simp)
done

lemma [simp]: 
 "\<lbrakk>inv_locate_b (as, am) (n, aaa, Bk # xs) ires; 
   abc_lm_v am n = 0\<rbrakk>
   \<Longrightarrow> inv_on_left_moving (as, abc_lm_s am n 0) 
                         (s, tl aaa, hd aaa # Bk # xs) ires" 
apply(insert inv_locate_b_2_on_left_moving[of as am n aaa xs ires s], simp)
done

lemma [simp]:
 "\<lbrakk>abc_lm_v am n = 0; inv_locate_b (as, am) (n, aaa, []) ires\<rbrakk>
   \<Longrightarrow> inv_on_left_moving (as, abc_lm_s am n 0) (s, tl aaa, [hd aaa]) ires"
apply(insert inv_locate_b_2_on_left_moving_b[of as am n aaa ires s], simp)
done

lemma [simp]: "\<lbrakk>am ! n = (0::nat); n < length am\<rbrakk> \<Longrightarrow> am[n := 0] = am"
apply(simp add: list_update_same_conv)
done

lemma [simp]: "\<lbrakk>abc_lm_v am n = 0; 
                inv_locate_b (as, abc_lm_s am n 0) (n, Oc # aaa, xs) ires\<rbrakk>
     \<Longrightarrow> inv_locate_b (as, am) (n, Oc # aaa, xs) ires"
apply(simp only: inv_locate_b.simps in_middle.simps abc_lm_s.simps 
                 abc_lm_v.simps)
apply(erule_tac exE)+
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, simp)
apply(case_tac "n < length am", simp_all)
apply(erule_tac conjE)+
apply(rule_tac x = tn in exI, rule_tac x = m in exI, simp)
apply(rule_tac x = ml in exI, rule_tac x = mr in exI, simp)
defer
apply(rule_tac x = "Suc n - length am" in exI, rule_tac x = m in exI)
apply(subgoal_tac "Suc n - length am = Suc (n - length am)")
apply(simp add: exponent_def rep_ind del: replicate.simps, auto)
done

lemma  [intro]: "\<lbrakk>abc_lm_v (a # list) 0 = 0\<rbrakk> \<Longrightarrow> a = 0"
apply(simp add: abc_lm_v.simps split: if_splits)
done

lemma [simp]: 
 "inv_stop (as, abc_lm_s am n 0) 
          (start_of (layout_of aprog) e, aaa, Oc # xs) ires
  \<Longrightarrow> inv_locate_a (as, abc_lm_s am n 0) (0, aaa, Oc # xs) ires"
apply(simp add: inv_locate_a.simps)
apply(rule disjI1)
apply(auto simp: inv_stop.simps at_begin_norm.simps)
done

lemma [simp]: 
 "\<lbrakk>abc_lm_v am 0 = 0; 
  inv_stop (as, abc_lm_s am 0 0) 
      (start_of (layout_of aprog) e, aaa, Oc # xs) ires\<rbrakk> \<Longrightarrow> 
  inv_locate_b (as, am) (0, Oc # aaa, xs) ires"
apply(auto simp: inv_stop.simps inv_locate_b.simps 
                 in_middle.simps abc_lm_s.simps)
apply(case_tac "am = []", simp)
apply(rule_tac x = "[]" in exI, rule_tac x = "Suc 0" in exI, 
      rule_tac x = 0 in exI, simp)
apply(rule_tac x = "Suc 0" in exI, rule_tac x = 0 in exI, 
  simp add: tape_of_nl_abv tape_of_nat_list.simps, auto)
apply(case_tac rn, auto)
apply(rule_tac x = "tl am" in exI, rule_tac x = 0 in exI, 
      rule_tac x = "hd am" in exI, simp)
apply(rule_tac x = "Suc 0" in exI, rule_tac x = "hd am" in exI, simp)
apply(case_tac am, simp, simp)
apply(subgoal_tac "a = 0", case_tac list, 
      auto simp: tape_of_nat_list.simps tape_of_nl_abv)
apply(case_tac rn, auto)
done

lemma [simp]: 
 "\<lbrakk>inv_stop (as, abc_lm_s am n 0) 
          (start_of (layout_of aprog) e, aaa, Oc # xs) ires\<rbrakk>
  \<Longrightarrow> inv_locate_b (as, am) (0, Oc # aaa, xs) ires \<or> 
      inv_locate_b (as, abc_lm_s am n 0) (0, Oc # aaa, xs) ires"
apply(simp)
done

lemma [simp]: 
"\<lbrakk>abc_lm_v am n = 0; 
  inv_stop (as, abc_lm_s am n 0) 
          (start_of (layout_of aprog) e, aaa, Oc # xs) ires\<rbrakk>
 \<Longrightarrow> \<not> Suc 0 < 2 * n \<longrightarrow> e = as \<longrightarrow> 
            inv_locate_b (as, am) (n, Oc # aaa, xs) ires"
apply(case_tac n, simp, simp)
done

lemma dec_false2: 
 "inv_stop (as, abc_lm_s am n 0) 
  (start_of (layout_of aprog) e, aaa, Bk # xs) ires = False"
apply(auto simp: inv_stop.simps abc_lm_s.simps)
apply(case_tac "am", simp, case_tac n, simp add: tape_of_nl_abv)
apply(case_tac list, simp add: tape_of_nat_list.simps )
apply(simp add: tape_of_nat_list.simps , simp)
apply(case_tac "list[nat := 0]", 
      simp add: tape_of_nat_list.simps  tape_of_nl_abv)
apply(simp add: tape_of_nat_list.simps )
apply(case_tac "am @ replicate (n - length am) 0 @ [0]", simp)
apply(case_tac list, auto simp: tape_of_nl_abv 
                                tape_of_nat_list.simps )
done	

lemma dec_false3:
   "inv_stop (as, abc_lm_s am n 0) 
              (start_of (layout_of aprog) e, aaa, []) ires = False"
apply(auto simp: inv_stop.simps abc_lm_s.simps)
apply(case_tac "am", case_tac n, auto)
apply(case_tac n, auto simp: tape_of_nl_abv)
apply(case_tac "list::nat list",
            simp add: tape_of_nat_list.simps tape_of_nat_list.simps)
apply(simp add: tape_of_nat_list.simps)
apply(case_tac "list[nat := 0]", 
            simp add: tape_of_nat_list.simps tape_of_nat_list.simps)
apply(simp add: tape_of_nat_list.simps)
apply(case_tac "(am @ replicate (n - length am) 0 @ [0])", simp)
apply(case_tac list, auto simp: tape_of_nat_list.simps)
done

lemma [simp]:
  "fetch (ci (layout_of aprog) 
       (start_of (layout_of aprog) as) (Dec n e)) 0 b = (Nop, 0)"
by(simp add: fetch.simps)

declare dec_inv_1.simps[simp del]

declare inv_locate_n_b.simps [simp del]

lemma [simp]:
"\<lbrakk>0 < abc_lm_v am n; 0 < n; 
  at_begin_norm (as, am) (n, aaa, Oc # xs) ires\<rbrakk>
  \<Longrightarrow> inv_locate_n_b (as, am) (n, Oc # aaa, xs) ires"
apply(simp only: at_begin_norm.simps inv_locate_n_b.simps)
apply(erule_tac exE)+
apply(rule_tac x = lm1 in exI, simp)
apply(case_tac "length lm2", simp)
apply(case_tac rn, simp, simp)
apply(rule_tac x = "tl lm2" in exI, rule_tac x = "hd lm2" in exI, simp)
apply(rule conjI)
apply(case_tac "lm2", simp, simp)
apply(case_tac "lm2", auto simp: tape_of_nl_abv tape_of_nat_list.simps)
apply(case_tac [!] "list", auto simp: tape_of_nl_abv tape_of_nat_list.simps)
apply(case_tac rn, auto)
done 
lemma [simp]: "(\<exists>rn. Oc # xs = Bk\<^bsup>rn\<^esup>) = False"
apply(auto)
apply(case_tac rn, auto simp: )
done

lemma [simp]:
  "\<lbrakk>0 < abc_lm_v am n; 0 < n; 
    at_begin_fst_bwtn (as, am) (n, aaa, Oc # xs) ires\<rbrakk>
 \<Longrightarrow> inv_locate_n_b (as, am) (n, Oc # aaa, xs) ires"
apply(simp add: at_begin_fst_bwtn.simps inv_locate_n_b.simps )
done
 
lemma Suc_minus:"length am + tn = n
       \<Longrightarrow> Suc tn = Suc n - length am "
apply(arith)
done

lemma [simp]: 
 "\<lbrakk>0 < abc_lm_v am n; 0 < n; 
   at_begin_fst_awtn (as, am) (n, aaa, Oc # xs) ires\<rbrakk>
 \<Longrightarrow> inv_locate_n_b (as, am) (n, Oc # aaa, xs) ires"
apply(simp only: at_begin_fst_awtn.simps inv_locate_n_b.simps )
apply(erule exE)+
apply(erule conjE)+
apply(rule_tac x = lm1 in exI, rule_tac x = "[]" in exI, 
      rule_tac x = "Suc tn" in exI, rule_tac x = 0 in exI)
apply(simp add: exponent_def rep_ind del: replicate.simps)
apply(rule conjI)+
apply(auto)
apply(case_tac [!] rn, auto)
done

lemma [simp]: 
 "\<lbrakk>0 < abc_lm_v am n; 0 < n; inv_locate_a (as, am) (n, aaa, Oc # xs) ires\<rbrakk>
 \<Longrightarrow> inv_locate_n_b (as, am) (n, Oc#aaa, xs) ires"
apply(auto simp: inv_locate_a.simps)
done

lemma [simp]:
 "\<lbrakk>inv_locate_n_b (as, am) (n, aaa, Oc # xs) ires\<rbrakk>
 \<Longrightarrow> dec_first_on_right_moving n (as, abc_lm_s am n (abc_lm_v am n))  
                                      (s, Oc # aaa, xs) ires"
apply(auto simp: inv_locate_n_b.simps dec_first_on_right_moving.simps 
                 abc_lm_s.simps abc_lm_v.simps)
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = m in exI, simp)
apply(rule_tac x = "Suc (Suc 0)" in exI, 
      rule_tac x = "m - 1" in exI, simp)
apply(case_tac m, auto simp:  exponent_def)
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = m in exI, 
      simp add: Suc_diff_le rep_ind del: replicate.simps)
apply(rule_tac x = "Suc (Suc 0)" in exI, 
      rule_tac x = "m - 1" in exI, simp)
apply(case_tac m, auto simp:  exponent_def)
apply(rule_tac x = lm1 in exI, rule_tac x = "[]" in exI, 
      rule_tac x = m in exI, simp)
apply(rule_tac x = "Suc (Suc 0)" in exI, 
      rule_tac x = "m - 1" in exI, simp)
apply(case_tac m, auto)
apply(rule_tac x = lm1 in exI, rule_tac x = lm2 in exI, 
      rule_tac x = m in exI, 
      simp add: Suc_diff_le rep_ind del: replicate.simps, simp)
done

lemma dec_false_2: 
 "\<lbrakk>0 < abc_lm_v am n; inv_locate_n_b (as, am) (n, aaa, Bk # xs) ires\<rbrakk> 
 \<Longrightarrow> False"
apply(auto simp: inv_locate_n_b.simps abc_lm_v.simps split: if_splits)
apply(case_tac [!] m, auto)
done
 
lemma dec_false_2_b:
 "\<lbrakk>0 < abc_lm_v am n; inv_locate_n_b (as, am) 
                                (n, aaa, []) ires\<rbrakk> \<Longrightarrow> False"
apply(auto simp: inv_locate_n_b.simps abc_lm_v.simps split: if_splits)
apply(case_tac [!] m, auto simp: )
done


(*begin: dec halt1 lemmas*)
thm abc_inc_stage1.simps
fun abc_dec_1_stage1:: "t_conf \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> nat"
  where
  "abc_dec_1_stage1 (s, l, r) ss n = 
       (if s > ss \<and> s \<le> ss + 2*n + 1 then 4
        else if s = ss + 2 * n + 13 \<or> s = ss + 2*n + 14 then 3
        else if s = ss + 2*n + 15 then 2
        else 0)"

fun abc_dec_1_stage2:: "t_conf \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> nat"
  where
  "abc_dec_1_stage2 (s, l, r) ss n = 
       (if s \<le> ss + 2 * n + 1 then (ss + 2 * n + 16 - s)
        else if s = ss + 2*n + 13 then length l
        else if s = ss + 2*n + 14 then length l
        else 0)"

fun abc_dec_1_stage3 :: "t_conf \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> block list \<Rightarrow> nat"
  where
  "abc_dec_1_stage3 (s, l, r) ss n ires = 
        (if s \<le> ss + 2*n + 1 then 
             if (s - ss) mod 2 = 0 then 
                         if r \<noteq> [] \<and> hd r = Oc then 0 else 1  
                         else length r
         else if s = ss + 2 * n + 13 then 
             if l = Bk # ires \<and> r \<noteq> [] \<and> hd r = Oc then 2 
             else 1
         else if s = ss + 2 * n + 14 then 
             if r \<noteq> [] \<and> hd r = Oc then 3 else 0 
         else 0)"

fun abc_dec_1_measure :: "(t_conf \<times> nat \<times> nat \<times> block list) \<Rightarrow> (nat \<times> nat \<times> nat)"
  where
  "abc_dec_1_measure (c, ss, n, ires) = (abc_dec_1_stage1 c ss n, 
                   abc_dec_1_stage2 c ss n, abc_dec_1_stage3 c ss n ires)"

definition abc_dec_1_LE ::
  "(((nat \<times> block list \<times> block list) \<times> nat \<times>
  nat \<times> block list) \<times> ((nat \<times> block list \<times> block list) \<times> nat \<times> nat \<times> block list)) set"
  where "abc_dec_1_LE \<equiv> (inv_image lex_triple abc_dec_1_measure)"

lemma wf_dec_le: "wf abc_dec_1_LE"
by(auto intro:wf_inv_image wf_lex_triple simp:abc_dec_1_LE_def)

declare dec_inv_1.simps[simp del] dec_inv_2.simps[simp del]

lemma [elim]: 
 "\<lbrakk>abc_fetch as aprog = Some (Dec n e); 
   start_of (layout_of aprog) as < start_of (layout_of aprog) e;
   start_of (layout_of aprog) e \<le> 
         Suc (start_of (layout_of aprog) as + 2 * n)\<rbrakk> \<Longrightarrow> False"
apply(case_tac "e = as", simp)
apply(case_tac "e < as")
apply(drule_tac a = e and b = as and ly = "layout_of aprog" in 
                                                 start_of_le, simp)
apply(drule_tac start_of_ge, auto)
done

lemma [elim]: "\<lbrakk>abc_fetch as aprog = Some (Dec n e); 
                                start_of (layout_of aprog) e 
    = start_of (layout_of aprog) as + 2 * n + 13\<rbrakk>
         \<Longrightarrow> False"
apply(insert starte_not_equal[of as aprog n e "layout_of aprog"], 
      simp)
done

lemma [elim]: "\<lbrakk>abc_fetch as aprog = Some (Dec n e);
                 start_of (layout_of aprog) e = 
               start_of (layout_of aprog) as + 2 * n + 14\<rbrakk>
        \<Longrightarrow> False"
apply(insert starte_not_equal[of as aprog n e "layout_of aprog"],
      simp)
done

lemma [elim]: 
 "\<lbrakk>abc_fetch as aprog = Some (Dec n e);
   start_of (layout_of aprog) as < start_of (layout_of aprog) e;
   start_of (layout_of aprog) e \<le> 
              Suc (start_of (layout_of aprog) as + 2 * n)\<rbrakk>
   \<Longrightarrow> False"
apply(case_tac "e = as", simp)
apply(case_tac "e < as")
apply(drule_tac a = e and b = as and ly = "layout_of aprog" in 
                                                    start_of_le, simp)
apply(drule_tac start_of_ge, auto)
done

lemma [elim]: 
 "\<lbrakk>abc_fetch as aprog = Some (Dec n e); 
   start_of (layout_of aprog) e = 
               start_of (layout_of aprog) as + 2 * n + 13\<rbrakk>
    \<Longrightarrow> False"
apply(insert starte_not_equal[of as aprog n e "layout_of aprog"], 
      simp)
done

lemma [simp]: 
 "abc_fetch as aprog = Some (Dec n e) \<Longrightarrow> 
   Suc (start_of (layout_of aprog) as) \<noteq> start_of (layout_of aprog) e"
apply(case_tac "e = as", simp) 
apply(case_tac "e < as")
apply(drule_tac a = e and b = as and ly = "(layout_of aprog)" in 
                                                 start_of_le, simp)
apply(drule_tac a = as and e = e in start_of_ge, simp, simp)
done

lemma [simp]: "inv_on_left_moving (as, am) (s, [], r) ires 
  = False"
apply(simp add: inv_on_left_moving.simps inv_on_left_moving_norm.simps
                inv_on_left_moving_in_middle_B.simps)
done

lemma [simp]: 
  "inv_check_left_moving (as, abc_lm_s am n 0)
  (start_of (layout_of aprog) as + 2 * n + 14, [], Oc # xs) ires
 = False"
apply(simp add: inv_check_left_moving.simps inv_check_left_moving_in_middle.simps)
done

lemma dec_inv_stop1_pre: 
    "\<lbrakk>abc_fetch as aprog = Some (Dec n e); abc_lm_v am n = 0;
      start_of (layout_of aprog) as > 0\<rbrakk>
 \<Longrightarrow> \<forall>na. \<not> (\<lambda>(s, l, r) (ss, n', ires'). s = start_of (layout_of aprog) e)
            (t_steps (Suc (start_of (layout_of aprog) as), l, r) 
              (ci (layout_of aprog) (start_of (layout_of aprog) as) 
                 (Dec n e), start_of (layout_of aprog) as - Suc 0) na)
                      (start_of (layout_of aprog) as, n, ires) \<and>
           dec_inv_1 (layout_of aprog) n e (as, am)
            (t_steps (Suc (start_of (layout_of aprog) as), l, r) 
              (ci (layout_of aprog) (start_of (layout_of aprog) as) 
                (Dec n e), start_of (layout_of aprog) as - Suc 0) na) ires
       \<longrightarrow> dec_inv_1 (layout_of aprog) n e (as, am)
            (t_steps (Suc (start_of (layout_of aprog) as), l, r) 
              (ci (layout_of aprog) (start_of (layout_of aprog) as)
                 (Dec n e), start_of (layout_of aprog) as - Suc 0) 
                    (Suc na)) ires \<and>
            ((t_steps (Suc (start_of (layout_of aprog) as), l, r) 
            (ci (layout_of aprog) (start_of (layout_of aprog) as) 
           (Dec n e), start_of (layout_of aprog) as - Suc 0) (Suc na),
             start_of (layout_of aprog) as, n, ires),
         t_steps (Suc (start_of (layout_of aprog) as), l, r) 
            (ci (layout_of aprog) (start_of (layout_of aprog) as) 
               (Dec n e), start_of (layout_of aprog) as - Suc 0) na,
            start_of (layout_of aprog) as, n, ires)
           \<in> abc_dec_1_LE"
apply(rule allI, rule impI, simp add: t_steps_ind)
apply(case_tac "(t_steps (Suc (start_of (layout_of aprog) as), l, r) 
(ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), 
start_of (layout_of aprog) as - Suc 0) na)", simp)
apply(auto split:if_splits simp add:t_step.simps dec_inv_1.simps, 
          tactic {* ALLGOALS (resolve_tac [@{thm fetch_intro}]) *})
apply(simp_all add:dec_fetch_simps new_tape.simps dec_inv_1.simps)
apply(auto simp add: abc_dec_1_LE_def lex_square_def 
                     lex_triple_def lex_pair_def  
                split: if_splits)
apply(rule dec_false_1, simp, simp)
done

lemma dec_inv_stop1: 
  "\<lbrakk>ly = layout_of aprog; 
    dec_inv_1 ly n e (as, am) (start_of ly as + 1, l, r) ires; 
    abc_fetch as aprog = Some (Dec n e); abc_lm_v am n = 0\<rbrakk> \<Longrightarrow> 
  (\<exists> stp. (\<lambda> (s', l', r'). s' = start_of ly e \<and> 
           dec_inv_1 ly n e (as, am) (s', l' , r') ires) 
  (t_steps (start_of ly as + 1, l, r)
     (ci ly (start_of ly as) (Dec n e), start_of ly as - Suc 0) stp))"
apply(insert halt_lemma2[of abc_dec_1_LE 
    "\<lambda> ((s, l, r), ss, n', ires'). s = start_of ly e" 
     "(\<lambda> stp. (t_steps (start_of ly as + 1, l, r) 
          (ci ly (start_of ly as) (Dec n e), start_of ly as - Suc 0) 
               stp, start_of ly as, n, ires))"
     "\<lambda> ((s, l, r), ss, n, ires'). dec_inv_1 ly n e (as, am) (s, l, r) ires'"],
     simp)
apply(insert wf_dec_le, simp)
apply(insert dec_inv_stop1_pre[of as aprog n e am l r], simp)
apply(subgoal_tac "start_of (layout_of aprog) as > 0", 
                                      simp add: t_steps.simps)
apply(erule_tac exE, rule_tac x = na in exI)
apply(case_tac
     "(t_steps (Suc (start_of (layout_of aprog) as), l, r) 
         (ci (layout_of aprog) (start_of (layout_of aprog) as)
           (Dec n e), start_of (layout_of aprog) as - Suc 0) na)",
      case_tac b, auto)
apply(rule startof_not0)
done

