theory IntEx

imports QuotMain

begin

fun

  intrel :: "(nat \<times> nat) \<Rightarrow> (nat \<times> nat) \<Rightarrow> bool"

where

  "intrel (x, y) (u, v) = (x + v = u + y)"

quotient my_int = "nat \<times> nat" / intrel

  apply(unfold EQUIV_def)

  apply(auto simp add: mem_def expand_fun_eq)

  done

print_theorems

quotient_def (for my_int)

  ZERO::"my_int"

where

  "ZERO \<equiv> (0::nat, 0::nat)"

quotient_def (for my_int)

  ONE::"my_int"

where

  "ONE \<equiv> (1::nat, 0::nat)"

term ONE

thm ONE_def

fun

  my_plus :: "(nat \<times> nat) \<Rightarrow> (nat \<times> nat) \<Rightarrow> (nat \<times> nat)"

where

  "my_plus (x, y) (u, v) = (x + u, y + v)"

quotient_def (for my_int)

  PLUS::"my_int \<Rightarrow> my_int \<Rightarrow> my_int"

where

  "PLUS \<equiv> my_plus"

term PLUS

thm PLUS_def

fun

  my_neg :: "(nat \<times> nat) \<Rightarrow> (nat \<times> nat)"

where

  "my_neg (x, y) = (y, x)"

quotient_def (for my_int)

  NEG::"my_int \<Rightarrow> my_int"

where

  "NEG \<equiv> my_neg"

term NEG

thm NEG_def

definition

  MINUS :: "my_int \<Rightarrow> my_int \<Rightarrow> my_int"

where

  "MINUS z w = PLUS z (NEG w)"

fun

  my_mult :: "(nat \<times> nat) \<Rightarrow> (nat \<times> nat) \<Rightarrow> (nat \<times> nat)"

where

  "my_mult (x, y) (u, v) = (x*u + y*v, x*v + y*u)"

quotient_def (for my_int)

  MULT::"my_int \<Rightarrow> my_int \<Rightarrow> my_int"

where

  "MULT \<equiv> my_mult"

term MULT

thm MULT_def

(* NOT SURE WETHER THIS DEFINITION IS CORRECT *)

fun

  my_le :: "(nat \<times> nat) \<Rightarrow> (nat \<times> nat) \<Rightarrow> bool"

where

  "my_le (x, y) (u, v) = (x+v \<le> u+y)"

quotient_def (for my_int)

  LE :: "my_int \<Rightarrow> my_int \<Rightarrow> bool"

where

  "LE \<equiv> my_le"

term LE

thm LE_def

definition

  LESS :: "my_int \<Rightarrow> my_int \<Rightarrow> bool"

where

  "LESS z w = (LE z w \<and> z \<noteq> w)"

term LESS

thm LESS_def

definition

  ABS :: "my_int \<Rightarrow> my_int"

where

  "ABS i = (if (LESS i ZERO) then (NEG i) else i)"

definition

  SIGN :: "my_int \<Rightarrow> my_int"

where

 "SIGN i = (if i = ZERO then ZERO else if (LESS ZERO i) then ONE else (NEG ONE))"

lemma plus_sym_pre:

  shows "intrel (my_plus a b) (my_plus b a)"

  apply(cases a)

  apply(cases b)

  apply(auto)

  done

lemma ho_plus_rsp:

  "(intrel ===> intrel ===> intrel) my_plus my_plus"

  by (simp)

ML {* val qty = @{typ "my_int"} *}

ML {* val ty_name = "my_int" *}

ML {* val rsp_thms = @{thms ho_plus_rsp} @ @{thms ho_all_prs ho_ex_prs} *}

ML {* val t_defs = @{thms PLUS_def} *}

ML {*

fun lift_thm_my_int lthy t =

  lift_thm lthy qty ty_name rsp_thms t_defs t

*}

ML {*

  val (rty, rel, rel_refl, rel_eqv) = lookup_quot_data @{context} qty;

*}

ML {* lift_thm_my_int @{context} @{thm plus_sym_pre} *}

lemma plus_assoc_pre:

  shows "intrel (my_plus (my_plus i j) k) (my_plus i (my_plus j k))"

  apply (cases i)

  apply (cases j)

  apply (cases k)

  apply (simp)

  done

ML {* lift_thm_my_int @{context} @{thm plus_assoc_pre} *}

text {* Below is the construction site code used if things do not work *}

ML {* val abs = findabs rty (prop_of (atomize_thm @{thm plus_sym_pre})) *}

ML {* val simp_lam_prs_thms = map (make_simp_lam_prs_thm @{context} quot) abs *}

ML {* val t_defs_sym = add_lower_defs @{context} t_defs *}

ML {* val t_a = atomize_thm @{thm plus_sym_pre} *}

ML {* val t_r = regularize t_a rty rel rel_eqv @{context} *}

ML {* val t_t = repabs @{context} t_r consts rty qty quot rel_refl trans2 rsp_thms *}

ML {* val t_l = repeat_eqsubst_thm @{context} simp_lam_prs_thms t_t *}

ML {* val t_a = simp_allex_prs @{context} quot t_l *}

ML {* val t_d = repeat_eqsubst_thm @{context} t_defs_sym t_a *}

ML {* val t_r = MetaSimplifier.rewrite_rule [reps_same] t_d *}

ML {* ObjectLogic.rulify t_r *}