prio/Prio.thy
changeset 282 a3b4eed091d2
parent 281 e5bfdd2d1ac8
child 283 7d2bab099b89
--- a/prio/Prio.thy	Sun Feb 05 14:29:08 2012 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,2813 +0,0 @@
-theory Prio
-imports Precedence_ord Moment Lsp Happen_within
-begin
-
-type_synonym thread = nat
-type_synonym priority = nat
-type_synonym cs = nat
-
-datatype event = 
-  Create thread priority |
-  Exit thread |
-  P thread cs |
-  V thread cs |
-  Set thread priority
-
-datatype node = 
-   Th "thread" |
-   Cs "cs"
-
-type_synonym state = "event list"
-
-fun threads :: "state \<Rightarrow> thread set"
-where 
-  "threads [] = {}" |
-  "threads (Create thread prio#s) = {thread} \<union> threads s" |
-  "threads (Exit thread # s) = (threads s) - {thread}" |
-  "threads (e#s) = threads s"
-
-fun original_priority :: "thread \<Rightarrow> state \<Rightarrow> nat"
-where
-  "original_priority thread [] = 0" |
-  "original_priority thread (Create thread' prio#s) = 
-     (if thread' = thread then prio else original_priority thread s)" |
-  "original_priority thread (Set thread' prio#s) = 
-     (if thread' = thread then prio else original_priority thread s)" |
-  "original_priority thread (e#s) = original_priority thread s"
-
-fun birthtime :: "thread \<Rightarrow> state \<Rightarrow> nat"
-where
-  "birthtime thread [] = 0" |
-  "birthtime thread ((Create thread' prio)#s) = (if (thread = thread') then length s 
-                                                  else birthtime thread s)" |
-  "birthtime thread ((Set thread' prio)#s) = (if (thread = thread') then length s 
-                                                  else birthtime thread s)" |
-  "birthtime thread (e#s) = birthtime thread s"
-
-definition preced :: "thread \<Rightarrow> state \<Rightarrow> precedence"
-  where "preced thread s = Prc (original_priority thread s) (birthtime thread s)"
-
-consts holding :: "'b \<Rightarrow> thread \<Rightarrow> cs \<Rightarrow> bool"
-       waiting :: "'b \<Rightarrow> thread \<Rightarrow> cs \<Rightarrow> bool"
-       depend :: "'b \<Rightarrow> (node \<times> node) set"
-       dependents :: "'b \<Rightarrow> thread \<Rightarrow> thread set"
-
-defs (overloaded) cs_holding_def: "holding wq thread cs == (thread \<in> set (wq cs) \<and> thread = hd (wq cs))"
-                  cs_waiting_def: "waiting wq thread cs == (thread \<in> set (wq cs) \<and> thread \<noteq> hd (wq cs))"
-                  cs_depend_def: "depend (wq::cs \<Rightarrow> thread list) == {(Th t, Cs c) | t c. waiting wq t c} \<union> 
-                                               {(Cs c, Th t) | c t. holding wq t c}"
-                  cs_dependents_def: "dependents (wq::cs \<Rightarrow> thread list) th == {th' . (Th th', Th th) \<in> (depend wq)^+}"
-
-record schedule_state = 
-    waiting_queue :: "cs \<Rightarrow> thread list"
-    cur_preced :: "thread \<Rightarrow> precedence"
-
-
-definition cpreced :: "state \<Rightarrow> (cs \<Rightarrow> thread list) \<Rightarrow> thread \<Rightarrow> precedence"
-where "cpreced s wq = (\<lambda> th. Max ((\<lambda> th. preced th s) ` ({th} \<union> dependents wq th)))"
-
-fun schs :: "state \<Rightarrow> schedule_state"
-where
-   "schs [] = \<lparr>waiting_queue = \<lambda> cs. [], 
-               cur_preced = cpreced [] (\<lambda> cs. [])\<rparr>" |
-   "schs (e#s) = (let ps = schs s in
-                  let pwq = waiting_queue ps in
-                  let pcp = cur_preced ps in
-                  let nwq = case e of
-                             P thread cs \<Rightarrow>  pwq(cs:=(pwq cs @ [thread])) |
-                             V thread cs \<Rightarrow> let nq = case (pwq cs) of
-                                                      [] \<Rightarrow> [] | 
-                                                      (th#pq) \<Rightarrow> case (lsp pcp pq) of
-                                                                   (l, [], r) \<Rightarrow> []
-                                                                 | (l, m#ms, r) \<Rightarrow> m#(l@ms@r)
-                                            in pwq(cs:=nq)                 |
-                              _ \<Rightarrow> pwq
-                  in let ncp = cpreced (e#s) nwq in 
-                     \<lparr>waiting_queue = nwq, cur_preced = ncp\<rparr>
-                 )"
-
-definition wq :: "state \<Rightarrow> cs \<Rightarrow> thread list" 
-where "wq s == waiting_queue (schs s)"
-
-definition cp :: "state \<Rightarrow> thread \<Rightarrow> precedence"
-where "cp s = cur_preced (schs s)"
-
-defs (overloaded) s_holding_def: "holding (s::state) thread cs == (thread \<in> set (wq s cs) \<and> thread = hd (wq s cs))"