(*begin: dec halt2 lemmas*)

lemma [simp]:
  "\<lbrakk>abc_fetch as aprog = Some (Dec n e); 
    ly = layout_of aprog\<rbrakk> \<Longrightarrow> 
              start_of ly (Suc as) = start_of ly as + 2*n + 16"
by simp

fun abc_dec_2_stage1 :: "t_conf \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> nat"
  where
  "abc_dec_2_stage1 (s, l, r) ss n = 
              (if s \<le> ss + 2*n + 1 then 7
               else if s = ss + 2*n + 2 then 6 
               else if s = ss + 2*n + 3 then 5
               else if s \<ge> ss + 2*n + 4 \<and> s \<le> ss + 2*n + 9 then 4
               else if s = ss + 2*n + 6 then 3
               else if s = ss + 2*n + 10 \<or> s = ss + 2*n + 11 then 2
               else if s = ss + 2*n + 12 then 1
               else 0)"

thm new_tape.simps

fun abc_dec_2_stage2 :: "t_conf \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> nat"
  where
  "abc_dec_2_stage2 (s, l, r) ss n = 
       (if s \<le> ss + 2 * n + 1 then (ss + 2 * n + 16 - s)
        else if s = ss + 2*n + 10 then length l
        else if s = ss + 2*n + 11 then length l
        else if s = ss + 2*n + 4 then length r - 1
        else if s = ss + 2*n + 5 then length r 
        else if s = ss + 2*n + 7 then length r - 1
        else if s = ss + 2*n + 8 then  
              length r + length (takeWhile (\<lambda> a. a = Oc) l) - 1
        else if s = ss + 2*n + 9 then 
              length r + length (takeWhile (\<lambda> a. a = Oc) l) - 1
        else 0)"

fun abc_dec_2_stage3 :: "t_conf \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> block list \<Rightarrow> nat"
  where
  "abc_dec_2_stage3 (s, l, r) ss n ires =
        (if s \<le> ss + 2*n + 1 then 
            if (s - ss) mod 2 = 0 then if r \<noteq> [] \<and> 
                                          hd r = Oc then 0 else 1  
            else length r
         else if s = ss + 2 * n + 10 then 
             if l = Bk # ires \<and> r \<noteq> [] \<and> hd r = Oc then 2
             else 1
         else if s = ss + 2 * n + 11 then 
             if r \<noteq> [] \<and> hd r = Oc then 3 
             else 0 
         else (ss + 2 * n + 16 - s))"

fun abc_dec_2_stage4 :: "t_conf \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> nat"
  where
  "abc_dec_2_stage4 (s, l, r) ss n = 
          (if s = ss + 2*n + 2 then length r
           else if s = ss + 2*n + 8 then length r
           else if s = ss + 2*n + 3 then 
               if r \<noteq> [] \<and> hd r = Oc then 1
               else 0
           else if s = ss + 2*n + 7 then 
               if r \<noteq> [] \<and> hd r = Oc then 0 
               else 1
           else if s = ss + 2*n + 9 then 
               if r \<noteq> [] \<and> hd r = Oc then 1
               else 0 
           else 0)"

fun abc_dec_2_measure :: "(t_conf \<times> nat \<times> nat \<times> block list) \<Rightarrow> 
                                    (nat \<times> nat \<times> nat \<times> nat)"
  where
  "abc_dec_2_measure (c, ss, n, ires) = 
       (abc_dec_2_stage1 c ss n, abc_dec_2_stage2 c ss n,
        abc_dec_2_stage3 c ss n ires, abc_dec_2_stage4 c ss n)"

definition abc_dec_2_LE :: 
       "(((nat \<times> block list \<times> block list) \<times> nat \<times> nat \<times> block list) \<times> 
        ((nat \<times> block list \<times> block list) \<times> nat \<times> nat \<times> block list)) set"
  where "abc_dec_2_LE \<equiv> (inv_image lex_square abc_dec_2_measure)"

lemma wf_dec_2_le: "wf abc_dec_2_LE"
by(auto intro:wf_inv_image wf_lex_triple wf_lex_square 
   simp:abc_dec_2_LE_def)

lemma [simp]: "dec_after_write (as, am) (s, aa, r) ires
           \<Longrightarrow> takeWhile (\<lambda>a. a = Oc) aa = []"
apply(simp only : dec_after_write.simps)
apply(erule exE)+
apply(erule_tac conjE)+
apply(case_tac aa, simp)
apply(case_tac a, simp only: takeWhile.simps , simp, simp split: if_splits)
done

lemma [simp]: 
     "\<lbrakk>dec_on_right_moving (as, lm) (s, aa, []) ires; 
       length (takeWhile (\<lambda>a. a = Oc) (tl aa)) 
           \<noteq> length (takeWhile (\<lambda>a. a = Oc) aa) - Suc 0\<rbrakk>
    \<Longrightarrow> length (takeWhile (\<lambda>a. a = Oc) (tl aa)) < 
                       length (takeWhile (\<lambda>a. a = Oc) aa) - Suc 0"
apply(simp only: dec_on_right_moving.simps)
apply(erule_tac exE)+
apply(erule_tac conjE)+
apply(case_tac mr, auto split: if_splits)
done

lemma [simp]: 
  "dec_after_clear (as, abc_lm_s am n (abc_lm_v am n - Suc 0)) 
             (start_of (layout_of aprog) as + 2 * n + 9, aa, Bk # xs) ires
 \<Longrightarrow> length xs - Suc 0 < length xs + 
                             length (takeWhile (\<lambda>a. a = Oc) aa)"
apply(simp only: dec_after_clear.simps)
apply(erule_tac exE)+
apply(erule conjE)+
apply(simp split: if_splits )
done

lemma [simp]: 
 "\<lbrakk>dec_after_clear (as, abc_lm_s am n (abc_lm_v am n - Suc 0))
       (start_of (layout_of aprog) as + 2 * n + 9, aa, []) ires\<rbrakk>
    \<Longrightarrow> Suc 0 < length (takeWhile (\<lambda>a. a = Oc) aa)"
apply(simp add: dec_after_clear.simps split: if_splits)
done

lemma [simp]: 
 "\<lbrakk>dec_on_right_moving (as, am) (s, aa, Bk # xs) ires; 
   Suc (length (takeWhile (\<lambda>a. a = Oc) (tl aa)))
   \<noteq> length (takeWhile (\<lambda>a. a = Oc) aa)\<rbrakk>
  \<Longrightarrow> Suc (length (takeWhile (\<lambda>a. a = Oc) (tl aa))) 
    < length (takeWhile (\<lambda>a. a = Oc) aa)"
apply(simp only: dec_on_right_moving.simps)
apply(erule exE)+
apply(erule conjE)+
apply(case_tac ml, auto split: if_splits )
done

(*
lemma abc_dec_2_wf: 
     "\<lbrakk>ly = layout_of aprog; dec_inv_2 ly n e (as, am) (start_of ly as + 1, l, r);  abc_fetch as aprog = Dec n e; abc_lm_v am n > 0\<rbrakk>
       \<Longrightarrow> \<forall>na. \<not> (\<lambda>(s, l, r) (ss, n'). s = start_of (layout_of aprog) as + 2*n + 16)
        (t_steps (Suc (start_of (layout_of aprog) as), l, r) (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), start_of (layout_of aprog) as - Suc 0) na)
           (start_of (layout_of aprog) as, n) \<longrightarrow>
        ((t_steps (Suc (start_of (layout_of aprog) as), l, r) (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), start_of (layout_of aprog) as - Suc 0) (Suc na),
            start_of (layout_of aprog) as, n),
          t_steps (Suc (start_of (layout_of aprog) as), l, r) (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), start_of (layout_of aprog) as - Suc 0) na,
           start_of (layout_of aprog) as, n)
        \<in> abc_dec_2_LE"
proof(rule allI, rule impI, simp add: t_steps_ind)
  fix na
  assume h1 :"ly = layout_of aprog" "dec_inv_2 (layout_of aprog) n e (as, am) (Suc (start_of (layout_of aprog) as), l, r)" 
          "abc_fetch as aprog = Dec n e" "abc_lm_v am n > 0"
         "\<not> (\<lambda>(s, l, r) (ss, n'). s = start_of (layout_of aprog) as + 2*n + 16)
             (t_steps (Suc (start_of (layout_of aprog) as), l, r) (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), start_of (layout_of aprog) as - Suc 0) na)
             (start_of (layout_of aprog) as, n)"
  thus "((t_step (t_steps (Suc (start_of (layout_of aprog) as), l, r) (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), start_of (layout_of aprog) as - Suc 0) na)
               (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), start_of (layout_of aprog) as - Suc 0),
              start_of (layout_of aprog) as, n),
             t_steps (Suc (start_of (layout_of aprog) as), l, r) (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), start_of (layout_of aprog) as - Suc 0) na,
             start_of (layout_of aprog) as, n)
            \<in> abc_dec_2_LE"
  proof(insert dec_inv_2_steps[of "layout_of aprog" n e as am "(start_of (layout_of aprog) as + 1, l, r)" aprog na], 
        case_tac "(t_steps (start_of (layout_of aprog) as + 1, l, r) (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), start_of (layout_of aprog) as - Suc 0) na)", case_tac b, simp)
    fix a b aa ba
    assume "dec_inv_2 (layout_of aprog) n e (as, am) (a, aa, ba)" " a \<noteq> start_of (layout_of aprog) as + 2*n + 16" "abc_lm_v am n > 0" "abc_fetch as aprog = Dec n e "
    thus "((t_step (a, aa, ba) (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), start_of (layout_of aprog) as - Suc 0), start_of (layout_of aprog) as, n), (a, aa, ba),
                    start_of (layout_of aprog) as, n)
                   \<in> abc_dec_2_LE"
      apply(case_tac "a = 0", auto split:if_splits simp add:t_step.simps dec_inv_2.simps, 
                tactic {* ALLGOALS (resolve_tac (thms "fetch_intro")) *})
      apply(simp_all add:dec_fetch_simps new_tape.simps)
      apply(auto simp add: abc_dec_2_LE_def  lex_square_def lex_triple_def lex_pair_def  
                           split: if_splits)
      
      done
  qed
qed
*)

lemma [simp]: "inv_check_left_moving (as, abc_lm_s am n (abc_lm_v am n - Suc 0)) 
  (start_of (layout_of aprog) as + 2 * n + 11, [], Oc # xs) ires = False"
apply(simp add: inv_check_left_moving.simps inv_check_left_moving_in_middle.simps)
done

lemma dec_inv_stop2_pre: 
  "\<lbrakk>abc_fetch as aprog = Some (Dec n e); abc_lm_v am n > 0\<rbrakk> \<Longrightarrow> 
    \<forall>na. \<not> (\<lambda>(s, l, r) (ss, n', ires'). 
                     s = start_of (layout_of aprog) as + 2 * n + 16)
   (t_steps (Suc (start_of (layout_of aprog) as), l, r) 
      (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e),
            start_of (layout_of aprog) as - Suc 0) na)
    (start_of (layout_of aprog) as, n, ires) \<and>
 dec_inv_2 (layout_of aprog) n e (as, am)
     (t_steps (Suc (start_of (layout_of aprog) as), l, r) 
      (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e),
          start_of (layout_of aprog) as - Suc 0) na) ires
 \<longrightarrow>
 dec_inv_2 (layout_of aprog) n e (as, am)
     (t_steps (Suc (start_of (layout_of aprog) as), l, r) 
      (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e),
              start_of (layout_of aprog) as - Suc 0) (Suc na)) ires \<and>
 ((t_steps (Suc (start_of (layout_of aprog) as), l, r) 
      (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e),
            start_of (layout_of aprog) as - Suc 0) (Suc na),  
              start_of (layout_of aprog) as, n, ires),
  t_steps (Suc (start_of (layout_of aprog) as), l, r) 
      (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e),
             start_of (layout_of aprog) as - Suc 0) na,
                          start_of (layout_of aprog) as, n, ires)
   \<in> abc_dec_2_LE"
apply(subgoal_tac "start_of (layout_of aprog) as > 0")
apply(rule allI, rule impI, simp add: t_steps_ind)
apply(case_tac "(t_steps (Suc (start_of (layout_of aprog) as), l, r)
     (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), 
             start_of (layout_of aprog) as - Suc 0) na)", simp)
apply(auto split:if_splits simp add:t_step.simps dec_inv_2.simps, 
           tactic {* ALLGOALS (resolve_tac [@{thm fetch_intro}]) *})
apply(simp_all add:dec_fetch_simps new_tape.simps dec_inv_2.simps)
apply(auto simp add: abc_dec_2_LE_def lex_square_def lex_triple_def 
                     lex_pair_def split: if_splits)
apply(auto intro: dec_false_2_b dec_false_2)
apply(rule startof_not0)
done

lemma dec_stop2: 
 "\<lbrakk>ly = layout_of aprog; 
   dec_inv_2 ly n e (as, am) (start_of ly as + 1, l, r) ires; 
   abc_fetch as aprog = Some (Dec n e); 
   abc_lm_v am n > 0\<rbrakk> \<Longrightarrow> 
  (\<exists> stp. (\<lambda> (s', l', r'). s' = start_of ly (Suc as) \<and> 
   dec_inv_2 ly n e (as, am) (s', l', r') ires)
       (t_steps (start_of ly as+1, l, r) (ci ly (start_of ly as)
                           (Dec n e), start_of ly as - Suc 0) stp))"
apply(insert halt_lemma2[of abc_dec_2_LE 
      "\<lambda> ((s, l, r), ss, n', ires'). s = start_of ly (Suc as)"
      "(\<lambda> stp. (t_steps (start_of ly as + 1, l, r) 
       (ci ly (start_of ly as) (Dec n e), start_of ly as - Suc 0) stp,
                 start_of ly as, n, ires))"
      "(\<lambda> ((s, l, r), ss, n, ires'). dec_inv_2 ly n e (as, am) (s, l, r) ires')"])
apply(insert wf_dec_2_le, simp)
apply(insert dec_inv_stop2_pre[of as aprog n e am l r], 
      simp add: t_steps.simps)
apply(erule_tac exE)
apply(rule_tac x = na in exI)
apply(case_tac "(t_steps (Suc (start_of (layout_of aprog) as), l, r) 
(ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), 
            start_of (layout_of aprog) as - Suc 0) na)",
      case_tac b, auto)
done

lemma dec_inv_stop_cond1: 
  "\<lbrakk>ly = layout_of aprog; 
    dec_inv_1 ly n e (as, lm) (s, (l, r)) ires; s = start_of ly e;
    abc_fetch as aprog = Some (Dec n e); abc_lm_v lm n = 0\<rbrakk> 
   \<Longrightarrow> crsp_l ly (e, abc_lm_s lm n 0) (s, l, r) ires"
apply(simp add: dec_inv_1.simps split: if_splits)
apply(auto simp: crsp_l.simps inv_stop.simps )
done

lemma dec_inv_stop_cond2: 
   "\<lbrakk>ly = layout_of aprog; s = start_of ly (Suc as); 
     dec_inv_2 ly n e (as, lm) (s, (l, r)) ires;
     abc_fetch as aprog = Some (Dec n e); 
     abc_lm_v lm n > 0\<rbrakk>
   \<Longrightarrow> crsp_l ly (Suc as,
                  abc_lm_s lm n (abc_lm_v lm n - Suc 0)) (s, l, r) ires"
apply(simp add: dec_inv_2.simps split: if_splits)
apply(auto simp: crsp_l.simps inv_stop.simps )
done

lemma [simp]: "(case Bk\<^bsup>rn\<^esup> of [] \<Rightarrow> Bk |
                 Bk # xs \<Rightarrow> Bk | Oc # xs \<Rightarrow> Oc) = Bk"
apply(case_tac rn, auto)
done

lemma [simp]: "t_steps tc (p,off) (m + n) = 
                   t_steps (t_steps tc (p, off) m) (p, off) n"
apply(induct m arbitrary: n)
apply(simp add: t_steps.simps)
proof -
  fix m n
  assume h1: "\<And>n. t_steps tc (p, off) (m + n) =
                     t_steps (t_steps tc (p, off) m) (p, off) n"
  hence h2: "t_steps tc (p, off) (Suc m + n) = 
                     t_steps tc (p, off) (m + Suc n)"
    by simp
  from h1 and this show 
    "t_steps tc (p, off) (Suc m + n) = 
         t_steps (t_steps tc (p, off) (Suc m)) (p, off) n"
  proof(simp only: h2, simp add: t_steps.simps)
    have h3: "(t_step (t_steps tc (p, off) m) (p, off)) = 
                      (t_steps (t_step tc (p, off)) (p, off) m)"
      apply(simp add: t_steps.simps[THEN sym] t_steps_ind[THEN sym])
      done
    from h3 show 
      "t_steps (t_step (t_steps tc (p, off) m) (p, off)) (p, off) n =          t_steps (t_steps (t_step tc (p, off)) (p, off) m) (p, off) n"
      by simp
  qed
qed

lemma [simp]: " abc_fetch as aprog = Some (Dec n e) \<Longrightarrow> 
          Suc (start_of (layout_of aprog) as) \<noteq> 
                           start_of (layout_of aprog) e"
apply(case_tac "e = as", simp)
apply(case_tac "e < as")
apply(drule_tac a = e and b = as and ly = "layout_of aprog" 
                                           in start_of_le, simp)
apply(drule_tac start_of_ge, auto)
done

lemma [simp]: "inv_locate_b (as, []) (0, Oc # Bk # Bk # ires, Bk\<^bsup>rn - Suc 0\<^esup>) ires"
apply(auto simp: inv_locate_b.simps in_middle.simps)
apply(rule_tac x = "[]" in exI, rule_tac x = "Suc 0" in exI, 
      rule_tac x = 0 in exI, simp)
apply(rule_tac x = "Suc 0" in exI, rule_tac x = 0 in exI, auto)
apply(case_tac rn, simp, case_tac nat, auto)
done

lemma [simp]: 
       "inv_locate_n_b (as, []) (0, Oc # Bk # Bk # ires, Bk\<^bsup>rn - Suc 0\<^esup>) ires"
apply(auto simp: inv_locate_n_b.simps in_middle.simps)
apply(case_tac rn, simp, case_tac nat, auto)
done 

lemma [simp]:
"abc_fetch as aprog = Some (Dec n e) \<Longrightarrow>
   dec_inv_1 (layout_of aprog) n e (as, []) 
    (Suc (start_of (layout_of aprog) as), Oc # Bk # Bk # ires, Bk\<^bsup>rn - Suc 0\<^esup>) ires
\<and>
   dec_inv_2 (layout_of aprog) n e (as, []) 
    (Suc (start_of (layout_of aprog) as), Oc # Bk # Bk # ires, Bk\<^bsup>rn - Suc 0\<^esup>) ires"
apply(simp add: dec_inv_1.simps dec_inv_2.simps)
apply(case_tac n, auto)
done

lemma [simp]: 
 "\<lbrakk>am \<noteq> []; <am> = Oc # r'; 
   abc_fetch as aprog = Some (Dec n e)\<rbrakk> 
 \<Longrightarrow> inv_locate_b (as, am) (0, Oc # Bk # Bk # ires, r' @ Bk\<^bsup>rn\<^esup>) ires"
apply(auto simp: inv_locate_b.simps in_middle.simps)
apply(rule_tac x = "tl am" in exI, rule_tac x = 0 in exI,
      rule_tac x = "hd am" in exI, simp)
apply(rule_tac x = "Suc 0" in exI)
apply(rule_tac x = "hd am" in exI, simp)
apply(case_tac am, simp, case_tac list, auto simp: tape_of_nl_abv tape_of_nat_list.simps)
apply(case_tac rn, auto)
done

lemma [simp]: 
  "\<lbrakk><am> = Oc # r'; abc_fetch as aprog = Some (Dec n e)\<rbrakk> \<Longrightarrow> 
  inv_locate_n_b (as, am) (0, Oc # Bk # Bk # ires, r' @ Bk\<^bsup>rn\<^esup>) ires"
apply(auto simp: inv_locate_n_b.simps)
apply(rule_tac x = "tl am" in exI, rule_tac x = "hd am" in exI, auto)
apply(case_tac [!] am, auto simp: tape_of_nl_abv tape_of_nat_list.simps )
apply(case_tac [!]list, auto simp: tape_of_nl_abv tape_of_nat_list.simps)
apply(case_tac rn, simp, simp)
apply(erule_tac x = nat in allE, simp)
done

lemma [simp]:
   "\<lbrakk>am \<noteq> [];  
     <am> = Oc # r'; 
     abc_fetch as aprog = Some (Dec n e)\<rbrakk> \<Longrightarrow>
    dec_inv_1 (layout_of aprog) n e (as, am) 
      (Suc (start_of (layout_of aprog) as), 
           Oc # Bk # Bk # ires, r' @ Bk\<^bsup>rn\<^esup>) ires \<and>
    dec_inv_2 (layout_of aprog) n e (as, am) 
      (Suc (start_of (layout_of aprog) as), 
           Oc # Bk # Bk # ires, r' @ Bk\<^bsup>rn\<^esup>) ires"
apply(simp add: dec_inv_1.simps dec_inv_2.simps)
apply(case_tac n, auto)
done

lemma [simp]: "am \<noteq> [] \<Longrightarrow>  \<exists>r'. <am::nat list> = Oc # r'"
apply(case_tac am, simp, case_tac list)
apply(auto simp: tape_of_nl_abv tape_of_nat_list.simps )
done

lemma [simp]: "start_of (layout_of aprog) as > 0 \<Longrightarrow> 
      (fetch (ci (layout_of aprog) 
           (start_of (layout_of aprog) as) (Dec n e)) (Suc 0)  Bk)
    = (W1, start_of (layout_of aprog) as)"
apply(auto simp: ci.simps findnth.simps fetch.simps
             nth_of.simps tshift.simps nth_append Suc_pre tdec_b_def)
thm findnth_nth
apply(insert findnth_nth[of 0 n 0], simp)
apply(simp add: findnth.simps)
done

lemma [simp]:
    "start_of (layout_of aprog) as > 0
   \<Longrightarrow> (t_step (start_of (layout_of aprog) as, Bk # Bk # ires, Bk\<^bsup>rn\<^esup>)
    (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), 
                             start_of (layout_of aprog) as - Suc 0))
   = (start_of (layout_of aprog) as, Bk # Bk # ires, Oc # Bk\<^bsup>rn- Suc 0\<^esup>)"
apply(simp add: t_step.simps)
apply(case_tac "start_of (layout_of aprog) as",
      auto simp: new_tape.simps)
apply(case_tac rn, auto)
done

lemma [simp]: "start_of (layout_of aprog) as > 0 \<Longrightarrow> 
 (fetch (ci (layout_of aprog) (start_of (layout_of aprog) as) 
         (Dec n e)) (Suc 0)  Oc)
  = (R, Suc (start_of (layout_of aprog) as))"

apply(auto simp: ci.simps findnth.simps fetch.simps
                 nth_of.simps tshift.simps nth_append 
                 Suc_pre tdec_b_def)
apply(insert findnth_nth[of 0 n "Suc 0"], simp)
apply(simp add: findnth.simps)
done

lemma [simp]: "start_of (layout_of aprog) as > 0 \<Longrightarrow> 
 (t_step (start_of (layout_of aprog) as, Bk # Bk # ires, Oc # Bk\<^bsup>rn - Suc 0\<^esup>)
     (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e), 
        start_of (layout_of aprog) as - Suc 0)) =
  (Suc (start_of (layout_of aprog) as), Oc # Bk # Bk # ires, Bk\<^bsup>rn-Suc 0\<^esup>)"
apply(simp add: t_step.simps)
apply(case_tac "start_of (layout_of aprog) as", 
      auto simp: new_tape.simps)
done

lemma [simp]: "start_of (layout_of aprog) as > 0 \<Longrightarrow> 
 t_step (start_of (layout_of aprog) as, Bk # Bk # ires, Oc # r' @ Bk\<^bsup>rn\<^esup>) 
      (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e),
                 start_of (layout_of aprog) as - Suc 0) =
      (Suc (start_of (layout_of aprog) as), Oc # Bk # Bk # ires, r' @ Bk\<^bsup>rn\<^esup>)"
apply(simp add: t_step.simps)
apply(case_tac "start_of (layout_of aprog) as", 
      auto simp: new_tape.simps)
done

lemma crsp_next_state:
  "\<lbrakk>crsp_l (layout_of aprog) (as, am) tc ires; 
    abc_fetch as aprog = Some (Dec n e)\<rbrakk>
  \<Longrightarrow> \<exists> stp' > 0. (\<lambda> (s, l, r). 
           (s = Suc (start_of (layout_of aprog) as) 
 \<and> (dec_inv_1 (layout_of aprog) n e (as, am) (s, l, r) ires) 
 \<and> (dec_inv_2 (layout_of aprog) n e (as, am) (s, l, r)) ires)) 
     (t_steps tc (ci (layout_of aprog) (start_of (layout_of aprog) as)
             (Dec n e), start_of (layout_of aprog) as - Suc 0) stp')"
apply(subgoal_tac "start_of (layout_of aprog) as > 0")
apply(case_tac tc, case_tac b, auto simp: crsp_l.simps)
apply(case_tac "am = []", simp)
apply(rule_tac x = "Suc (Suc 0)" in exI, simp add: t_steps.simps)
proof-
  fix  rn
  assume h1: "am \<noteq> []" "abc_fetch as aprog = Some (Dec n e)" 
             "start_of (layout_of aprog) as > 0"
  hence h2: "\<exists> r'. <am> = Oc # r'"
    by simp
  from h1 and h2 show 
   "\<exists>stp'>0. case t_steps (start_of (layout_of aprog) as, Bk # Bk # ires, <am> @ Bk\<^bsup>rn\<^esup>)
    (ci (layout_of aprog) (start_of (layout_of aprog) as) (Dec n e),
    start_of (layout_of aprog) as - Suc 0) stp' of
    (s, ab) \<Rightarrow> s = Suc (start_of (layout_of aprog) as) \<and>
    dec_inv_1 (layout_of aprog) n e (as, am) (s, ab) ires \<and> 
    dec_inv_2 (layout_of aprog) n e (as, am) (s, ab) ires"
  proof(erule_tac exE, simp, rule_tac x = "Suc 0" in exI, 
        simp add: t_steps.simps)
  qed
next
  assume "abc_fetch as aprog = Some (Dec n e)"
  thus "0 < start_of (layout_of aprog) as"
   apply(insert startof_not0[of "layout_of aprog" as], simp)
   done
qed

lemma dec_crsp_ex1: 
  "\<lbrakk>crsp_l (layout_of aprog) (as, am) tc ires;
  abc_fetch as aprog = Some (Dec n e); 
  abc_lm_v am n = 0\<rbrakk>
  \<Longrightarrow> \<exists>stp > 0. crsp_l (layout_of aprog) (e, abc_lm_s am n 0) 
    (t_steps tc (ci (layout_of aprog) (start_of (layout_of aprog) as)
 (Dec n e), start_of (layout_of aprog) as - Suc 0) stp) ires"
proof -
  assume h1: "crsp_l (layout_of aprog) (as, am) tc ires" 
       "abc_fetch as aprog = Some (Dec n e)" "abc_lm_v am n = 0"
  hence h2: "\<exists> stp' > 0. (\<lambda> (s, l, r). 
    (s = Suc (start_of (layout_of aprog) as) \<and> 
 (dec_inv_1 (layout_of aprog) n e (as, am) (s, l, r)) ires)) 
   (t_steps tc (ci (layout_of aprog) (start_of (layout_of aprog) as) 
      (Dec n e), start_of (layout_of aprog) as - Suc 0) stp')"
    apply(insert crsp_next_state[of aprog as am tc ires n e], auto)
    done
  from h1 and h2 show 
 "\<exists>stp > 0. crsp_l (layout_of aprog) (e, abc_lm_s am n 0) 
           (t_steps tc (ci (layout_of aprog) (start_of 
                (layout_of aprog) as) (Dec n e), 
                    start_of (layout_of aprog) as - Suc 0) stp) ires" 
  proof(erule_tac exE, case_tac "(t_steps tc (ci (layout_of aprog)
       (start_of (layout_of aprog) as) (Dec n e), start_of 
          (layout_of aprog) as - Suc 0) stp')",  simp)
    fix stp' a b c
    assume h3: "stp' > 0 \<and> a = Suc (start_of (layout_of aprog) as) \<and> 
               dec_inv_1 (layout_of aprog) n e (as, am) (a, b, c) ires" 
             "abc_fetch as aprog = Some (Dec n e)" "abc_lm_v am n = 0"
     "t_steps tc (ci (layout_of aprog) (start_of (layout_of aprog) as)
          (Dec n e), start_of (layout_of aprog) as - Suc 0) stp' 
        = (Suc (start_of (layout_of aprog) as), b, c)" 
    thus "\<exists>stp > 0. crsp_l (layout_of aprog) (e, abc_lm_s am n 0) 
     (t_steps tc (ci (layout_of aprog) (start_of (layout_of aprog) as)
           (Dec n e), start_of (layout_of aprog) as - Suc 0) stp) ires"
    proof(erule_tac conjE, simp)
      assume "dec_inv_1 (layout_of aprog) n e (as, am) 
                    (Suc (start_of (layout_of aprog) as), b, c) ires"     
             "abc_fetch as aprog = Some (Dec n e)" 
             "abc_lm_v am n = 0"
             " t_steps tc (ci (layout_of aprog) 
              (start_of (layout_of aprog) as) (Dec n e), 
               start_of (layout_of aprog) as - Suc 0) stp' 
             = (Suc (start_of (layout_of aprog) as), b, c)"
      hence h4: "\<exists>stp. (\<lambda>(s', l', r'). s' = 
                     start_of (layout_of aprog) e \<and> 
                dec_inv_1 (layout_of aprog) n e (as, am) (s', l', r') ires)
                 (t_steps (start_of (layout_of aprog) as + 1, b, c) 
                  (ci (layout_of aprog) 
                      (start_of (layout_of aprog) as) (Dec n e), 
                         start_of (layout_of aprog) as - Suc 0) stp)"
	apply(rule_tac dec_inv_stop1, auto)
	done
      from  h3 and h4 show ?thesis
	apply(erule_tac exE)
	apply(rule_tac x = "stp' + stp" in exI, simp)
	apply(case_tac "(t_steps (Suc (start_of (layout_of aprog) as),
                     b, c) (ci (layout_of aprog) 
                     (start_of (layout_of aprog) as) (Dec n e), 
                      start_of (layout_of aprog) as - Suc 0) stp)", 
              simp)
	apply(rule_tac dec_inv_stop_cond1, auto)
	done
    qed
  qed
qed
	  
lemma dec_crsp_ex2:
  "\<lbrakk>crsp_l (layout_of aprog) (as, am) tc ires; 
    abc_fetch as aprog = Some (Dec n e);
    0 < abc_lm_v am n\<rbrakk>
 \<Longrightarrow> \<exists>stp > 0. crsp_l (layout_of aprog) 
               (Suc as, abc_lm_s am n (abc_lm_v am n - Suc 0))
   (t_steps tc (ci (layout_of aprog) (start_of (layout_of aprog) as) 
              (Dec n e), start_of (layout_of aprog) as - Suc 0) stp) ires"
proof -
  assume h1: 
 "crsp_l (layout_of aprog) (as, am) tc ires" 
 "abc_fetch as aprog = Some (Dec n e)"
  "abc_lm_v am n > 0"
  hence h2: 
 "\<exists> stp' > 0. (\<lambda> (s, l, r). (s = Suc (start_of (layout_of aprog) as)
 \<and> (dec_inv_2 (layout_of aprog) n e (as, am) (s, l, r)) ires)) 
(t_steps tc (ci (layout_of aprog) (start_of (layout_of aprog) as) 
              (Dec n e), start_of (layout_of aprog) as - Suc 0) stp')"
    apply(insert crsp_next_state[of aprog as am tc ires n e], auto)
    done
  from h1 and h2 show 
 "\<exists>stp >0. crsp_l (layout_of aprog) 
   (Suc as, abc_lm_s am n (abc_lm_v am n - Suc 0))
   (t_steps tc (ci (layout_of aprog) (start_of (layout_of aprog) as) 
               (Dec n e), start_of (layout_of aprog) as - Suc 0) stp) ires"
  proof(erule_tac exE, 
        case_tac 
 "(t_steps tc (ci (layout_of aprog) (start_of (layout_of aprog) as) 
      (Dec n e), start_of (layout_of aprog) as - Suc 0) stp')",  simp)
    fix stp' a b c
    assume h3: "0 < stp' \<and> a = Suc (start_of (layout_of aprog) as) \<and>
               dec_inv_2 (layout_of aprog) n e (as, am) (a, b, c) ires" 
               "abc_fetch as aprog = Some (Dec n e)" 
               "abc_lm_v am n > 0"
               "t_steps tc (ci (layout_of aprog) 
                   (start_of (layout_of aprog) as) (Dec n e), 
                     start_of (layout_of aprog) as - Suc 0) stp' 
                  = (Suc (start_of (layout_of aprog) as), b, c)"
    thus "?thesis"
    proof(erule_tac conjE, simp)
      assume 
    "dec_inv_2 (layout_of aprog) n e (as, am) 
      (Suc (start_of (layout_of aprog) as), b, c) ires" 
    "abc_fetch as aprog = Some (Dec n e)" "abc_lm_v am n > 0"
    "t_steps tc (ci (layout_of aprog) (start_of (layout_of aprog) as)
         (Dec n e), start_of (layout_of aprog) as - Suc 0) stp'
             = (Suc (start_of (layout_of aprog) as), b, c)"
      hence h4: 
   "\<exists>stp. (\<lambda>(s', l', r'). s' = start_of (layout_of aprog) (Suc as) \<and>
           dec_inv_2 (layout_of aprog) n e (as, am) (s', l', r') ires)
             (t_steps (start_of (layout_of aprog) as + 1, b, c) 
              (ci (layout_of aprog) (start_of (layout_of aprog) as) 
               (Dec n e), start_of (layout_of aprog) as - Suc 0) stp)"
	apply(rule_tac dec_stop2, auto)
	done
      from  h3 and h4 show ?thesis
	apply(erule_tac exE)
	apply(rule_tac x = "stp' + stp" in exI, simp)
	apply(case_tac 
         "(t_steps (Suc (start_of (layout_of aprog) as), b, c) 
           (ci (layout_of aprog) (start_of (layout_of aprog) as)
             (Dec n e), start_of (layout_of aprog) as - Suc 0) stp)"
              ,simp)
	apply(rule_tac dec_inv_stop_cond2, auto)
	done
    qed
  qed
qed

lemma dec_crsp_ex_pre:
  "\<lbrakk>ly = layout_of aprog; crsp_l ly (as, am) tc ires; 
     abc_fetch as aprog = Some (Dec n e)\<rbrakk>
 \<Longrightarrow> \<exists>stp > 0. crsp_l ly (abc_step_l (as, am) (Some (Dec n e))) 
      (t_steps tc (ci (layout_of aprog) (start_of ly as) (Dec n e),
                                       start_of ly as - Suc 0) stp) ires"
apply(auto simp: abc_step_l.simps intro: dec_crsp_ex2 dec_crsp_ex1)
done

lemma dec_crsp_ex:
  assumes layout: -- {* There is an Abacus program @{text "aprog"} with layout @{text "ly"} *}
  "ly = layout_of aprog"
  and dec: -- {* There is an @{text "Dec n e"} instruction at postion @{text "as"} of @{text "aprog"} *}
      "abc_fetch as aprog = Some (Dec n e)"
  and correspond: 
  -- {* Abacus configuration @{text "(as, am)"} is in correspondence with TM 
         configuration @{text "tc"}
      *}
  "crsp_l ly (as, am) tc ires"
shows 
   "\<exists>stp > 0. crsp_l ly (abc_step_l (as, am) (Some (Dec n e))) 
      (t_steps tc (ci (layout_of aprog) (start_of ly as) (Dec n e),
                                       start_of ly as - Suc 0) stp) ires"
proof -
  from dec_crsp_ex_pre layout dec correspond  show ?thesis by blast
qed

(*
subsection {* Compilation of @{text "Goto n"}*}
*)

lemma goto_fetch: 
     "fetch (ci (layout_of aprog) 
         (start_of (layout_of aprog) as) (Goto n)) (Suc 0)  b
     = (Nop, start_of (layout_of aprog) n)"
apply(auto simp: ci.simps fetch.simps nth_of.simps 
           split: block.splits)
done

text {*
  Correctness of complied @{text "Goto n"}
  *}

lemma goto_crsp_ex_pre: 
  "\<lbrakk>ly = layout_of aprog; 
    crsp_l ly (as, am) tc ires;
    abc_fetch as aprog = Some (Goto n)\<rbrakk>
 \<Longrightarrow> \<exists>stp > 0. crsp_l ly (abc_step_l (as, am) (Some (Goto n))) 
      (t_steps tc (ci (layout_of aprog) (start_of ly as) (Goto n), 
                                        start_of ly as - Suc 0) stp) ires"
apply(rule_tac x = 1 in exI)
apply(simp add: abc_step_l.simps t_steps.simps t_step.simps)
apply(case_tac tc, simp)
apply(subgoal_tac "a = start_of (layout_of aprog) as", auto)
apply(subgoal_tac "start_of (layout_of aprog) as > 0", simp)
apply(auto simp: goto_fetch new_tape.simps crsp_l.simps)
apply(rule startof_not0)
done

lemma goto_crsp_ex:
  assumes layout: "ly = layout_of aprog"
  and goto: "abc_fetch as aprog = Some (Goto n)"
  and correspondence: "crsp_l ly (as, am) tc ires"
  shows "\<exists>stp>0. crsp_l ly (abc_step_l (as, am) (Some (Goto n))) 
              (t_steps tc (ci (layout_of aprog) (start_of ly as) (Goto n),
                                           start_of ly as - Suc 0) stp) ires"
proof -
  from goto_crsp_ex_pre and layout goto correspondence show "?thesis" by blast
qed

subsection {*
  The correctness of the compiler
  *}

declare abc_step_l.simps[simp del]

lemma tm_crsp_ex: 
         "\<lbrakk>ly = layout_of aprog;
           crsp_l ly (as, am) tc ires; 
           as < length aprog;
           abc_fetch as aprog = Some ins\<rbrakk>
      \<Longrightarrow> \<exists> n > 0. crsp_l ly (abc_step_l (as,am) (Some ins))
               (t_steps tc (ci (layout_of aprog) (start_of ly as) 
                  (ins), (start_of ly as) - (Suc 0)) n) ires"
apply(case_tac "ins", simp)
apply(auto intro: inc_crsp_ex_pre dec_crsp_ex goto_crsp_ex)
done

lemma start_of_pre: 
  "n < length aprog \<Longrightarrow> start_of (layout_of aprog) n
                     = start_of (layout_of (butlast aprog)) n"
apply(induct n, simp add: start_of.simps, simp)
apply(simp add: layout_of.simps start_of.simps)
apply(subgoal_tac "n < length aprog - Suc 0", simp)
apply(subgoal_tac "(aprog ! n) = (butlast aprog ! n)", simp)
proof -
  fix n
  assume h1: "Suc n < length aprog"
  thus "aprog ! n = butlast aprog ! n"
    apply(case_tac "length aprog", simp, simp)
    apply(insert nth_append[of "butlast aprog" "[last aprog]" n])
    apply(subgoal_tac "(butlast aprog @ [last aprog]) = aprog")
    apply(simp split: if_splits)
    apply(rule append_butlast_last_id, case_tac aprog, simp, simp)
    done
next
  fix n
  assume "Suc n < length aprog"
  thus "n < length aprog - Suc 0"
    apply(case_tac aprog, simp, simp)
    done
qed
    
lemma zip_eq: "xs = ys \<Longrightarrow> zip xs zs = zip ys zs"
by simp

lemma tpairs_of_append_iff: "length aprog = Suc n \<Longrightarrow> 
         tpairs_of aprog = tpairs_of (butlast aprog) @ 
                     [(start_of (layout_of aprog) n, aprog ! n)]"
apply(simp add: tpairs_of.simps)
apply(insert zip_append[of "map (start_of (layout_of aprog)) [0..<n]"
     "butlast aprog" "[start_of (layout_of aprog) n]" "[last aprog]"])
apply(simp del: zip_append)
apply(subgoal_tac "(butlast aprog @ [last aprog]) = aprog", auto)
apply(rule_tac zip_eq, auto)
apply(rule_tac start_of_pre, simp)
apply(insert last_conv_nth[of aprog], case_tac aprog, simp, simp)
apply(rule append_butlast_last_id, case_tac aprog, simp, simp)
done

lemma [simp]: "list_all (\<lambda>(n, tm). abacus.t_ncorrect (ci layout n tm))
         (zip (map (start_of layout) [0..<length aprog]) aprog)"
proof(induct "length aprog" arbitrary: aprog, simp)
  fix x aprog
  assume ind: "\<And>aprog. x = length aprog \<Longrightarrow> 
        list_all (\<lambda>(n, tm). abacus.t_ncorrect (ci layout n tm))
           (zip (map (start_of layout) [0..<length aprog]) aprog)"
  and h: "Suc x = length (aprog::abc_inst list)"
  have g1: "list_all (\<lambda>(n, tm). abacus.t_ncorrect (ci layout n tm)) 
    (zip (map (start_of layout) [0..<length (butlast aprog)]) 
                                                 (butlast aprog))"
    using h
    apply(rule_tac ind, auto)
    done
  have g2: "(map (start_of layout) [0..<length aprog]) = 
                     map (start_of layout) ([0..<length aprog - 1] 
         @ [length aprog - 1])"
    using h
    apply(case_tac aprog, simp, simp)
    done
  have "\<exists> xs a. aprog = xs @ [a]"
    using h
    apply(rule_tac x = "butlast aprog" in exI, 
          rule_tac x = "last aprog" in exI)
    apply(case_tac "aprog = []", simp, simp)
    done
  from this obtain xs where "\<exists> a. aprog = xs @ [a]" ..
  from this obtain a where g3: "aprog = xs @ [a]" ..
  from g1 and g2 and g3 show "list_all (\<lambda>(n, tm). 
                              abacus.t_ncorrect (ci layout n tm)) 
              (zip (map (start_of layout) [0..<length aprog]) aprog)"
    apply(simp)
    apply(auto simp: t_ncorrect.simps ci.simps  tshift.simps 
          tinc_b_def tdec_b_def split: abc_inst.splits)
    apply arith+
    done
qed

lemma [intro]: "abc2t_correct aprog"
apply(simp add: abc2t_correct.simps tpairs_of.simps 
          split: abc_inst.splits)
done

lemma as_out: "\<lbrakk>ly = layout_of aprog; tprog = tm_of aprog; 
                crsp_l ly (as, am) tc ires; length aprog \<le> as\<rbrakk> 
            \<Longrightarrow> abc_step_l (as, am) (abc_fetch as aprog) = (as, am)"
apply(simp add: abc_fetch.simps abc_step_l.simps)
done

lemma tm_merge_ex: 
  "\<lbrakk>crsp_l (layout_of aprog) (as, am) tc ires; 
    as < length aprog; 
    abc_fetch as aprog = Some a; 
    abc2t_correct aprog;
    crsp_l (layout_of aprog) (abc_step_l (as, am) (Some a))
     (t_steps tc (ci (layout_of aprog) (start_of (layout_of aprog) as)
         a, start_of (layout_of aprog) as - Suc 0) n) ires; 
    n > 0\<rbrakk>
   \<Longrightarrow> \<exists>stp > 0. crsp_l (layout_of aprog) (abc_step_l (as, am) 
                       (Some a)) (t_steps tc (tm_of aprog, 0) stp) ires"
apply(case_tac "(t_steps tc (ci (layout_of aprog) 
           (start_of (layout_of aprog) as) a, 
            start_of (layout_of aprog) as - Suc 0) n)",  simp)
apply(case_tac "(abc_step_l (as, am) (Some a))", simp)
proof -
  fix aa b c aaa ba 
  assume h: 
  "crsp_l (layout_of aprog) (as, am) tc ires" 
  "as < length aprog" 
  "abc_fetch as aprog = Some a" 
  "crsp_l (layout_of aprog) (aaa, ba) (aa, b, c) ires" 
  "abc2t_correct aprog" 
  "n>0"
  "t_steps tc (ci (layout_of aprog) (start_of (layout_of aprog) as) a,
      start_of (layout_of aprog) as - Suc 0) n = (aa, b, c)" 
   "abc_step_l (as, am) (Some a) = (aaa, ba)"
  hence "aa = start_of (layout_of aprog) aaa"
    apply(simp add: crsp_l.simps)
    done
  from this and h show 
  "\<exists>stp > 0. crsp_l (layout_of aprog) (aaa, ba) 
                          (t_steps tc (tm_of aprog, 0) stp) ires"
    apply(insert tms_out_ex[of "layout_of aprog" aprog 
                "tm_of aprog" as am tc ires a n aa b c aaa ba], auto)
    done
qed
 
lemma crsp_inside: 
  "\<lbrakk>ly = layout_of aprog; 
    tprog = tm_of aprog;
    crsp_l ly (as, am) tc ires;
    as < length aprog\<rbrakk> \<Longrightarrow> 
    (\<exists> stp > 0. crsp_l ly (abc_step_l (as,am) (abc_fetch as aprog)) 
                                         (t_steps tc (tprog, 0) stp) ires)"
apply(case_tac "abc_fetch as aprog", simp add: abc_fetch.simps)
proof -
  fix a
  assume "ly = layout_of aprog" 
     "tprog = tm_of aprog" 
     "crsp_l ly (as, am) tc ires" 
     "as < length aprog" 
     "abc_fetch as aprog = Some a"
  thus "\<exists>stp > 0. crsp_l ly (abc_step_l (as, am) 
                 (abc_fetch as aprog)) (t_steps tc (tprog, 0) stp) ires"
    proof(insert tm_crsp_ex[of ly aprog as am tc ires a], 
          auto intro: tm_merge_ex)
  qed
qed

lemma crsp_outside: 
  "\<lbrakk>ly = layout_of aprog; tprog = tm_of aprog;
    crsp_l ly (as, am) tc ires; as \<ge> length aprog\<rbrakk>
    \<Longrightarrow> (\<exists> stp. crsp_l ly (abc_step_l (as,am) (abc_fetch as aprog)) 
                                         (t_steps tc (tprog, 0) stp) ires)"
apply(subgoal_tac "abc_step_l (as, am) (abc_fetch as aprog)
                = (as, am)", simp)
apply(rule_tac x = 0 in exI, simp add: t_steps.simps)
apply(rule as_out, simp+)
done

text {*
  Single-step correntess of the compiler.
*}
lemma astep_crsp_pre: 
      "\<lbrakk>ly = layout_of aprog; 
        tprog = tm_of aprog;
        crsp_l ly (as, am) tc ires\<rbrakk>
       \<Longrightarrow> (\<exists> stp. crsp_l ly (abc_step_l (as,am) 
                  (abc_fetch as aprog)) (t_steps tc (tprog, 0) stp) ires)"
apply(case_tac "as < length aprog")
apply(drule_tac crsp_inside, auto)
apply(rule_tac crsp_outside, simp+)
done

text {*
  Single-step correntess of the compiler.
*}
lemma astep_crsp_pre1: 
      "\<lbrakk>ly = layout_of aprog;
        tprog = tm_of aprog;
        crsp_l ly (as, am) tc ires\<rbrakk>
       \<Longrightarrow> (\<exists> stp. crsp_l ly (abc_step_l (as,am) 
                  (abc_fetch as aprog)) (t_steps tc (tprog, 0) stp) ires)"
apply(case_tac "as < length aprog")
apply(drule_tac crsp_inside, auto)
apply(rule_tac crsp_outside, simp+)
done

lemma astep_crsp:
  assumes layout: 
  -- {* There is a Abacus program @{text "aprog"} with layout @{text "ly"} *}
  "ly = layout_of aprog"
  and compiled: 
  -- {* @{text "tprog"} is the TM compiled from @{text "aprog"} *}
  "tprog = tm_of aprog"
  and corresponds: 
  -- {* Abacus configuration @{text "(as, am)"} is in correspondence with TM configuration
   @{text "tc"} *}
  "crsp_l ly (as, am) tc ires"
  -- {* One step execution of @{text "aprog"} can be simulated by multi-step execution 
  of @{text "tprog"} *}
  shows "(\<exists> stp. crsp_l ly (abc_step_l (as,am) 
                  (abc_fetch as aprog)) (t_steps tc (tprog, 0) stp) ires)"
proof -
  from astep_crsp_pre1 [OF layout compiled corresponds] show ?thesis .
qed

lemma steps_crsp_pre: 
    "\<lbrakk>ly = layout_of aprog; tprog = tm_of aprog; 
      crsp_l ly ac tc ires; ac' = abc_steps_l ac aprog n\<rbrakk> \<Longrightarrow> 
        (\<exists> n'. crsp_l ly ac' (t_steps tc (tprog, 0) n') ires)"
apply(induct n arbitrary: ac' ac tc, simp add: abc_steps_l.simps)
apply(rule_tac x = 0 in exI)
apply(case_tac ac, simp add: abc_steps_l.simps t_steps.simps)
apply(case_tac ac, simp add: abc_steps_l.simps)
apply(subgoal_tac 
   "(\<exists> stp. crsp_l ly (abc_step_l (a, b)
            (abc_fetch a aprog)) (t_steps tc (tprog, 0) stp) ires)")
apply(erule exE)
apply(subgoal_tac 
   "\<exists>n'. crsp_l (layout_of aprog) 
    (abc_steps_l (abc_step_l (a, b) (abc_fetch a aprog)) aprog n)
         (t_steps ((t_steps tc (tprog, 0) stp)) (tm_of aprog, 0) n') ires")
apply(erule exE)
apply(subgoal_tac 
    "t_steps (t_steps tc (tprog, 0) stp) (tm_of aprog, 0) n' =
     t_steps tc (tprog, 0) (stp + n')")
apply(rule_tac x = "stp + n'" in exI, simp)
apply(auto intro: astep_crsp simp: t_step_add)
done

text {*
  Multi-step correctess of the compiler.
*}

lemma steps_crsp: 
  assumes layout: 
  -- {* There is an Abacus program @{text "aprog"} with layout @{text "ly"} *}
    "ly = layout_of aprog"
  and compiled: 
  -- {* @{text "tprog"} is the TM compiled from @{text "aprog"} *}
  "tprog = tm_of aprog"
  and correspond: 
  -- {* Abacus configuration @{text "ac"} is in correspondence with TM configuration @{text "tc"} *}
      "crsp_l ly ac tc ires"
  and execution: 
  -- {* @{text "ac'"} is the configuration obtained from @{text "n"}-step execution 
      of @{text "aprog"} starting from configuration @{text "ac"} *}
  "ac' = abc_steps_l ac aprog n" 
  -- {* There exists steps @{text "n'"} steps, after these steps of execution, 
  the Turing configuration such obtained is in correspondence with @{text "ac'"} *}
  shows "(\<exists> n'. crsp_l ly ac' (t_steps tc (tprog, 0) n') ires)"
proof -
  from steps_crsp_pre [OF layout compiled correspond execution] show ?thesis .
qed

subsection {* The Mop-up machine *}

fun mop_bef :: "nat \<Rightarrow> tprog"
  where
  "mop_bef 0 = []" |
  "mop_bef (Suc n) = mop_bef n @ 
       [(R, 2*n + 3), (W0, 2*n + 2), (R, 2*n + 1), (W1, 2*n + 2)]"

definition mp_up :: "tprog"
  where
  "mp_up \<equiv> [(R, 2), (R, 1), (L, 5), (W0, 3), (R, 4), (W0, 3),
            (R, 2), (W0, 3), (L, 5), (L, 6), (R, 0), (L, 6)]"

fun tMp :: "nat \<Rightarrow> nat \<Rightarrow> tprog"
  where 
  "tMp n off = tshift (mop_bef n @ tshift mp_up (2*n)) off"

declare  mp_up_def[simp del]  tMp.simps[simp del] mop_bef.simps[simp del]
(**********Begin: equiv among aba and turing***********)

lemma tm_append_step: 
 "\<lbrakk>t_ncorrect tp1; t_step tc (tp1, 0) = (s, l, r); s \<noteq> 0\<rbrakk> 
 \<Longrightarrow> t_step tc (tp1 @ tp2, 0) = (s, l, r)"
apply(simp add: t_step.simps)
apply(case_tac tc, simp)
apply(case_tac 
       "(fetch tp1 a (case c of [] \<Rightarrow> Bk |
               Bk # xs \<Rightarrow> Bk | Oc # xs \<Rightarrow> Oc))", simp)
apply(case_tac a, simp add: fetch.simps)
apply(simp add: fetch.simps)
apply(case_tac c, simp)
apply(case_tac [!] "ab::block")
apply(auto simp: nth_of.simps nth_append t_ncorrect.simps 
           split: if_splits)
done

lemma state0_ind: "t_steps (0, l, r) (tp, 0) stp = (0, l, r)"
apply(induct stp, simp add: t_steps.simps)
apply(simp add: t_steps.simps t_step.simps fetch.simps new_tape.simps)
done

lemma tm_append_steps:  
 "\<lbrakk>t_ncorrect tp1; t_steps tc (tp1, 0) stp = (s, l ,r); s \<noteq> 0\<rbrakk>
  \<Longrightarrow> t_steps tc (tp1 @ tp2, 0) stp = (s, l, r)"
apply(induct stp arbitrary: tc s l r)
apply(case_tac tc,  simp)
apply(simp add: t_steps.simps)
proof -
  fix stp tc s l r
  assume h1: "\<And>tc s l r. \<lbrakk>t_ncorrect tp1; t_steps tc (tp1, 0) stp = 
   (s, l, r); s \<noteq> 0\<rbrakk> \<Longrightarrow> t_steps tc (tp1 @ tp2, 0) stp = (s, l, r)"
    and h2: "t_steps tc (tp1, 0) (Suc stp) = (s, l, r)" "s \<noteq> 0" 
            "t_ncorrect tp1"
  thus "t_steps tc (tp1 @ tp2, 0) (Suc stp) = (s, l, r)"
    apply(simp add: t_steps.simps)
    apply(case_tac "(t_step tc (tp1, 0))", simp)
    proof-
      fix a b c 
      assume g1: "\<And>tc s l r. \<lbrakk>t_steps tc (tp1, 0) stp = (s, l, r); 
                0 < s\<rbrakk> \<Longrightarrow> t_steps tc (tp1 @ tp2, 0) stp = (s, l, r)"
	and g2: "t_step tc (tp1, 0) = (a, b, c)" 
                "t_steps (a, b, c) (tp1, 0) stp = (s, l, r)" 
                "0 < s" 
                "t_ncorrect tp1"
      hence g3: "a > 0"
	apply(case_tac "a::nat", auto simp: t_steps.simps)
	apply(simp add: state0_ind)
	done
      from g1 and g2 and this have g4: 
                    "(t_step tc (tp1 @ tp2, 0)) = (a, b, c)"
	apply(rule_tac tm_append_step, simp, simp, simp)
	done
      from g1 and g2 and g3 and g4 show 
          "t_steps (t_step tc (tp1 @ tp2, 0)) (tp1 @ tp2, 0) stp
                                                         = (s, l, r)"
	apply(simp)
	done
    qed
qed

lemma shift_fetch: 
 "\<lbrakk>n < length tp; 
  (tp:: (taction \<times> nat) list) ! n = (aa, ba);
   ba \<noteq> 0\<rbrakk> 
   \<Longrightarrow> (tshift tp (length tp div 2)) ! n = 
                     (aa , ba + length tp div 2)"
apply(simp add: tshift.simps)
done

lemma tshift_length_equal: "length (tshift tp q) = length tp"
apply(auto simp: tshift.simps)
done

thm nth_of.simps

lemma [simp]: "t_ncorrect tp \<Longrightarrow> 2 * (length tp div 2) = length tp"
apply(auto simp: t_ncorrect.simps)
done

lemma  tm_append_step_equal': 
   "\<lbrakk>t_ncorrect tp; t_ncorrect tp'; off = length tp div 2\<rbrakk> \<Longrightarrow> 
    (\<lambda> (s, l, r). ((\<lambda> (s', l', r'). 
      (s'\<noteq> 0 \<longrightarrow> (s = s' + off \<and> l = l' \<and> r = r'))) 
         (t_step (a, b, c) (tp', 0))))
               (t_step (a + off, b, c) (tp @ tshift tp' off, 0))"
apply(simp add: t_step.simps)
apply(case_tac a, simp add: fetch.simps)
apply(case_tac 
"(fetch tp' a (case c of [] \<Rightarrow> Bk | Bk # xs \<Rightarrow> Bk | Oc # xs \<Rightarrow> Oc))",
 simp)
apply(case_tac 
"(fetch (tp @ tshift tp' (length tp div 2))
        (Suc (nat + length tp div 2)) 
           (case c of [] \<Rightarrow> Bk | Bk # xs \<Rightarrow> Bk | Oc # xs \<Rightarrow> Oc))", 
 simp)
apply(case_tac "(new_tape aa (b, c))",
      case_tac "(new_tape aaa (b, c))", simp, 
      rule impI, simp add: fetch.simps split: block.splits option.splits)
apply (auto simp: nth_of.simps t_ncorrect.simps 
                      nth_append tshift_length_equal tshift.simps split: if_splits)
done


lemma  tm_append_step_equal: 
 "\<lbrakk>t_ncorrect tp; t_ncorrect tp'; off = length tp div 2; 
   t_step (a, b, c) (tp', 0) = (aa, ab, bb);  aa \<noteq> 0\<rbrakk>
 \<Longrightarrow> t_step (a + length tp div 2, b, c) 
        (tp @ tshift tp' (length tp div 2), 0)
                          = (aa + length tp div 2, ab, bb)"
apply(insert tm_append_step_equal'[of tp tp' off a b c], simp)
apply(case_tac "(t_step (a + length tp div 2, b, c) 
                   (tp @ tshift tp' (length tp div 2), 0))", simp)
done

lemma tm_append_steps_equal: 
 "\<lbrakk>t_ncorrect tp; t_ncorrect tp'; off = length tp div 2\<rbrakk> \<Longrightarrow> 
   (\<lambda> (s, l, r). ((\<lambda> (s', l', r'). ((s'\<noteq> 0 \<longrightarrow> s = s' + off \<and> l = l'
                     \<and> r = r'))) (t_steps (a, b, c) (tp', 0) stp)))
   (t_steps (a + off, b, c) (tp @ tshift tp' off, 0) stp)"
apply(induct stp arbitrary : a b c, simp add: t_steps.simps)
apply(simp add: t_steps.simps)
apply(case_tac "(t_step (a, b, c) (tp', 0))", simp)
apply(case_tac "aa = 0", simp add: state0_ind)
apply(subgoal_tac "(t_step (a + length tp div 2, b, c) 
                      (tp @ tshift tp' (length tp div 2), 0)) 
  = (aa + length tp div 2, ba, ca)", simp)
apply(rule tm_append_step_equal, auto)
done

(*********Begin: mop_up***************)
type_synonym mopup_type = "t_conf \<Rightarrow> nat list \<Rightarrow> nat \<Rightarrow> block list \<Rightarrow> bool"

fun mopup_stop :: "mopup_type"
  where
  "mopup_stop (s, l, r) lm n ires= 
        (\<exists> ln rn. l = Bk\<^bsup>ln\<^esup> @ Bk # Bk # ires \<and> r = <abc_lm_v lm n> @ Bk\<^bsup>rn\<^esup>)"

fun mopup_bef_erase_a :: "mopup_type"
  where
  "mopup_bef_erase_a (s, l, r) lm n ires= 
         (\<exists> ln m rn. l = Bk \<^bsup>ln\<^esup> @ Bk # Bk # ires \<and> 
                  r = Oc\<^bsup>m \<^esup>@ Bk # <(drop ((s + 1) div 2) lm)> @ Bk\<^bsup>rn\<^esup>)"

fun mopup_bef_erase_b :: "mopup_type"
  where
  "mopup_bef_erase_b (s, l, r) lm n ires = 
      (\<exists> ln m rn. l = Bk\<^bsup>ln\<^esup> @ Bk # Bk # ires \<and> r = Bk # Oc\<^bsup>m\<^esup> @ Bk # 
                                      <(drop (s div 2) lm)> @ Bk\<^bsup>rn\<^esup>)"


fun mopup_jump_over1 :: "mopup_type"
  where
  "mopup_jump_over1 (s, l, r) lm n ires = 
      (\<exists> ln m1 m2 rn. m1 + m2 = Suc (abc_lm_v lm n) \<and> 
        l = Oc\<^bsup>m1\<^esup> @ Bk\<^bsup>ln\<^esup> @ Bk # Bk # ires \<and> 
     (r = Oc\<^bsup>m2\<^esup> @ Bk # <(drop (Suc n) lm)> @ Bk\<^bsup>rn \<^esup>\<or> 
     (r = Oc\<^bsup>m2\<^esup> \<and> (drop (Suc n) lm) = [])))"

fun mopup_aft_erase_a :: "mopup_type"
  where
  "mopup_aft_erase_a (s, l, r) lm n ires = 
      (\<exists> lnl lnr rn (ml::nat list) m. 
          m = Suc (abc_lm_v lm n) \<and> l = Bk\<^bsup>lnr \<^esup>@ Oc\<^bsup>m \<^esup>@ Bk\<^bsup>lnl\<^esup> @ Bk # Bk # ires \<and> 
                                   (r = <ml> @ Bk\<^bsup>rn\<^esup>))"

fun mopup_aft_erase_b :: "mopup_type"
  where
  "mopup_aft_erase_b (s, l, r) lm n ires= 
   (\<exists> lnl lnr rn (ml::nat list) m. 
      m = Suc (abc_lm_v lm n) \<and> 
      l = Bk\<^bsup>lnr \<^esup>@ Oc\<^bsup>m \<^esup>@ Bk\<^bsup>lnl\<^esup> @ Bk # Bk # ires \<and> 
     (r = Bk # <ml> @ Bk\<^bsup>rn \<^esup>\<or>
      r = Bk # Bk # <ml> @ Bk\<^bsup>rn\<^esup>))"

fun mopup_aft_erase_c :: "mopup_type"
  where
  "mopup_aft_erase_c (s, l, r) lm n ires = 
 (\<exists> lnl lnr rn (ml::nat list) m. 
     m = Suc (abc_lm_v lm n) \<and> 
     l = Bk\<^bsup>lnr \<^esup>@ Oc\<^bsup>m \<^esup>@ Bk\<^bsup>lnl\<^esup> @ Bk # Bk # ires \<and> 
    (r = <ml> @ Bk\<^bsup>rn \<^esup>\<or> r = Bk # <ml> @ Bk\<^bsup>rn\<^esup>))"

fun mopup_left_moving :: "mopup_type"
  where
  "mopup_left_moving (s, l, r) lm n ires = 
  (\<exists> lnl lnr rn m.
     m = Suc (abc_lm_v lm n) \<and> 
   ((l = Bk\<^bsup>lnr \<^esup>@ Oc\<^bsup>m \<^esup>@ Bk\<^bsup>lnl\<^esup> @ Bk # Bk # ires \<and> r = Bk\<^bsup>rn\<^esup>) \<or>
    (l = Oc\<^bsup>m - 1\<^esup> @ Bk\<^bsup>lnl\<^esup> @ Bk # Bk # ires \<and> r = Oc # Bk\<^bsup>rn\<^esup>)))"

fun mopup_jump_over2 :: "mopup_type"
  where
  "mopup_jump_over2 (s, l, r) lm n ires = 
     (\<exists> ln rn m1 m2.
          m1 + m2 = Suc (abc_lm_v lm n) 
        \<and> r \<noteq> [] 
        \<and> (hd r = Oc \<longrightarrow> (l = Oc\<^bsup>m1\<^esup> @ Bk\<^bsup>ln\<^esup> @ Bk # Bk # ires \<and> r = Oc\<^bsup>m2\<^esup> @ Bk\<^bsup>rn\<^esup>)) 
        \<and> (hd r = Bk \<longrightarrow> (l = Bk\<^bsup>ln\<^esup> @ Bk # ires \<and> r = Bk # Oc\<^bsup>m1 + m2\<^esup> @ Bk\<^bsup>rn\<^esup>)))"


fun mopup_inv :: "mopup_type"
  where
  "mopup_inv (s, l, r) lm n ires = 
      (if s = 0 then mopup_stop (s, l, r) lm n ires
       else if s \<le> 2*n then
               if s mod 2 = 1 then mopup_bef_erase_a (s, l, r) lm n ires
                   else mopup_bef_erase_b (s, l, r) lm n ires
            else if s = 2*n + 1 then 
                mopup_jump_over1 (s, l, r) lm n ires
            else if s = 2*n + 2 then mopup_aft_erase_a (s, l, r) lm n ires
            else if s = 2*n + 3 then mopup_aft_erase_b (s, l, r) lm n ires
            else if s = 2*n + 4 then mopup_aft_erase_c (s, l, r) lm n ires
            else if s = 2*n + 5 then mopup_left_moving (s, l, r) lm n ires
            else if s = 2*n + 6 then mopup_jump_over2 (s, l, r) lm n ires
            else False)"

declare 
  mopup_jump_over2.simps[simp del] mopup_left_moving.simps[simp del]
  mopup_aft_erase_c.simps[simp del] mopup_aft_erase_b.simps[simp del] 
  mopup_aft_erase_a.simps[simp del] mopup_jump_over1.simps[simp del]
  mopup_bef_erase_a.simps[simp del] mopup_bef_erase_b.simps[simp del]
  mopup_stop.simps[simp del]

lemma mopup_fetch_0[simp]: 
     "(fetch (mop_bef n @ tshift mp_up (2 * n)) 0 b) = (Nop, 0)"
by(simp add: fetch.simps)

lemma mop_bef_length[simp]: "length (mop_bef n) = 4 * n"
apply(induct n, simp add: mop_bef.simps, simp add: mop_bef.simps)
done

thm findnth_nth
lemma mop_bef_nth: 
  "\<lbrakk>q < n; x < 4\<rbrakk> \<Longrightarrow> mop_bef n ! (4 * q + x) = 
                             mop_bef (Suc q) ! ((4 * q) + x)"
apply(induct n, simp)
apply(case_tac "q < n", simp add: mop_bef.simps, auto)
apply(simp add: nth_append)
apply(subgoal_tac "q = n", simp)
apply(arith)
done

lemma fetch_bef_erase_a_o[simp]: 
 "\<lbrakk>0 < s; s \<le> 2 * n; s mod 2 = Suc 0\<rbrakk>
  \<Longrightarrow> (fetch (mop_bef n @ tshift mp_up (2 * n)) s Oc) = (W0, s + 1)"
apply(subgoal_tac "\<exists> q. s = 2*q + 1", auto)
apply(subgoal_tac "length (mop_bef n) = 4*n")
apply(auto simp: fetch.simps nth_of.simps nth_append)
apply(subgoal_tac "mop_bef n ! (4 * q + 1) = 
                      mop_bef (Suc q) ! ((4 * q) + 1)", 
      simp add: mop_bef.simps nth_append)
apply(rule mop_bef_nth, auto)
done

lemma fetch_bef_erase_a_b[simp]:
  "\<lbrakk>n < length lm; 0 < s; s \<le> 2 * n; s mod 2 = Suc 0\<rbrakk>
   \<Longrightarrow>  (fetch (mop_bef n @ tshift mp_up (2 * n)) s Bk) = (R, s + 2)"
apply(subgoal_tac "\<exists> q. s = 2*q + 1", auto)
apply(subgoal_tac "length (mop_bef n) = 4*n")
apply(auto simp: fetch.simps nth_of.simps nth_append)
apply(subgoal_tac "mop_bef n ! (4 * q + 0) = 
                       mop_bef (Suc q) ! ((4 * q + 0))", 
      simp add: mop_bef.simps nth_append)
apply(rule mop_bef_nth, auto)
done

lemma fetch_bef_erase_b_b: 
  "\<lbrakk>n < length lm; 0 < s; s \<le> 2 * n; s mod 2 = 0\<rbrakk> \<Longrightarrow> 
     (fetch (mop_bef n @ tshift mp_up (2 * n)) s Bk) = (R, s - 1)"
apply(subgoal_tac "\<exists> q. s = 2 * q", auto)
apply(case_tac qa, simp, simp)
apply(auto simp: fetch.simps nth_of.simps nth_append)
apply(subgoal_tac "mop_bef n ! (4 * nat + 2) = 
                     mop_bef (Suc nat) ! ((4 * nat) + 2)", 
      simp add: mop_bef.simps nth_append)
apply(rule mop_bef_nth, auto)
done

lemma fetch_jump_over1_o: 
 "fetch (mop_bef n @ tshift mp_up (2 * n)) (Suc (2 * n)) Oc
  = (R, Suc (2 * n))"
apply(subgoal_tac "length (mop_bef n) = 4 * n")
apply(auto simp: fetch.simps nth_of.simps mp_up_def nth_append 
                 tshift.simps)
done

lemma fetch_jump_over1_b: 
 "fetch (mop_bef n @ tshift mp_up (2 * n)) (Suc (2 * n)) Bk 
 = (R, Suc (Suc (2 * n)))"
apply(subgoal_tac "length (mop_bef n) = 4 * n")
apply(auto simp: fetch.simps nth_of.simps mp_up_def 
                 nth_append tshift.simps)
done

lemma fetch_aft_erase_a_o: 
 "fetch (mop_bef n @ tshift mp_up (2 * n)) (Suc (Suc (2 * n))) Oc 
 = (W0, Suc (2 * n + 2))"
apply(subgoal_tac "length (mop_bef n) = 4 * n")
apply(auto simp: fetch.simps nth_of.simps mp_up_def 
                 nth_append tshift.simps)
done

lemma fetch_aft_erase_a_b: 
 "fetch (mop_bef n @ tshift mp_up (2 * n)) (Suc (Suc (2 * n))) Bk
  = (L, Suc (2 * n + 4))"
apply(subgoal_tac "length (mop_bef n) = 4 * n")
apply(auto simp: fetch.simps nth_of.simps mp_up_def 
                 nth_append tshift.simps)
done

lemma fetch_aft_erase_b_b: 
 "fetch (mop_bef n @ tshift mp_up (2 * n)) (2*n + 3) Bk
  = (R, Suc (2 * n + 3))"
apply(subgoal_tac "length (mop_bef n) = 4 * n")
apply(subgoal_tac "2*n + 3 = Suc (2*n + 2)", simp only: fetch.simps)
apply(auto simp: nth_of.simps mp_up_def nth_append tshift.simps)
done

lemma fetch_aft_erase_c_o: 
 "fetch (mop_bef n @ tshift mp_up (2 * n)) (2 * n + 4) Oc 
 = (W0, Suc (2 * n + 2))"
apply(subgoal_tac "length (mop_bef n) = 4 * n")
apply(subgoal_tac "2*n + 4 = Suc (2*n + 3)", simp only: fetch.simps)
apply(auto simp: nth_of.simps mp_up_def nth_append tshift.simps)
done

lemma fetch_aft_erase_c_b: 
 "fetch (mop_bef n @ tshift mp_up (2 * n)) (2 * n + 4) Bk 
 = (R, Suc (2 * n + 1))"
apply(subgoal_tac "length (mop_bef n) = 4 * n")
apply(subgoal_tac "2*n + 4 = Suc (2*n + 3)", simp only: fetch.simps)
apply(auto simp: nth_of.simps mp_up_def nth_append tshift.simps)
done

lemma fetch_left_moving_o: 
 "(fetch (mop_bef n @ tshift mp_up (2 * n)) (2 * n + 5) Oc) 
 = (L, 2*n + 6)"
apply(subgoal_tac "length (mop_bef n) = 4 * n")
apply(subgoal_tac "2*n + 5 = Suc (2*n + 4)", simp only: fetch.simps)
apply(auto simp: nth_of.simps mp_up_def nth_append tshift.simps)
done

lemma fetch_left_moving_b: 
 "(fetch (mop_bef n @ tshift mp_up (2 * n)) (2 * n + 5) Bk)
  = (L, 2*n + 5)"
apply(subgoal_tac "length (mop_bef n) = 4 * n")
apply(subgoal_tac "2*n + 5 = Suc (2*n + 4)", simp only: fetch.simps)
apply(auto simp: nth_of.simps mp_up_def nth_append tshift.simps)
done

lemma fetch_jump_over2_b:
  "(fetch (mop_bef n @ tshift mp_up (2 * n)) (2 * n + 6) Bk) 
 = (R, 0)"
apply(subgoal_tac "length (mop_bef n) = 4 * n")
apply(subgoal_tac "2*n + 6 = Suc (2*n + 5)", simp only: fetch.simps)
apply(auto simp: nth_of.simps mp_up_def nth_append tshift.simps)
done

lemma fetch_jump_over2_o: 
"(fetch (mop_bef n @ tshift mp_up (2 * n)) (2 * n + 6) Oc) 
 = (L, 2*n + 6)"
apply(subgoal_tac "length (mop_bef n) = 4 * n")
apply(subgoal_tac "2*n + 6 = Suc (2*n + 5)", simp only: fetch.simps)
apply(auto simp: nth_of.simps mp_up_def nth_append tshift.simps)
done

lemmas mopupfetchs = 
fetch_bef_erase_a_o fetch_bef_erase_a_b fetch_bef_erase_b_b 
fetch_jump_over1_o fetch_jump_over1_b fetch_aft_erase_a_o 
fetch_aft_erase_a_b fetch_aft_erase_b_b fetch_aft_erase_c_o 
fetch_aft_erase_c_b fetch_left_moving_o fetch_left_moving_b 
fetch_jump_over2_b fetch_jump_over2_o

lemma [simp]: 
"\<lbrakk>n < length lm; 0 < s; s mod 2 = Suc 0; 
  mopup_bef_erase_a (s, l, Oc # xs) lm n ires; 
  Suc s \<le> 2 * n\<rbrakk> \<Longrightarrow> 
  mopup_bef_erase_b (Suc s, l, Bk # xs) lm n ires"
apply(auto simp: mopup_bef_erase_a.simps mopup_bef_erase_b.simps )
apply(rule_tac x = "m - 1" in exI, rule_tac x = rn in exI)
apply(case_tac m, simp, simp)
done

lemma mopup_false1:
  "\<lbrakk>0 < s; s \<le> 2 * n; s mod 2 = Suc 0;  \<not> Suc s \<le> 2 * n\<rbrakk> 
  \<Longrightarrow> RR"
apply(arith)
done

lemma [simp]: 
 "\<lbrakk>n < length lm; 0 < s; s \<le> 2 * n; s mod 2 = Suc 0; 
   mopup_bef_erase_a (s, l, Oc # xs) lm n ires; r = Oc # xs\<rbrakk>
 \<Longrightarrow> (Suc s \<le> 2 * n \<longrightarrow> mopup_bef_erase_b (Suc s, l, Bk # xs) lm n ires)  \<and>
     (\<not> Suc s \<le> 2 * n \<longrightarrow> mopup_jump_over1 (Suc s, l, Bk # xs) lm n ires) "
apply(auto elim: mopup_false1)
done

lemma drop_abc_lm_v_simp[simp]: 
   "n < length lm \<Longrightarrow> drop n lm = abc_lm_v lm n # drop (Suc n) lm"
apply(auto simp: abc_lm_v.simps)
apply(drule drop_Suc_conv_tl, simp)
done
lemma [simp]: "(\<exists>rna. Bk\<^bsup>rn\<^esup> = Bk # Bk\<^bsup>rna\<^esup>) \<or> Bk\<^bsup>rn\<^esup> = []"
apply(case_tac rn, simp, auto)
done

lemma [simp]: "\<exists>lna. Bk # Bk\<^bsup>ln\<^esup> = Bk\<^bsup>lna\<^esup>"
apply(rule_tac x = "Suc ln" in exI, auto)
done

lemma mopup_bef_erase_a_2_jump_over[simp]: 
 "\<lbrakk>n < length lm; 0 < s; s mod 2 = Suc 0; 
   mopup_bef_erase_a (s, l, Bk # xs) lm n ires; Suc s = 2 * n\<rbrakk> 
\<Longrightarrow> mopup_jump_over1 (Suc (2 * n), Bk # l, xs) lm n ires"
apply(auto simp: mopup_bef_erase_a.simps mopup_jump_over1.simps)
apply(case_tac m, simp)
apply(rule_tac x = "Suc ln" in exI, rule_tac x = 0 in exI, 
      simp add: tape_of_nl_abv)
apply(case_tac "drop (Suc n) lm", auto simp: tape_of_nat_list.simps )
done

lemma Suc_Suc_div:  "\<lbrakk>0 < s; s mod 2 = Suc 0; Suc (Suc s) \<le> 2 * n\<rbrakk>
           \<Longrightarrow> (Suc (Suc (s div 2))) \<le> n"
apply(arith)
done

lemma mopup_bef_erase_a_2_a[simp]: 
 "\<lbrakk>n < length lm; 0 < s; s mod 2 = Suc 0; 
   mopup_bef_erase_a (s, l, Bk # xs) lm n ires; 
   Suc (Suc s) \<le> 2 * n\<rbrakk> \<Longrightarrow> 
   mopup_bef_erase_a (Suc (Suc s), Bk # l, xs) lm n ires"
apply(auto simp: mopup_bef_erase_a.simps )
apply(subgoal_tac "drop (Suc (Suc (s div 2))) lm \<noteq> []")
apply(case_tac m, simp)
apply(rule_tac x = "Suc (abc_lm_v lm (Suc (s div 2)))" in exI, 
      rule_tac x = rn in exI, simp, simp)
apply(subgoal_tac "(Suc (Suc (s div 2))) \<le> n", simp, 
      rule_tac Suc_Suc_div, auto)
done

lemma mopup_false2: 
 "\<lbrakk>n < length lm; 0 < s; s \<le> 2 * n; 
   s mod 2 = Suc 0; Suc s \<noteq> 2 * n;
   \<not> Suc (Suc s) \<le> 2 * n\<rbrakk> \<Longrightarrow> RR"
apply(arith)
done

lemma [simp]:
  "\<lbrakk>n < length lm; 0 < s; s \<le> 2 * n; 
   s mod 2 = Suc 0; 
   mopup_bef_erase_a (s, l, Bk # xs) lm n ires; 
   r = Bk # xs\<rbrakk>
 \<Longrightarrow> (Suc s = 2 * n \<longrightarrow> 
             mopup_jump_over1 (Suc (2 * n), Bk # l, xs) lm n ires) \<and>
     (Suc s \<noteq> 2 * n \<longrightarrow> 
       (Suc (Suc s) \<le> 2 * n \<longrightarrow> 
          mopup_bef_erase_a (Suc (Suc s), Bk # l, xs) lm n ires) \<and> 
       (\<not> Suc (Suc s) \<le> 2 * n \<longrightarrow> 
          mopup_aft_erase_a (Suc (Suc s), Bk # l, xs) lm n ires))"
apply(auto elim: mopup_false2)
done

lemma [simp]: "mopup_bef_erase_a (s, l, []) lm n ires \<Longrightarrow> 
                        mopup_bef_erase_a (s, l, [Bk]) lm n ires"
apply(auto simp: mopup_bef_erase_a.simps)
done

lemma [simp]:
   "\<lbrakk>n < length lm; 0 < s; s \<le> 2 * n; s mod 2 = Suc 0;
     mopup_bef_erase_a (s, l, []) lm n ires; r = []\<rbrakk>
    \<Longrightarrow> (Suc s = 2 * n \<longrightarrow> 
              mopup_jump_over1 (Suc (2 * n), Bk # l, []) lm n ires) \<and>
        (Suc s \<noteq> 2 * n \<longrightarrow> 
             (Suc (Suc s) \<le> 2 * n \<longrightarrow> 
                 mopup_bef_erase_a (Suc (Suc s), Bk # l, []) lm n ires) \<and>
             (\<not> Suc (Suc s) \<le> 2 * n \<longrightarrow> 
                 mopup_aft_erase_a (Suc (Suc s), Bk # l, []) lm n ires))"
apply(auto)
done

lemma "mopup_bef_erase_b (s, l, Oc # xs) lm n ires \<Longrightarrow> l \<noteq> []"
apply(auto simp: mopup_bef_erase_b.simps)
done

lemma [simp]: "mopup_bef_erase_b (s, l, Oc # xs) lm n ires = False"
apply(auto simp: mopup_bef_erase_b.simps )
done
 
lemma [simp]: "\<lbrakk>0 < s; s \<le> 2 *n; s mod 2 \<noteq> Suc 0\<rbrakk> \<Longrightarrow> 
                                      (s - Suc 0) mod 2 = Suc 0"
apply(arith)
done

lemma [simp]: "\<lbrakk>0 < s; s \<le> 2 *n; s mod 2 \<noteq> Suc 0\<rbrakk> \<Longrightarrow>
                                       s - Suc 0 \<le> 2 * n"
apply(simp)
done

lemma [simp]: "\<lbrakk>0 < s; s \<le> 2 *n; s mod 2 \<noteq> Suc 0\<rbrakk> \<Longrightarrow> \<not> s \<le> Suc 0"
apply(arith)
done

lemma [simp]: "\<lbrakk>n < length lm; 0 < s; s \<le> 2 * n; 
               s mod 2 \<noteq> Suc 0; 
               mopup_bef_erase_b (s, l, Bk # xs) lm n ires; r = Bk # xs\<rbrakk> 
           \<Longrightarrow> mopup_bef_erase_a (s - Suc 0, Bk # l, xs) lm n ires"
apply(auto simp: mopup_bef_erase_b.simps mopup_bef_erase_a.simps)
done

lemma [simp]: "\<lbrakk>mopup_bef_erase_b (s, l, []) lm n ires\<rbrakk> \<Longrightarrow> 
                   mopup_bef_erase_a (s - Suc 0, Bk # l, []) lm n ires"
apply(auto simp: mopup_bef_erase_b.simps mopup_bef_erase_a.simps)
done

lemma [simp]: 
   "\<lbrakk>n < length lm;
    mopup_jump_over1 (Suc (2 * n), l, Oc # xs) lm n ires;
    r = Oc # xs\<rbrakk>
  \<Longrightarrow> mopup_jump_over1 (Suc (2 * n), Oc # l, xs) lm n ires"
apply(auto simp: mopup_jump_over1.simps)
apply(rule_tac x = ln in exI, rule_tac x = "Suc m1" in exI,
       rule_tac x = "m2 - 1" in exI)
apply(case_tac "m2", simp, simp, rule_tac x = rn in exI, simp)
apply(rule_tac x = ln in exI, rule_tac x = "Suc m1" in exI, 
      rule_tac x = "m2 - 1" in exI)
apply(case_tac m2, simp, simp)
done

lemma mopup_jump_over1_2_aft_erase_a[simp]:  
 "\<lbrakk>n < length lm; mopup_jump_over1 (Suc (2 * n), l, Bk # xs) lm n ires\<rbrakk>
  \<Longrightarrow> mopup_aft_erase_a (Suc (Suc (2 * n)), Bk # l, xs) lm n ires"
apply(simp only: mopup_jump_over1.simps mopup_aft_erase_a.simps)
apply(erule_tac exE)+
apply(rule_tac x = ln in exI, rule_tac x = "Suc 0" in exI)
apply(case_tac m2, simp)
apply(rule_tac x = rn in exI, rule_tac x = "drop (Suc n) lm" in exI, 
      simp)
apply(simp)
done

lemma [simp]: 
 "\<lbrakk>n < length lm; mopup_jump_over1 (Suc (2 * n), l, []) lm n ires\<rbrakk> \<Longrightarrow> 
    mopup_aft_erase_a (Suc (Suc (2 * n)), Bk # l, []) lm n ires"
apply(rule mopup_jump_over1_2_aft_erase_a, simp)
apply(auto simp: mopup_jump_over1.simps)
apply(rule_tac x = ln in exI, rule_tac x = m1 in exI, 
      rule_tac x = m2 in exI, simp add: )
apply(rule_tac x = 0 in exI, auto)
done

lemma [simp]: 
 "\<lbrakk>n < length lm; 
   mopup_aft_erase_a (Suc (Suc (2 * n)), l, Oc # xs) lm n ires\<rbrakk> 
 \<Longrightarrow> mopup_aft_erase_b (Suc (Suc (Suc (2 * n))), l, Bk # xs) lm n ires"
apply(auto simp: mopup_aft_erase_a.simps mopup_aft_erase_b.simps )
apply(case_tac ml, simp, case_tac rn, simp, simp)
apply(case_tac list, auto simp: tape_of_nl_abv 
                                tape_of_nat_list.simps )
apply(case_tac a, simp, rule_tac x = rn in exI, 
      rule_tac x = "[]" in exI,
       simp add: tape_of_nat_list.simps, simp)
apply(rule_tac x = rn in exI, rule_tac x = "[nat]" in exI, 
      simp add: tape_of_nat_list.simps )
apply(case_tac a, simp, rule_tac x = rn in exI, 
       rule_tac x = "aa # lista" in exI, simp, simp)
apply(rule_tac x = rn in exI, rule_tac x = "nat # aa # lista" in exI, 
       simp add: tape_of_nat_list.simps )
done

lemma [simp]:
  "mopup_aft_erase_a (Suc (Suc (2 * n)), l, Bk # xs) lm n ires \<Longrightarrow> l \<noteq> []"
apply(auto simp: mopup_aft_erase_a.simps)
done

lemma [simp]:
  "\<lbrakk>n < length lm;
    mopup_aft_erase_a (Suc (Suc (2 * n)), l, Bk # xs) lm n ires\<rbrakk>
  \<Longrightarrow> mopup_left_moving (5 + 2 * n, tl l, hd l # Bk # xs) lm n ires"
apply(simp only: mopup_aft_erase_a.simps mopup_left_moving.simps)
apply(erule exE)+
apply(case_tac lnr, simp)
apply(rule_tac x = lnl in exI, simp, rule_tac x = rn in exI, simp)
apply(subgoal_tac "ml = []", simp)
apply(rule_tac xs = xs and rn = rn in BkCons_nil, simp, auto)
apply(subgoal_tac "ml = []", auto)
apply(rule_tac xs = xs and rn = rn in BkCons_nil, simp)
done

lemma [simp]:
  "mopup_aft_erase_a (Suc (Suc (2 * n)), l, []) lm n ires \<Longrightarrow> l \<noteq> []"
apply(simp only: mopup_aft_erase_a.simps)
apply(erule exE)+
apply(auto)
done

lemma [simp]:
  "\<lbrakk>n < length lm; mopup_aft_erase_a (Suc (Suc (2 * n)), l, []) lm n ires\<rbrakk>
  \<Longrightarrow> mopup_left_moving (5 + 2 * n, tl l, [hd l]) lm n ires"
apply(simp only: mopup_aft_erase_a.simps mopup_left_moving.simps)
apply(erule exE)+
apply(subgoal_tac "ml = [] \<and> rn = 0", erule conjE, erule conjE, simp)
apply(case_tac lnr, simp, rule_tac x = lnl in exI, simp, 
      rule_tac x = 0 in exI, simp)
apply(rule_tac x = lnl in exI, rule_tac x = nat in exI, 
      rule_tac x = "Suc 0" in exI, simp)
apply(case_tac ml, simp, case_tac rn, simp, simp)
apply(case_tac list, auto simp: tape_of_nl_abv tape_of_nat_list.simps)
done

lemma [simp]: "mopup_aft_erase_b (2 * n + 3, l, Oc # xs) lm n ires = False"
apply(auto simp: mopup_aft_erase_b.simps )
done

lemma [simp]: 
 "\<lbrakk>n < length lm; 
   mopup_aft_erase_c (2 * n + 4, l, Oc # xs) lm n ires\<rbrakk>
  \<Longrightarrow> mopup_aft_erase_b (Suc (Suc (Suc (2 * n))), l, Bk # xs) lm n ires"
apply(auto simp: mopup_aft_erase_c.simps mopup_aft_erase_b.simps )
apply(case_tac ml, simp, case_tac rn, simp, simp, simp)
apply(case_tac list, auto simp: tape_of_nl_abv 
                        tape_of_nat_list.simps tape_of_nat_abv )
apply(case_tac a, rule_tac x = rn in exI, 
      rule_tac x = "[]" in exI, simp add: tape_of_nat_list.simps)
apply(rule_tac x = rn in exI, rule_tac x = "[nat]" in exI, 
      simp add: tape_of_nat_list.simps )
apply(case_tac a, simp, rule_tac x = rn in exI, 
      rule_tac x = "aa # lista" in exI, simp)
apply(rule_tac x = rn in exI, rule_tac x = "nat # aa # lista" in exI, 
      simp add: tape_of_nat_list.simps )
done

lemma mopup_aft_erase_c_aft_erase_a[simp]: 
 "\<lbrakk>n < length lm; mopup_aft_erase_c (2 * n + 4, l, Bk # xs) lm n ires\<rbrakk> 
 \<Longrightarrow> mopup_aft_erase_a (Suc (Suc (2 * n)), Bk # l, xs) lm n ires"
apply(simp only: mopup_aft_erase_c.simps mopup_aft_erase_a.simps )
apply(erule_tac exE)+
apply(erule conjE, erule conjE, erule disjE)
apply(subgoal_tac "ml = []", simp, case_tac rn, 
      simp, simp, rule conjI)
apply(rule_tac x = lnl in exI, rule_tac x = "Suc lnr" in exI, simp)
apply(rule_tac x = nat in exI, rule_tac x = "[]" in exI, simp)
apply(rule_tac xs = xs and rn = rn in BkCons_nil, simp, simp, 
      rule conjI)
apply(rule_tac x = lnl in exI, rule_tac x = "Suc lnr" in exI, simp)
apply(rule_tac x = rn in exI, rule_tac x = "ml" in exI, simp)
done

lemma [simp]: 
 "\<lbrakk>n < length lm; mopup_aft_erase_c (2 * n + 4, l, []) lm n ires\<rbrakk> 
 \<Longrightarrow> mopup_aft_erase_a (Suc (Suc (2 * n)), Bk # l, []) lm n ires"
apply(rule mopup_aft_erase_c_aft_erase_a, simp)
apply(simp only: mopup_aft_erase_c.simps)
apply(erule exE)+
apply(rule_tac x = lnl in exI, rule_tac x = lnr in exI, simp add: )
apply(rule_tac x = 0 in exI, rule_tac x = "[]" in exI, simp)
done

lemma mopup_aft_erase_b_2_aft_erase_c[simp]:
  "\<lbrakk>n < length lm; mopup_aft_erase_b (2 * n + 3, l, Bk # xs) lm n ires\<rbrakk>  
 \<Longrightarrow> mopup_aft_erase_c (4 + 2 * n, Bk # l, xs) lm n ires"
apply(auto simp: mopup_aft_erase_b.simps mopup_aft_erase_c.simps)
apply(rule_tac x = "lnl" in exI, rule_tac x = "Suc lnr" in exI, simp)
apply(rule_tac x = "lnl" in exI, rule_tac x = "Suc lnr" in exI, simp)
done

lemma [simp]: 
 "\<lbrakk>n < length lm; mopup_aft_erase_b (2 * n + 3, l, []) lm n ires\<rbrakk> 
 \<Longrightarrow> mopup_aft_erase_c (4 + 2 * n, Bk # l, []) lm n ires"
apply(rule_tac mopup_aft_erase_b_2_aft_erase_c, simp)
apply(simp add: mopup_aft_erase_b.simps)
done

lemma [simp]: 
    "mopup_left_moving (2 * n + 5, l, Oc # xs) lm n ires \<Longrightarrow> l \<noteq> []"
apply(auto simp: mopup_left_moving.simps)
done

lemma [simp]:  
 "\<lbrakk>n < length lm; mopup_left_moving (2 * n + 5, l, Oc # xs) lm n ires\<rbrakk>
  \<Longrightarrow> mopup_jump_over2 (2 * n + 6, tl l, hd l # Oc # xs) lm n ires"
apply(simp only: mopup_left_moving.simps mopup_jump_over2.simps)
apply(erule_tac exE)+
apply(erule conjE, erule disjE, erule conjE)
apply(case_tac rn, simp, simp add: )
apply(case_tac "hd l", simp add:  )
apply(case_tac "abc_lm_v lm n", simp)
apply(rule_tac x = "lnl" in exI, rule_tac x = rn in exI, 
      rule_tac x = "Suc 0" in exI, rule_tac x = 0 in exI)
apply(case_tac lnl, simp, simp, simp add: exp_ind[THEN sym], simp)
apply(case_tac "abc_lm_v lm n", simp)
apply(case_tac lnl, simp, simp)
apply(rule_tac x = lnl in exI, rule_tac x = rn in exI)
apply(rule_tac x = nat in exI, rule_tac x = "Suc (Suc 0)" in exI, simp)
done

lemma [simp]: "mopup_left_moving (2 * n + 5, l, xs) lm n ires \<Longrightarrow> l \<noteq> []"
apply(auto simp: mopup_left_moving.simps)
done

lemma [simp]:
  "\<lbrakk>n < length lm; mopup_left_moving (2 * n + 5, l, Bk # xs) lm n ires\<rbrakk> 
 \<Longrightarrow> mopup_left_moving (2 * n + 5, tl l, hd l # Bk # xs) lm n ires"
apply(simp only: mopup_left_moving.simps)
apply(erule exE)+
apply(case_tac lnr, simp)
apply(rule_tac x = lnl in exI, rule_tac x = 0 in exI, 
      rule_tac x = rn in exI, simp, simp)
apply(rule_tac x = lnl in exI, rule_tac x = nat in exI, simp)
done

lemma [simp]: 
"\<lbrakk>n < length lm; mopup_left_moving (2 * n + 5, l, []) lm n ires\<rbrakk>
    \<Longrightarrow> mopup_left_moving (2 * n + 5, tl l, [hd l]) lm n ires"
apply(simp only: mopup_left_moving.simps)
apply(erule exE)+
apply(case_tac lnr, simp)
apply(rule_tac x = lnl in exI, rule_tac x = 0 in exI, 
      rule_tac x = 0 in exI, simp, auto)
done

lemma [simp]: 
 "mopup_jump_over2 (2 * n + 6, l, Oc # xs) lm n ires \<Longrightarrow> l \<noteq> []"
apply(auto simp: mopup_jump_over2.simps )
done

lemma [intro]: "\<exists>lna. Bk # Bk\<^bsup>ln\<^esup> = Bk\<^bsup>lna\<^esup> @ [Bk]"
apply(simp only: exp_ind[THEN sym], auto)
done

lemma [simp]: 
"\<lbrakk>n < length lm; mopup_jump_over2 (2 * n + 6, l, Oc # xs) lm n ires\<rbrakk>
 \<Longrightarrow>  mopup_jump_over2 (2 * n + 6, tl l, hd l # Oc # xs) lm n ires"
apply(simp only: mopup_jump_over2.simps)
apply(erule_tac exE)+
apply(simp add:  , erule conjE, erule_tac conjE)
apply(case_tac m1, simp)
apply(rule_tac x = ln in exI, rule_tac x = rn in exI, 
      rule_tac x = 0 in exI, simp)
apply(case_tac ln, simp, simp, simp only: exp_ind[THEN sym], simp)
apply(rule_tac x = ln in exI, rule_tac x = rn in exI, 
      rule_tac x = nat in exI, rule_tac x = "Suc m2" in exI, simp)
done

lemma [simp]: "\<exists>rna. Oc # Oc\<^bsup>a\<^esup> @ Bk\<^bsup>rn\<^esup> = <a> @ Bk\<^bsup>rna\<^esup>"
apply(case_tac a, auto simp: tape_of_nat_abv )
done

lemma [simp]: 
 "\<lbrakk>n < length lm; mopup_jump_over2 (2 * n + 6, l, Bk # xs) lm n ires\<rbrakk> 
  \<Longrightarrow> mopup_stop (0, Bk # l, xs) lm n ires"
apply(auto simp: mopup_jump_over2.simps mopup_stop.simps)
done

lemma [simp]: "mopup_jump_over2 (2 * n + 6, l, []) lm n ires = False"
apply(simp only: mopup_jump_over2.simps, simp)
done

lemma mopup_inv_step:
  "\<lbrakk>n < length lm; mopup_inv (s, l, r) lm n ires\<rbrakk>
  \<Longrightarrow> mopup_inv (t_step (s, l, r) 
       ((mop_bef n @ tshift mp_up (2 * n)), 0)) lm n ires"
apply(auto split:if_splits simp add:t_step.simps,
      tactic {* ALLGOALS (resolve_tac [@{thm "fetch_intro"}]) *})
apply(simp_all add: mopupfetchs new_tape.simps)
done

declare mopup_inv.simps[simp del]

lemma mopup_inv_steps: 
"\<lbrakk>n < length lm; mopup_inv (s, l, r) lm n ires\<rbrakk> \<Longrightarrow> 
     mopup_inv (t_steps (s, l, r) 
                   ((mop_bef n @ tshift mp_up (2 * n)), 0) stp) lm n ires"
apply(induct stp, simp add: t_steps.simps)
apply(simp add: t_steps_ind)
apply(case_tac "(t_steps (s, l, r) 
                (mop_bef n @ tshift mp_up (2 * n), 0) stp)", simp)
apply(rule_tac mopup_inv_step, simp, simp)
done

lemma [simp]: 
 "\<lbrakk>n < length lm; Suc 0 \<le> n\<rbrakk> \<Longrightarrow> 
            mopup_bef_erase_a (Suc 0, Bk\<^bsup>ln\<^esup> @ Bk # Bk # ires, <lm> @ Bk\<^bsup>rn\<^esup>) lm n ires"
apply(auto simp: mopup_bef_erase_a.simps  abc_lm_v.simps)
apply(case_tac lm, simp, case_tac list, simp, simp)
apply(rule_tac x = "Suc a" in exI, rule_tac x = rn in exI, simp)
done
  
lemma [simp]:
  "lm \<noteq> [] \<Longrightarrow> mopup_jump_over1 (Suc 0, Bk\<^bsup>ln\<^esup> @ Bk # Bk # ires, <lm> @ Bk\<^bsup>rn\<^esup>) lm 0  ires"
apply(auto simp: mopup_jump_over1.simps)
apply(rule_tac x = ln in exI, rule_tac x = 0 in exI, simp add: )
apply(case_tac lm, simp, simp add: abc_lm_v.simps)
apply(case_tac rn, simp)
apply(case_tac list, rule_tac disjI2, 
      simp add: tape_of_nl_abv tape_of_nat_list.simps)
apply(rule_tac disjI1,
      simp add: tape_of_nl_abv tape_of_nat_list.simps )
apply(rule_tac disjI1, case_tac list, 
      simp add: tape_of_nl_abv tape_of_nat_list.simps, 
      rule_tac x = nat in exI, simp)
apply(simp add: tape_of_nl_abv tape_of_nat_list.simps )
done

lemma mopup_init: 
 "\<lbrakk>n < length lm; crsp_l ly (as, lm) (ac, l, r) ires\<rbrakk> \<Longrightarrow> 
                               mopup_inv (Suc 0, l, r) lm n ires"
apply(auto simp: crsp_l.simps mopup_inv.simps)
apply(case_tac n, simp, auto simp: mopup_bef_erase_a.simps )
apply(rule_tac x = "Suc (hd lm)" in exI, rule_tac x = rn in exI, simp)
apply(case_tac lm, simp, case_tac list, simp, case_tac lista, simp add: abc_lm_v.simps)
apply(simp add: tape_of_nl_abv tape_of_nat_list.simps abc_lm_v.simps)
apply(simp add: mopup_jump_over1.simps)
apply(rule_tac x = 0 in exI, rule_tac x = 0 in exI, auto)
apply(case_tac [!] n, simp_all)
apply(case_tac [!] lm, simp, case_tac list, simp)
apply(case_tac rn, simp add: tape_of_nl_abv tape_of_nat_list.simps abc_lm_v.simps)
apply(erule_tac x = nat in allE, simp add: tape_of_nl_abv tape_of_nat_list.simps abc_lm_v.simps)
apply(simp add: abc_lm_v.simps, auto)
apply(case_tac list, simp_all add: tape_of_nl_abv tape_of_nat_list.simps abc_lm_v.simps) 
apply(erule_tac x = rn in allE, simp_all)
done

fun abc_mopup_stage1 :: "t_conf \<Rightarrow> nat \<Rightarrow> nat"
  where
  "abc_mopup_stage1 (s, l, r) n = 
           (if s > 0 \<and> s \<le> 2*n then 6
            else if s = 2*n + 1 then 4
            else if s \<ge> 2*n + 2 \<and> s \<le> 2*n + 4 then 3
            else if s = 2*n + 5 then 2
            else if s = 2*n + 6 then 1
            else 0)"

fun abc_mopup_stage2 :: "t_conf \<Rightarrow> nat \<Rightarrow> nat"
  where
  "abc_mopup_stage2 (s, l, r) n = 
           (if s > 0 \<and> s \<le> 2*n then length r
            else if s = 2*n + 1 then length r
            else if s = 2*n + 5 then length l
            else if s = 2*n + 6 then length l
            else if s \<ge> 2*n + 2 \<and> s \<le> 2*n + 4 then length r
            else 0)"

fun abc_mopup_stage3 :: "t_conf \<Rightarrow> nat \<Rightarrow> nat"
  where
  "abc_mopup_stage3 (s, l, r) n = 
          (if s > 0 \<and> s \<le> 2*n then 
              if hd r = Bk then 0
              else 1
           else if s = 2*n + 2 then 1 
           else if s = 2*n + 3 then 0
           else if s = 2*n + 4 then 2
           else 0)"

fun abc_mopup_measure :: "(t_conf \<times> nat) \<Rightarrow> (nat \<times> nat \<times> nat)"
  where
  "abc_mopup_measure (c, n) = 
    (abc_mopup_stage1 c n, abc_mopup_stage2 c n, 
                                       abc_mopup_stage3 c n)"

definition abc_mopup_LE ::
   "(((nat \<times> block list \<times> block list) \<times> nat) \<times> 
    ((nat \<times> block list \<times> block list) \<times> nat)) set"
  where
  "abc_mopup_LE \<equiv> (inv_image lex_triple abc_mopup_measure)"

lemma wf_abc_mopup_le[intro]: "wf abc_mopup_LE"
by(auto intro:wf_inv_image wf_lex_triple simp:abc_mopup_LE_def)

lemma [simp]: "mopup_bef_erase_a (a, aa, []) lm n ires = False"
apply(auto simp: mopup_bef_erase_a.simps)
done

lemma [simp]: "mopup_bef_erase_b (a, aa, []) lm n ires = False"
apply(auto simp: mopup_bef_erase_b.simps) 
done

lemma [simp]: "mopup_aft_erase_b (2 * n + 3, aa, []) lm n ires = False"
apply(auto simp: mopup_aft_erase_b.simps)
done

lemma mopup_halt_pre: 
 "\<lbrakk>n < length lm; mopup_inv (Suc 0, l, r) lm n ires; wf abc_mopup_LE\<rbrakk>
 \<Longrightarrow>  \<forall>na. \<not> (\<lambda>(s, l, r) n. s = 0) (t_steps (Suc 0, l, r)
      (mop_bef n @ tshift mp_up (2 * n), 0) na) n \<longrightarrow>
       ((t_steps (Suc 0, l, r) (mop_bef n @ tshift mp_up (2 * n), 0) 
        (Suc na), n),
       t_steps (Suc 0, l, r) (mop_bef n @ tshift mp_up (2 * n), 0)
         na, n) \<in> abc_mopup_LE"
apply(rule allI, rule impI, simp add: t_steps_ind)
apply(subgoal_tac "mopup_inv (t_steps (Suc 0, l, r) 
                     (mop_bef n @ tshift mp_up (2 * n), 0) na) lm n ires")
apply(case_tac "(t_steps (Suc 0, l, r) 
               (mop_bef n @ tshift mp_up (2 * n), 0) na)",  simp)
proof -
  fix na a b c
  assume  "n < length lm" "mopup_inv (a, b, c) lm n ires" "0 < a"
  thus "((t_step (a, b, c) (mop_bef n @ tshift mp_up (2 * n), 0), n),
         (a, b, c), n) \<in> abc_mopup_LE"
    apply(auto split:if_splits simp add:t_step.simps mopup_inv.simps,
      tactic {* ALLGOALS (resolve_tac [@{thm "fetch_intro"}]) *})
    apply(simp_all add: mopupfetchs new_tape.simps abc_mopup_LE_def 
                   lex_triple_def lex_pair_def )
    done
next
  fix na
  assume "n < length lm" "mopup_inv (Suc 0, l, r) lm n ires"
  thus "mopup_inv (t_steps (Suc 0, l, r) 
       (mop_bef n @ tshift mp_up (2 * n), 0) na) lm n ires"
    apply(rule mopup_inv_steps)
    done
qed

lemma mopup_halt: "\<lbrakk>n < length lm; crsp_l ly (as, lm) (s, l, r) ires\<rbrakk> \<Longrightarrow> 
  \<exists> stp. (\<lambda> (s, l, r). s = 0) (t_steps (Suc 0, l, r) 
        ((mop_bef n @ tshift mp_up (2 * n)), 0) stp)"
apply(subgoal_tac "mopup_inv (Suc 0, l, r) lm n ires")
apply(insert wf_abc_mopup_le)
apply(insert halt_lemma[of abc_mopup_LE 
    "\<lambda> ((s, l, r), n). s = 0" 
    "\<lambda> stp. (t_steps (Suc 0, l, r) ((mop_bef n @ tshift mp_up (2 * n))
           , 0) stp, n)"], auto)
apply(insert mopup_halt_pre[of n lm l r], simp, erule exE)
apply(rule_tac x = na in exI, case_tac "(t_steps (Suc 0, l, r) 
          (mop_bef n @ tshift mp_up (2 * n), 0) na)", simp)
apply(rule_tac mopup_init, auto)
done
(***End: mopup stop****)

lemma mopup_halt_conf_pre: 
 "\<lbrakk>n < length lm; crsp_l ly (as, lm) (s, l, r) ires\<rbrakk> 
  \<Longrightarrow> \<exists> na. (\<lambda> (s', l', r').  s' = 0 \<and> mopup_stop (s', l', r') lm n ires)
      (t_steps (Suc 0, l, r) 
            ((mop_bef n @ tshift mp_up (2 * n)), 0) na)"
apply(subgoal_tac "\<exists> stp. (\<lambda> (s, l, r). s = 0) 
 (t_steps (Suc 0, l, r) ((mop_bef n @ tshift mp_up (2 * n)), 0) stp)",
       erule exE)
apply(rule_tac x = stp in exI, 
      case_tac "(t_steps (Suc 0, l, r) 
          (mop_bef n @ tshift mp_up (2 * n), 0) stp)", simp)
apply(subgoal_tac " mopup_inv (Suc 0, l, r) lm n ires")
apply(subgoal_tac "mopup_inv (t_steps (Suc 0, l, r) 
            (mop_bef n @ tshift mp_up (2 * n), 0) stp) lm n ires", simp)
apply(simp only: mopup_inv.simps)
apply(rule_tac mopup_inv_steps, simp, simp)
apply(rule_tac mopup_init, simp, simp)
apply(rule_tac mopup_halt, simp, simp)
done

lemma  mopup_halt_conf:
  assumes len: "n < length lm"
  and correspond: "crsp_l ly (as, lm) (s, l, r) ires"
  shows 
  "\<exists> na. (\<lambda> (s', l', r'). ((\<exists>ln rn. s' = 0 \<and> l' = Bk\<^bsup>ln\<^esup> @ Bk # Bk # ires
                           \<and> r' = Oc\<^bsup>Suc (abc_lm_v lm n)\<^esup> @ Bk\<^bsup>rn\<^esup>)))
             (t_steps (Suc 0, l, r) 
                  ((mop_bef n @ tshift mp_up (2 * n)), 0) na)"
using len correspond mopup_halt_conf_pre[of n lm ly as s l r ires]
apply(simp add: mopup_stop.simps tape_of_nat_abv tape_of_nat_list.simps)
done

subsection {* Final results about Abacus machine *}

lemma mopup_halt_bef: "\<lbrakk>n < length lm; crsp_l ly (as, lm) (s, l, r) ires\<rbrakk> 
    \<Longrightarrow> \<exists>stp. (\<lambda>(s, l, r). s \<noteq> 0 \<and> ((\<lambda> (s', l', r'). s' = 0)
   (t_step (s, l, r) (mop_bef n @ tshift mp_up (2 * n), 0))))
    (t_steps (Suc 0, l, r) (mop_bef n @ tshift mp_up (2 * n), 0) stp)"
apply(insert mopup_halt[of n lm ly as s l r ires], simp, erule_tac exE)
proof -
  fix stp
  assume "n < length lm" 
         "crsp_l ly (as, lm) (s, l, r) ires" 
         "(\<lambda>(s, l, r). s = 0) 
            (t_steps (Suc 0, l, r) 
              (mop_bef n @ tshift mp_up (2 * n), 0) stp)"
  thus "\<exists>stp. (\<lambda>(s, ab). 0 < s \<and> (\<lambda>(s', l', r'). s' = 0) 
   (t_step (s, ab) (mop_bef n @ tshift mp_up (2 * n), 0))) 
    (t_steps (Suc 0, l, r) (mop_bef n @ tshift mp_up (2 * n), 0) stp)"
  proof(induct stp, simp add: t_steps.simps, simp)
    fix stpa
    assume h1: 
      "(\<lambda>(s, l, r). s = 0) (t_steps (Suc 0, l, r) 
           (mop_bef n @ tshift mp_up (2 * n), 0) stpa) \<Longrightarrow>
       \<exists>stp. (\<lambda>(s, ab). 0 < s \<and> (\<lambda>(s', l', r'). s' = 0) 
         (t_step (s, ab) (mop_bef n @ tshift mp_up (2 * n), 0))) 
            (t_steps (Suc 0, l, r) 
              (mop_bef n @ tshift mp_up (2 * n), 0) stp)"
      and h2: 
        "(\<lambda>(s, l, r). s = 0) (t_steps (Suc 0, l, r) 
                    (mop_bef n @ tshift mp_up (2 * n), 0) (Suc stpa))"
         "n < length lm" 
         "crsp_l ly (as, lm) (s, l, r) ires"
    thus "\<exists>stp. (\<lambda>(s, ab). 0 < s \<and> (\<lambda>(s', l', r'). s' = 0) 
             (t_step (s, ab) (mop_bef n @ tshift mp_up (2 * n), 0))) (
                t_steps (Suc 0, l, r) 
                  (mop_bef n @ tshift mp_up (2 * n), 0) stp)"
      apply(case_tac "(\<lambda>(s, l, r). s = 0) (t_steps (Suc 0, l, r) 
                     (mop_bef n @ tshift mp_up (2 * n), 0) stpa)", 
            simp)
      apply(rule_tac x = "stpa" in exI)
      apply(case_tac "(t_steps (Suc 0, l, r) 
                         (mop_bef n @ tshift mp_up (2 * n), 0) stpa)",
            simp add: t_steps_ind)
      done
  qed
qed

lemma tshift_nth_state0: "\<lbrakk>n < length tp; tp ! n = (a, 0)\<rbrakk>
    \<Longrightarrow> tshift tp off ! n = (a, 0)"
apply(induct n, case_tac tp, simp)
apply(auto simp: tshift.simps)
done

lemma shift_length: "length (tshift tp n) = length tp"
apply(auto simp: tshift.simps)
done

lemma even_Suc_le: "\<lbrakk>y mod 2 = 0; 2 * x < y\<rbrakk> \<Longrightarrow> Suc (2 * x) < y"
by arith

lemma [simp]: "(4::nat) * n mod 2 = 0"
by arith

lemma tm_append_fetch_equal: 
  "\<lbrakk>t_ncorrect (tm_of aprog); s'> 0;
    fetch (mop_bef n @ tshift mp_up (2 * n)) s' b = (a, 0)\<rbrakk>
\<Longrightarrow> fetch (tm_of aprog @ tshift (mop_bef n @ tshift mp_up (2 * n)) 
    (length (tm_of aprog) div 2)) (s' + length (tm_of aprog) div 2) b 
   = (a, 0)"
apply(case_tac s', simp)
apply(auto simp: fetch.simps nth_of.simps t_ncorrect.simps shift_length nth_append
                 tshift.simps split: list.splits block.splits split: if_splits)
done

lemma [simp]:
  "\<lbrakk>t_ncorrect (tm_of aprog);
    t_step (s', l', r') (mop_bef n @ tshift mp_up (2 * n), 0) = 
                                               (0, l'', r''); s' > 0\<rbrakk>
  \<Longrightarrow> t_step (s' + length (tm_of aprog) div 2, l', r') 
        (tm_of aprog @ tshift (mop_bef n @ tshift mp_up (2 * n))
           (length (tm_of aprog) div 2), 0) = (0, l'', r'')"
apply(simp add: t_step.simps)
apply(subgoal_tac 
   "(fetch (mop_bef n @ tshift mp_up (2 * n)) s' 
              (case r' of [] \<Rightarrow> Bk | Bk # xs \<Rightarrow> Bk | Oc # xs \<Rightarrow> Oc))
  = (fetch (tm_of aprog @ tshift (mop_bef n @ tshift mp_up (2 * n)) 
       (length (tm_of aprog) div 2)) (s' + length (tm_of aprog) div 2)
    (case r' of [] \<Rightarrow> Bk | Bk # xs \<Rightarrow> Bk | Oc # xs \<Rightarrow> Oc))", simp)
apply(case_tac "(fetch (mop_bef n @ tshift mp_up (2 * n)) s' 
       (case r' of [] \<Rightarrow> Bk | Bk # xs \<Rightarrow> Bk | Oc # xs \<Rightarrow> Oc))", simp)
apply(drule_tac tm_append_fetch_equal, auto)
done

lemma [intro]: 
  "start_of (layout_of aprog) (length aprog) - Suc 0 = 
                                      length (tm_of aprog) div 2"
apply(subgoal_tac  "abc2t_correct aprog")
apply(insert pre_lheq[of "concat (take (length aprog) 
       (tms_of aprog))" "length aprog" aprog], simp add: tm_of.simps)
by auto

lemma tm_append_stop_step: 
  "\<lbrakk>t_ncorrect (tm_of aprog); 
    t_ncorrect (mop_bef n @ tshift mp_up (2 * n)); n < length lm; 
   (t_steps (Suc 0, l, r) (mop_bef n @ tshift mp_up (2 * n), 0) stp) =
                         (s', l', r');
    s' \<noteq> 0;
    t_step (s', l', r') (mop_bef n @ tshift mp_up (2 * n), 0) 
                                                     = (0, l'', r'')\<rbrakk>
     \<Longrightarrow>
(t_steps ((start_of (layout_of aprog) (length aprog), l, r)) 
  (tm_of aprog @ tshift (mop_bef n @ tshift mp_up (2 * n))
   (start_of (layout_of aprog) (length aprog) - Suc 0), 0) (Suc stp))
  = (0, l'', r'')"
apply(insert tm_append_steps_equal[of "tm_of aprog" 
      "(mop_bef n @ tshift mp_up (2 * n))"
      "(start_of (layout_of aprog) (length aprog) - Suc 0)" 
      "Suc 0" l r stp], simp)
apply(subgoal_tac "(start_of (layout_of aprog) (length aprog) - Suc 0)
              = (length (tm_of aprog) div 2)", simp add: t_steps_ind)
apply(case_tac 
 "(t_steps (start_of (layout_of aprog) (length aprog), l, r) 
      (tm_of aprog @ tshift (mop_bef n @ tshift mp_up (2 * n))
           (length (tm_of aprog) div 2), 0) stp)", simp)
apply(subgoal_tac "start_of (layout_of aprog) (length aprog) > 0", 
      case_tac "start_of (layout_of aprog) (length aprog)", 
      simp, simp)
apply(rule startof_not0, auto)
done

lemma start_of_out_range: 
"as \<ge> length aprog \<Longrightarrow> 
   start_of (layout_of aprog) as = 
             start_of (layout_of aprog) (length aprog)"
apply(induct as, simp)
apply(case_tac "length aprog = Suc as", simp)
apply(simp add: start_of.simps)
done

lemma [intro]: "t_ncorrect (tm_of aprog)"
apply(simp add: tm_of.simps)
apply(insert tms_mod2[of "length aprog" aprog], 
                                simp add: t_ncorrect.simps)
done

lemma abacus_turing_eq_halt_case_pre: 
   "\<lbrakk>ly = layout_of aprog; 
     tprog = tm_of aprog; 
     crsp_l ly ac tc ires;
     n < length am;
     abc_steps_l ac aprog stp = (as, am); 
     mop_ss = start_of ly (length aprog);
     as \<ge> length aprog\<rbrakk>
     \<Longrightarrow> \<exists> stp. (\<lambda> (s, l, r). s = 0 \<and> mopup_inv (0, l, r) am n ires)
                (t_steps tc (tprog @ (tMp n (mop_ss - 1)), 0) stp)"
apply(insert steps_crsp[of ly aprog tprog ac tc ires "(as, am)" stp], auto)
apply(case_tac "(t_steps tc (tm_of aprog, 0) n')",  
      simp add: tMp.simps)
apply(subgoal_tac "t_ncorrect (mop_bef n @ tshift mp_up (2 * n))")
proof -
  fix n' a b c
  assume h1: 
    "crsp_l (layout_of aprog) ac tc ires" 
    "abc_steps_l ac aprog stp = (as, am)" 
    "length aprog \<le> as"
    "crsp_l (layout_of aprog) (as, am) (a, b, c) ires"
    "t_steps tc (tm_of aprog, 0) n' = (a, b, c)"
    "n < length am"
    "t_ncorrect (mop_bef n @ tshift mp_up (2 * n))"
  hence h2:
  "t_steps tc (tm_of aprog @ tshift (mop_bef n @ tshift mp_up (2 * n))
    (start_of (layout_of aprog) (length aprog) - Suc 0), 0) n' 
                                    = (a, b, c)" 
    apply(rule_tac tm_append_steps, simp)
    apply(simp add: crsp_l.simps, auto)
    apply(simp add: crsp_l.simps)
    apply(rule startof_not0)
    done
  from h1 have h3: 
  "\<exists>stp. (\<lambda>(s, l, r). s \<noteq> 0 \<and> ((\<lambda> (s', l', r'). s' = 0) 
           (t_step (s, l, r) (mop_bef n @ tshift mp_up (2 * n), 0))))
         (t_steps (Suc 0, b, c) 
               (mop_bef n @ tshift mp_up (2 * n), 0) stp)"
    apply(rule_tac mopup_halt_bef, auto)
    done
  from h1 and h2 and h3 show 
    "\<exists>stp. case t_steps tc (tm_of aprog @ abacus.tshift (mop_bef n @ abacus.tshift mp_up (2 * n))
    (start_of (layout_of aprog) (length aprog) - Suc 0), 0) stp of (s, ab)
    \<Rightarrow> s = 0 \<and> mopup_inv (0, ab) am n ires"
  proof(erule_tac exE, 
    case_tac "(t_steps (Suc 0, b, c) 
              (mop_bef n @ tshift mp_up (2 * n), 0) stpa)", simp,
    case_tac "(t_step (aa, ba, ca) 
              (mop_bef n @ tshift mp_up (2 * n), 0))", simp)
    fix stpa aa ba ca aaa baa caa
    assume g1: "0 < aa \<and> aaa = 0" 
      "t_steps (Suc 0, b, c) 
      (mop_bef n @ tshift mp_up (2 * n), 0) stpa = (aa, ba,ca)" 
      "t_step (aa, ba, ca) (mop_bef n @ tshift mp_up (2 * n), 0)
      = (0, baa, caa)"
    from h1 and this have g2: 
      "t_steps (start_of (layout_of aprog) (length aprog), b, c) 
         (tm_of aprog @ tshift (mop_bef n @ tshift mp_up (2 * n)) 
           (start_of (layout_of aprog) (length aprog) - Suc 0), 0) 
                (Suc stpa) = (0, baa, caa)"
      apply(rule_tac tm_append_stop_step, auto)
      done
    from h1 and h2 and g1 and this show "?thesis"
      apply(rule_tac x = "n' + Suc stpa" in exI)
      apply(simp add: t_steps_ind del: t_steps.simps)
      apply(subgoal_tac "a = start_of (layout_of aprog) 
                                          (length aprog)", simp)
      apply(insert mopup_inv_steps[of n am "Suc 0" b c ires "Suc stpa"],
            simp add: t_steps_ind)
      apply(subgoal_tac "mopup_inv (Suc 0, b, c) am n ires", simp)
      apply(rule_tac mopup_init, simp, simp)
      apply(simp add: crsp_l.simps)
      apply(erule_tac start_of_out_range)
      done
  qed
next
  show " t_ncorrect (mop_bef n @ tshift mp_up (2 * n))"
    apply(auto simp: t_ncorrect.simps tshift.simps mp_up_def)
    done   
qed

text {*
  One of the main theorems about Abacus compilation.
*}

lemma abacus_turing_eq_halt_case: 
  assumes layout: 
  -- {* There is an Abacus program @{text "aprog"} with layout @{text "ly"}: *}
  "ly = layout_of aprog"
  and complied: 
  -- {* The TM compiled from @{text "aprog"} is @{text "tprog"}: *}
  "tprog = tm_of aprog"
  and correspond: 
  -- {* TM configuration @{text "tc"} and Abacus configuration @{text "ac"}
  are in correspondence: *}
  "crsp_l ly ac tc ires"
  and halt_state: 
  -- {* @{text "as"} is a program label outside the range of @{text "aprog"}. So 
  if Abacus is in such a state, it is in halt state: *}
  "as \<ge> length aprog"
  and abc_exec: 
  -- {* Supposing after @{text "stp"} step of execution, Abacus program @{text "aprog"}
  reaches such a halt state: *}
  "abc_steps_l ac aprog stp = (as, am)"
  and rs_len: 
  -- {* @{text "n"} is a memory address in the range of Abacus memory @{text "am"}: *}
  "n < length am"
  and mopup_start:
  -- {* The startling label for mopup mahines, according to the layout and Abacus program 
   should be @{text "mop_ss"}: *}
  "mop_ss = start_of ly (length aprog)"
  shows 
  -- {* 
  After @{text "stp"} steps of execution of the TM composed of @{text "tprog"} and the mopup 
  TM @{text "(tMp n (mop_ss - 1))"} will halt and gives rise to a configuration which 
  only hold the content of memory cell @{text "n"}:
  *}
  "\<exists> stp. (\<lambda> (s, l, r). \<exists> ln rn. s = 0 \<and>  l = Bk\<^bsup>ln\<^esup> @ Bk # Bk # ires
     \<and> r = Oc\<^bsup>Suc (abc_lm_v am n)\<^esup> @ Bk\<^bsup>rn\<^esup>)
           (t_steps tc (tprog @ (tMp n (mop_ss - 1)), 0) stp)"
proof -
  from layout complied correspond halt_state abc_exec rs_len mopup_start
       and abacus_turing_eq_halt_case_pre [of ly aprog tprog ac tc ires n am stp as mop_ss]
  show "?thesis" 
    apply(simp add: mopup_inv.simps mopup_stop.simps tape_of_nat_abv)
    done
qed

lemma abc_unhalt_case_zero: 
"\<lbrakk>crsp_l (layout_of aprog) ac tc ires;
  n < length am; 
  \<forall>stp. (\<lambda>(as, am). as < length aprog) (abc_steps_l ac aprog stp)\<rbrakk>
 \<Longrightarrow> \<exists>astp bstp. 0 \<le> bstp \<and> 
          crsp_l (layout_of aprog) (abc_steps_l ac aprog astp) 
                (t_steps tc (tm_of aprog, 0) bstp) ires"
apply(rule_tac x = "Suc 0" in exI)
apply(case_tac " abc_steps_l ac aprog (Suc 0)", simp)
proof -
  fix a b
  assume "crsp_l (layout_of aprog) ac tc ires" 
         "abc_steps_l ac aprog (Suc 0) = (a, b)"
  thus "\<exists>bstp. crsp_l (layout_of aprog) (a, b) 
               (t_steps tc (tm_of aprog, 0) bstp) ires"
    apply(insert steps_crsp[of "layout_of aprog" aprog 
                  "tm_of aprog" ac tc ires "(a, b)" "Suc 0"], auto)
    done
qed

declare abc_steps_l.simps[simp del]

lemma abc_steps_ind: 
 "let (as, am) = abc_steps_l ac aprog stp in 
   abc_steps_l ac aprog (Suc stp) =
              abc_step_l (as, am) (abc_fetch as aprog) "
proof(simp)
  show "(\<lambda>(as, am). abc_steps_l ac aprog (Suc stp) = 
        abc_step_l (as, am) (abc_fetch as aprog)) 
              (abc_steps_l ac aprog stp)"
  proof(induct stp arbitrary: ac)
    fix ac
    show "(\<lambda>(as, am). abc_steps_l ac aprog (Suc 0) = 
            abc_step_l (as, am) (abc_fetch as aprog))  
                    (abc_steps_l ac aprog 0)"
      apply(case_tac "ac:: nat \<times> nat list", 
            simp add: abc_steps_l.simps)
      apply(case_tac "(abc_step_l (a, b) (abc_fetch a aprog))",
            simp add: abc_steps_l.simps)
      done
  next
    fix stp ac
    assume h1:
      "(\<And>ac. (\<lambda>(as, am). abc_steps_l ac aprog (Suc stp) =
                            abc_step_l (as, am) (abc_fetch as aprog)) 
             (abc_steps_l ac aprog stp))"
    thus 
      "(\<lambda>(as, am). abc_steps_l ac aprog (Suc (Suc stp)) =
              abc_step_l (as, am) (abc_fetch as aprog)) 
                             (abc_steps_l ac aprog (Suc stp))"
      apply(case_tac "ac::nat \<times> nat list", simp)
      apply(subgoal_tac 
           "abc_steps_l (a, b) aprog (Suc (Suc stp)) =
            abc_steps_l (abc_step_l (a, b) (abc_fetch a aprog)) 
                                              aprog (Suc stp)", simp)
      apply(case_tac "(abc_step_l (a, b) (abc_fetch a aprog))", simp)
    proof -
      fix a b aa ba
      assume h2: "abc_step_l (a, b) (abc_fetch a aprog) = (aa, ba)"
      from h1 and h2  show 
      "(\<lambda>(as, am). abc_steps_l (aa, ba) aprog (Suc stp) = 
          abc_step_l (as, am) (abc_fetch as aprog)) 
                    (abc_steps_l (a, b) aprog (Suc stp))"
	apply(insert h1[of "(aa, ba)"])
	apply(simp add: abc_steps_l.simps)
	apply(insert h2, simp)
	done
    next
      fix a b
      show 
        "abc_steps_l (a, b) aprog (Suc (Suc stp)) = 
         abc_steps_l (abc_step_l (a, b) (abc_fetch a aprog)) 
                                                   aprog (Suc stp)"
	apply(simp only: abc_steps_l.simps)
	done
    qed
  qed
qed

lemma abc_unhalt_case_induct: 
  "\<lbrakk>crsp_l (layout_of aprog) ac tc ires;
    n < length am; 
    \<forall>stp. (\<lambda>(as, am). as < length aprog) (abc_steps_l ac aprog stp); 
    stp \<le> bstp;
    crsp_l (layout_of aprog) (abc_steps_l ac aprog astp) 
                           (t_steps tc (tm_of aprog, 0) bstp) ires\<rbrakk>
 \<Longrightarrow> \<exists>astp bstp. Suc stp \<le> bstp \<and> crsp_l (layout_of aprog) 
       (abc_steps_l ac aprog astp) (t_steps tc (tm_of aprog, 0) bstp) ires"
apply(rule_tac x = "Suc astp" in exI)
apply(case_tac "abc_steps_l ac aprog astp")
proof -
  fix a b
  assume 
    "\<forall>stp. (\<lambda>(as, am). as < length aprog)  
                 (abc_steps_l ac aprog stp)" 
    "stp \<le> bstp"
    "crsp_l (layout_of aprog) (abc_steps_l ac aprog astp) 
      (t_steps tc (tm_of aprog, 0) bstp) ires" 
    "abc_steps_l ac aprog astp = (a, b)"
  thus 
 "\<exists>bstp\<ge>Suc stp. crsp_l (layout_of aprog)
       (abc_steps_l ac aprog (Suc astp)) 
   (t_steps tc (tm_of aprog, 0) bstp) ires"
    apply(insert crsp_inside[of "layout_of aprog" aprog 
      "tm_of aprog" a b "(t_steps tc (tm_of aprog, 0) bstp)" "ires"], auto)
    apply(erule_tac x = astp in allE, auto)
    apply(rule_tac x = "bstp + stpa" in exI, simp)
    apply(insert abc_steps_ind[of ac aprog "astp"], simp)
    done
qed   

lemma abc_unhalt_case: 
  "\<lbrakk>crsp_l (layout_of aprog) ac tc ires;  
    \<forall>stp. (\<lambda>(as, am). as < length aprog) (abc_steps_l ac aprog stp)\<rbrakk>
 \<Longrightarrow> (\<exists> astp bstp. bstp \<ge> stp \<and> 
         crsp_l (layout_of aprog) (abc_steps_l ac aprog astp) 
                                (t_steps tc (tm_of aprog, 0) bstp) ires)"
apply(induct stp)
apply(rule_tac abc_unhalt_case_zero, auto)
apply(rule_tac abc_unhalt_case_induct, auto)
done
  
lemma abacus_turing_eq_unhalt_case_pre: 
  "\<lbrakk>ly = layout_of aprog; 
    tprog = tm_of aprog;
    crsp_l ly ac tc ires;
    \<forall> stp. ((\<lambda> (as, am). as < length aprog)
                       (abc_steps_l ac aprog stp));
    mop_ss = start_of ly (length aprog)\<rbrakk>
  \<Longrightarrow> (\<not> (\<exists> stp. (\<lambda> (s, l, r). s = 0)
              (t_steps tc (tprog @ (tMp n (mop_ss - 1)), 0) stp)))"
  apply(auto)
proof -
  fix stp a b
  assume h1: 
    "crsp_l (layout_of aprog) ac tc ires" 
    "\<forall>stp. (\<lambda>(as, am). as < length aprog) (abc_steps_l ac aprog stp)"
    "t_steps tc (tm_of aprog @ tMp n (start_of (layout_of aprog) 
    (length aprog) - Suc 0), 0) stp = (0, a, b)"
  thus "False"
  proof(insert abc_unhalt_case[of aprog ac tc ires stp], auto, 
        case_tac "(abc_steps_l ac aprog astp)", 
        case_tac "(t_steps tc (tm_of aprog, 0) bstp)", simp)
    fix astp bstp aa ba aaa baa c
    assume h2: 
      "abc_steps_l ac aprog astp = (aa, ba)" "stp \<le> bstp"
      "t_steps tc (tm_of aprog, 0) bstp = (aaa, baa, c)" 
      "crsp_l (layout_of aprog) (aa, ba) (aaa, baa, c) ires"
    hence h3: 
      "t_steps tc (tm_of aprog @ tMp n 
       (start_of (layout_of aprog) (length aprog) - Suc 0), 0) bstp 
                    = (aaa, baa, c)"
      apply(intro tm_append_steps, auto)
      apply(simp add: crsp_l.simps, rule startof_not0)
      done
    from h2 have h4: "\<exists> diff. bstp = stp + diff"
      apply(rule_tac x = "bstp - stp" in exI, simp)
      done
    from h4 and h3 and h2  and h1 show "?thesis"
      apply(auto)
      apply(simp add: state0_ind crsp_l.simps)
      apply(subgoal_tac "start_of (layout_of aprog) aa > 0", simp)
      apply(rule startof_not0)
      done
  qed
qed

lemma abacus_turing_eq_unhalt_case:
  assumes layout: 
  -- {* There is an Abacus program @{text "aprog"} with layout @{text "ly"}: *}
  "ly = layout_of aprog"
  and compiled: 
  -- {* The TM compiled from @{text "aprog"} is @{text "tprog"}: *}
  "tprog = tm_of aprog"
  and correspond: 
  -- {* 
  TM configuration @{text "tc"} and Abacus configuration @{text "ac"}
  are in correspondence: 
  *}
  "crsp_l ly ac tc ires"
  and abc_unhalt: 
  -- {*
  If, no matter how many steps the Abacus program @{text "aprog"} executes, it
  may never reach a halt state. 
  *}
  "\<forall> stp. ((\<lambda> (as, am). as < length aprog)
                       (abc_steps_l ac aprog stp))"
  and mopup_start: "mop_ss = start_of ly (length aprog)"
  shows
  -- {*
  The the TM composed of TM @{text "tprog"} and the moupup TM may never reach a halt state as well.
  *}
  "\<not> (\<exists> stp. (\<lambda> (s, l, r). s = 0)
              (t_steps tc (tprog @ (tMp n (mop_ss - 1)), 0) stp))"
  using layout compiled correspond abc_unhalt mopup_start
  apply(rule_tac abacus_turing_eq_unhalt_case_pre, auto)
  done


definition abc_list_crsp:: "nat list \<Rightarrow> nat list \<Rightarrow> bool"
  where
  "abc_list_crsp xs ys = (\<exists> n. xs = ys @ 0\<^bsup>n\<^esup> \<or> ys = xs @ 0\<^bsup>n\<^esup>)"
lemma [intro]: "abc_list_crsp (lm @ 0\<^bsup>m\<^esup>) lm"
apply(auto simp: abc_list_crsp_def)
done

lemma abc_list_crsp_lm_v: 
  "abc_list_crsp lma lmb \<Longrightarrow> abc_lm_v lma n = abc_lm_v lmb n"
apply(auto simp: abc_list_crsp_def abc_lm_v.simps 
                 nth_append exponent_def)
done

lemma  rep_app_cons_iff: 
  "k < n \<Longrightarrow> replicate n a[k:=b] = 
          replicate k a @ b # replicate (n - k - 1) a"
apply(induct n arbitrary: k, simp)
apply(simp split:nat.splits)
done

lemma abc_list_crsp_lm_s: 
  "abc_list_crsp lma lmb \<Longrightarrow> 
      abc_list_crsp (abc_lm_s lma m n) (abc_lm_s lmb m n)"
apply(auto simp: abc_list_crsp_def abc_lm_v.simps abc_lm_s.simps)
apply(simp_all add: list_update_append, auto simp: exponent_def)
proof -
  fix na
  assume h: "m < length lmb + na" " \<not> m < length lmb"
  hence "m - length lmb < na" by simp
  hence "replicate na 0[(m- length lmb):= n] = 
           replicate (m - length lmb) 0 @ n # 
              replicate (na - (m - length lmb) - 1) 0"
    apply(erule_tac rep_app_cons_iff)
    done
  thus "\<exists>nb. replicate na 0[m - length lmb := n] =
                 replicate (m - length lmb) 0 @ n # replicate nb 0 \<or>
                 replicate (m - length lmb) 0 @ [n] =
                 replicate na 0[m - length lmb := n] @ replicate nb 0"
    apply(auto)
    done
next
  fix na
  assume h: "\<not> m < length lmb + na"
  show 
    "\<exists>nb. replicate na 0 @ replicate (m - (length lmb + na)) 0 @ [n] =
           replicate (m - length lmb) 0 @ n # replicate nb 0 \<or>
          replicate (m - length lmb) 0 @ [n] =
            replicate na 0 @
            replicate (m - (length lmb + na)) 0 @ n # replicate nb 0"
    apply(rule_tac x = 0 in exI, simp, auto)
    using h
    apply(simp add: replicate_add[THEN sym])
    done
next
  fix na
  assume h: "\<not> m < length lma" "m < length lma + na"
  hence "m - length lma < na" by simp
  hence 
    "replicate na 0[(m- length lma):= n] = replicate (m - length lma) 
                  0 @ n # replicate (na - (m - length lma) - 1) 0"
    apply(erule_tac rep_app_cons_iff)
    done
  thus "\<exists>nb. replicate (m - length lma) 0 @ [n] =
                 replicate na 0[m - length lma := n] @ replicate nb 0 
           \<or> replicate na 0[m - length lma := n] =
                 replicate (m - length lma) 0 @ n # replicate nb 0"
    apply(auto)
    done
next
  fix na
  assume "\<not> m < length lma + na"
  thus " \<exists>nb. replicate (m - length lma) 0 @ [n] =
            replicate na 0 @
            replicate (m - (length lma + na)) 0 @ n # replicate nb 0 
        \<or>   replicate na 0 @ 
               replicate (m - (length lma + na)) 0 @ [n] =
            replicate (m - length lma) 0 @ n # replicate nb 0"
    apply(rule_tac x = 0 in exI, simp, auto)
    apply(simp add: replicate_add[THEN sym])
    done
qed

lemma abc_list_crsp_step: 
  "\<lbrakk>abc_list_crsp lma lmb; abc_step_l (aa, lma) i = (a, lma'); 
    abc_step_l (aa, lmb) i = (a', lmb')\<rbrakk>
    \<Longrightarrow> a' = a \<and> abc_list_crsp lma' lmb'"
apply(case_tac i, auto simp: abc_step_l.simps 
       abc_list_crsp_lm_s abc_list_crsp_lm_v Let_def 
                       split: abc_inst.splits if_splits)
done

lemma abc_steps_red: 
  "abc_steps_l ac aprog stp = (as, am) \<Longrightarrow>
     abc_steps_l ac aprog (Suc stp) = 
           abc_step_l (as, am) (abc_fetch as aprog)"
using abc_steps_ind[of ac aprog stp]
apply(simp)
done

lemma abc_list_crsp_steps: 
  "\<lbrakk>abc_steps_l (0, lm @ 0\<^bsup>m\<^esup>) aprog stp = (a, lm'); aprog \<noteq> []\<rbrakk> 
      \<Longrightarrow> \<exists> lma. abc_steps_l (0, lm) aprog stp = (a, lma) \<and> 
                                          abc_list_crsp lm' lma"
apply(induct stp arbitrary: a lm', simp add: abc_steps_l.simps, auto)
apply(case_tac "abc_steps_l (0, lm @ 0\<^bsup>m\<^esup>) aprog stp", 
      simp add: abc_steps_ind)
proof -
  fix stp a lm' aa b
  assume ind:
    "\<And>a lm'. aa = a \<and> b = lm' \<Longrightarrow> 
     \<exists>lma. abc_steps_l (0, lm) aprog stp = (a, lma) \<and>
                                          abc_list_crsp lm' lma"
    and h: "abc_steps_l (0, lm @ 0\<^bsup>m\<^esup>) aprog (Suc stp) = (a, lm')" 
           "abc_steps_l (0, lm @ 0\<^bsup>m\<^esup>) aprog stp = (aa, b)" 
           "aprog \<noteq> []"
  hence g1: "abc_steps_l (0, lm @ 0\<^bsup>m\<^esup>) aprog (Suc stp)
          = abc_step_l (aa, b) (abc_fetch aa aprog)"
    apply(rule_tac abc_steps_red, simp)
    done
  have "\<exists>lma. abc_steps_l (0, lm) aprog stp = (aa, lma) \<and> 
              abc_list_crsp b lma"
    apply(rule_tac ind, simp)
    done
  from this obtain lma where g2: 
    "abc_steps_l (0, lm) aprog stp = (aa, lma) \<and> 
     abc_list_crsp b lma"   ..
  hence g3: "abc_steps_l (0, lm) aprog (Suc stp)
          = abc_step_l (aa, lma) (abc_fetch aa aprog)"
    apply(rule_tac abc_steps_red, simp)
    done
  show "\<exists>lma. abc_steps_l (0, lm) aprog (Suc stp) = (a, lma) \<and>  
              abc_list_crsp lm' lma"
    using g1 g2 g3 h
    apply(auto)
    apply(case_tac "abc_step_l (aa, b) (abc_fetch aa aprog)",
          case_tac "abc_step_l (aa, lma) (abc_fetch aa aprog)", simp)
    apply(rule_tac abc_list_crsp_step, auto)
    done
qed

lemma [simp]: "(case ca of [] \<Rightarrow> Bk | Bk # xs \<Rightarrow> Bk | Oc # xs \<Rightarrow> Oc) =
                (case ca of [] \<Rightarrow> Bk | x # xs \<Rightarrow> x)"
by(case_tac ca, simp_all, case_tac a, simp, simp)

lemma steps_eq: "length t mod 2 = 0 \<Longrightarrow> 
                    t_steps c (t, 0) stp = steps c t stp"
apply(induct stp)
apply(simp add: steps.simps t_steps.simps)
apply(simp add:tstep_red t_steps_ind)
apply(case_tac "steps c t stp", simp)
apply(auto simp: t_step.simps tstep.simps)
done

lemma crsp_l_start: "crsp_l ly (0, lm) (Suc 0, Bk # Bk # ires, <lm> @ Bk\<^bsup>rn\<^esup>) ires"
apply(simp add: crsp_l.simps, auto simp: start_of.simps)
done

lemma t_ncorrect_app: "\<lbrakk>t_ncorrect t1; t_ncorrect t2\<rbrakk> \<Longrightarrow> 
                                          t_ncorrect (t1 @ t2)"
apply(simp add: t_ncorrect.simps, auto)
done

lemma [simp]: 
  "(length (tm_of aprog) + 
    length (tMp n (start_of ly (length aprog) - Suc 0))) mod 2 = 0"
apply(subgoal_tac 
 "t_ncorrect (tm_of aprog @ tMp n 
             (start_of ly (length aprog) - Suc 0))")
apply(simp add: t_ncorrect.simps)
apply(rule_tac t_ncorrect_app, 
      auto simp: tMp.simps t_ncorrect.simps tshift.simps mp_up_def)
apply(subgoal_tac
       "t_ncorrect (tm_of aprog)", simp add: t_ncorrect.simps)
apply(auto)
done

lemma [simp]: "takeWhile (\<lambda>a. a = Oc) 
              (replicate rs Oc @ replicate rn Bk) = replicate rs Oc"
apply(induct rs, auto)
apply(induct rn, auto)
done

lemma abacus_turing_eq_halt': 
  "\<lbrakk>ly = layout_of aprog; 
    tprog = tm_of aprog; 
    n < length am;
    abc_steps_l (0, lm) aprog stp = (as, am); 
    mop_ss = start_of ly (length aprog);
    as \<ge> length aprog\<rbrakk>
    \<Longrightarrow> \<exists> stp m l. steps (Suc 0, Bk # Bk # ires, <lm> @ Bk\<^bsup>rn\<^esup>) 
                (tprog @ (tMp n (mop_ss - 1))) stp
                  = (0, Bk\<^bsup>m\<^esup> @ Bk # Bk # ires, Oc\<^bsup>Suc (abc_lm_v am n)\<^esup> @ Bk\<^bsup>l\<^esup>)"
apply(drule_tac tc = "(Suc 0, Bk # Bk # ires, <lm> @ Bk\<^bsup>rn\<^esup>)" in 
               abacus_turing_eq_halt_case, auto intro: crsp_l_start)
apply(subgoal_tac 
         "length (tm_of aprog @ tMp n 
                  (start_of ly (length aprog) - Suc 0)) mod 2 = 0")
apply(simp add: steps_eq)
apply(rule_tac x = stpa in exI, 
       simp add:  exponent_def, auto)
done


lemma list_length: "xs = ys \<Longrightarrow> length xs = length ys"
by simp
lemma [elim]: "tinres (Bk\<^bsup>m\<^esup>) b \<Longrightarrow> \<exists>m. b = Bk\<^bsup>m\<^esup>"
apply(auto simp: tinres_def)
apply(rule_tac x = "m-n" in exI, 
             auto simp: exponent_def replicate_add[THEN sym]) 
apply(case_tac "m < n", auto)
apply(drule_tac list_length, auto)
apply(subgoal_tac "\<exists> d. m = d + n", auto simp: replicate_add)
apply(rule_tac x = "m - n" in exI, simp)
done
lemma [intro]: "tinres [Bk] (Bk\<^bsup>k\<^esup>) "
apply(auto simp: tinres_def exponent_def)
apply(case_tac k, auto)
apply(rule_tac x = "Suc 0" in exI, simp)
done

lemma abacus_turing_eq_halt_pre: 
 "\<lbrakk>ly = layout_of aprog; 
   tprog = tm_of aprog; 
   n < length am;     
   abc_steps_l (0, lm) aprog stp = (as, am);  
   mop_ss = start_of ly (length aprog);
   as \<ge> length aprog\<rbrakk>
  \<Longrightarrow> \<exists> stp m l. steps  (Suc 0, Bk # Bk # ires, <lm> @ Bk\<^bsup>rn\<^esup>)
               (tprog @ (tMp n (mop_ss - 1))) stp
                 = (0, Bk\<^bsup>m\<^esup> @ Bk # Bk # ires, Oc\<^bsup>Suc (abc_lm_v am n)\<^esup> @ Bk\<^bsup>l\<^esup>)"
using abacus_turing_eq_halt'
apply(simp)
done


text {*
  Main theorem for the case when the original Abacus program does halt.
*}

lemma abacus_turing_eq_halt: 
  assumes layout:
  "ly = layout_of aprog"
  -- {* There is an Abacus program @{text "aprog"} with layout @{text "ly"}: *}
  and compiled: "tprog = tm_of aprog"
  -- {* The TM compiled from @{text "aprog"} is @{text "tprog"}: *}
  and halt_state: 
   -- {* @{text "as"} is a program label outside the range of @{text "aprog"}. So 
  if Abacus is in such a state, it is in halt state: *}
  "as \<ge> length aprog"
  and abc_exec: 
  -- {* Supposing after @{text "stp"} step of execution, Abacus program @{text "aprog"}
  reaches such a halt state: *}
  "abc_steps_l (0, lm) aprog stp = (as, am)"
  and rs_locate: 
   -- {* @{text "n"} is a memory address in the range of Abacus memory @{text "am"}: *}
  "n < length am"  
  and mopup_start: 
   -- {* The startling label for mopup mahines, according to the layout and Abacus program 
   should be @{text "mop_ss"}: *}
  "mop_ss = start_of ly (length aprog)"
  shows 
  -- {* 
  After @{text "stp"} steps of execution of the TM composed of @{text "tprog"} and the mopup 
  TM @{text "(tMp n (mop_ss - 1))"} will halt and gives rise to a configuration which 
  only hold the content of memory cell @{text "n"}:
  *}
  "\<exists> stp m l. steps (Suc 0, Bk # Bk # ires, <lm> @ Bk\<^bsup>rn\<^esup>) (tprog @ (tMp n (mop_ss - 1))) stp
                      = (0, Bk\<^bsup>m\<^esup> @ Bk # Bk # ires, Oc\<^bsup>Suc (abc_lm_v am n)\<^esup> @ Bk\<^bsup>l\<^esup>)"
  using layout compiled halt_state abc_exec rs_locate mopup_start
  by(rule_tac abacus_turing_eq_halt_pre, auto)

lemma abacus_turing_eq_uhalt': 
 "\<lbrakk>ly = layout_of aprog; 
   tprog = tm_of aprog; 
   \<forall> stp. ((\<lambda> (as, am). as < length aprog) 
                   (abc_steps_l (0, lm) aprog stp));
   mop_ss = start_of ly (length aprog)\<rbrakk>
  \<Longrightarrow> (\<not> (\<exists> stp. isS0 (steps (Suc 0, [Bk, Bk], <lm>) 
                      (tprog @ (tMp n (mop_ss - 1))) stp)))"
apply(drule_tac tc = "(Suc 0, [Bk, Bk], <lm>)" and n = n and ires = "[]" in 
         abacus_turing_eq_unhalt_case, auto intro: crsp_l_start)
apply(simp add: crsp_l.simps start_of.simps)
apply(erule_tac x = stp in allE, erule_tac x = stp in allE)
apply(subgoal_tac 
   "length (tm_of aprog @ tMp n 
         (start_of ly (length aprog) - Suc 0)) mod 2 = 0")
apply(simp add: steps_eq, auto simp: isS0_def)
done

text {*
  Main theorem for the case when the original Abacus program does not halt.
  *}
lemma abacus_turing_eq_uhalt:
  assumes layout: 
  -- {* There is an Abacus program @{text "aprog"} with layout @{text "ly"}: *}
  "ly = layout_of aprog"
  and compiled:
   -- {* The TM compiled from @{text "aprog"} is @{text "tprog"}: *}
  "tprog = tm_of aprog"
  and abc_unhalt:
  -- {*
  If, no matter how many steps the Abacus program @{text "aprog"} executes, it
  may never reach a halt state. 
  *}
  "\<forall> stp. ((\<lambda> (as, am). as < length aprog) 
                      (abc_steps_l (0, lm) aprog stp))"
  and mop_start: "mop_ss = start_of ly (length aprog)"
  shows 
   -- {*
  The the TM composed of TM @{text "tprog"} and the moupup TM may never reach a halt state as well.
  *}
  "\<not> (\<exists> stp. isS0 (steps (Suc 0, [Bk, Bk], <lm>) 
                    (tprog @ (tMp n (mop_ss - 1))) stp))"
  using abacus_turing_eq_uhalt'
        layout compiled abc_unhalt mop_start
  by(auto)

end