-                  s_waiting_def: "waiting (s::state) thread cs == (thread \<in> set (wq s cs) \<and> thread \<noteq> hd (wq s cs))"
-                  s_depend_def: "depend (s::state) == {(Th t, Cs c) | t c. waiting (wq s) t c} \<union> 
-                                               {(Cs c, Th t) | c t. holding (wq s) t c}"
-                  s_dependents_def: "dependents (s::state) th == {th' . (Th th', Th th) \<in> (depend (wq s))^+}"
-
-definition readys :: "state \<Rightarrow> thread set"
-where
-  "readys s = 
-     {thread . thread \<in> threads s \<and> (\<forall> cs. \<not> waiting s thread cs)}"
-
-definition runing :: "state \<Rightarrow> thread set"
-where "runing s = {th . th \<in> readys s \<and> cp s th = Max ((cp s) ` (readys s))}"
-
-definition holdents :: "state \<Rightarrow> thread \<Rightarrow> cs set"
-  where "holdents s th = {cs . (Cs cs, Th th) \<in> depend s}"
-
-inductive step :: "state \<Rightarrow> event \<Rightarrow> bool"
-where
-  thread_create: "\<lbrakk>prio \<le> max_prio; thread \<notin> threads s\<rbrakk> \<Longrightarrow> step s (Create thread prio)" |
-  thread_exit: "\<lbrakk>thread \<in> runing s; holdents s thread = {}\<rbrakk> \<Longrightarrow> step s (Exit thread)" |
-  thread_P: "\<lbrakk>thread \<in> runing s;  (Cs cs, Th thread)  \<notin> (depend s)^+\<rbrakk> \<Longrightarrow> step s (P thread cs)" |
-  thread_V: "\<lbrakk>thread \<in> runing s;  holding s thread cs\<rbrakk> \<Longrightarrow> step s (V thread cs)" |
-  thread_set: "\<lbrakk>thread \<in> runing s\<rbrakk> \<Longrightarrow> step s (Set thread prio)"
-
-inductive vt :: "(state \<Rightarrow> event \<Rightarrow> bool) \<Rightarrow> state \<Rightarrow> bool"
- for cs
-where
-  vt_nil[intro]: "vt cs []" |
-  vt_cons[intro]: "\<lbrakk>vt cs s; cs s e\<rbrakk> \<Longrightarrow> vt cs (e#s)"
-
-lemma runing_ready: "runing s \<subseteq> readys s"
-  by (auto simp only:runing_def readys_def)
-
-lemma wq_v_eq_nil: 
-  fixes s cs thread rest
-  assumes eq_wq: "wq s cs = thread # rest"
-  and eq_lsp: "lsp (cp s) rest = (l, [], r)"
-  shows "wq (V thread cs#s) cs = []"
-proof -
-  from prems show ?thesis
-    by (auto simp:wq_def Let_def cp_def split:list.splits)
-qed
-
-lemma wq_v_eq: 
-  fixes s cs thread rest
-  assumes eq_wq: "wq s cs = thread # rest"
-  and eq_lsp: "lsp (cp s) rest = (l, [th'], r)"
-  shows "wq (V thread cs#s) cs = th'#l@r"
-proof -
-  from prems show ?thesis
-    by (auto simp:wq_def Let_def cp_def split:list.splits)
-qed
-
-lemma wq_v_neq:
-   "cs \<noteq> cs' \<Longrightarrow> wq (V thread cs#s) cs' = wq s cs'"
-  by (auto simp:wq_def Let_def cp_def split:list.splits)
-
-lemma wq_distinct: "vt step s \<Longrightarrow> distinct (wq s cs)"
-proof(erule_tac vt.induct, simp add:wq_def)
-  fix s e
-  assume h1: "step s e"
-  and h2: "distinct (wq s cs)"
-  thus "distinct (wq (e # s) cs)"
-  proof(induct rule:step.induct, auto simp: wq_def Let_def split:list.splits)
-    fix thread s
-    assume h1: "(Cs cs, Th thread) \<notin> (depend s)\<^sup>+"
-      and h2: "thread \<in> set (waiting_queue (schs s) cs)"
-      and h3: "thread \<in> runing s"
-    show "False" 
-    proof -
-      from h3 have "\<And> cs. thread \<in>  set (waiting_queue (schs s) cs) \<Longrightarrow> 
-                             thread = hd ((waiting_queue (schs s) cs))" 
-        by (simp add:runing_def readys_def s_waiting_def wq_def)
-      from this [OF h2] have "thread = hd (waiting_queue (schs s) cs)" .
-      with h2
-      have "(Cs cs, Th thread) \<in> (depend s)"
-        by (simp add:s_depend_def s_holding_def wq_def cs_holding_def)
-      with h1 show False by auto
-    qed
-  next
-    fix thread s a list
-    assume h1: "thread \<in> runing s" 
-      and h2: "holding s thread cs"
-      and h3: "waiting_queue (schs s) cs = a # list"
-      and h4: "a \<notin> set list"
-      and h5: "distinct list"
-    thus "distinct
-           ((\<lambda>(l, a, r). case a of [] \<Rightarrow> [] | m # ms \<Rightarrow> m # l @ ms @ r)
-             (lsp (cur_preced (schs s)) list))"
-    apply (cases "(lsp (cur_preced (schs s)) list)", simp)
-    apply (case_tac b, simp)
-    by (drule_tac lsp_set_eq, simp)
-  qed
-qed
-
-lemma block_pre: 
-  fixes thread cs s
-  assumes s_ni: "thread \<notin>  set (wq s cs)"
-  and s_i: "thread \<in> set (wq (e#s) cs)"
-  shows "e = P thread cs"
-proof -
-  have ee: "\<And> x y. \<lbrakk>x = y\<rbrakk> \<Longrightarrow> set x = set y"
-    by auto
-  from s_ni s_i show ?thesis
-  proof (cases e, auto split:if_splits simp add:Let_def wq_def)
-    fix uu uub uuc uud uue
-    assume h: "(uuc, thread # uu, uub) = lsp (cur_preced (schs s)) uud"
-      and h1 [symmetric]: "uue # uud = waiting_queue (schs s) cs"
-      and h2: "thread \<notin> set (waiting_queue (schs s) cs)"
-    from lsp_set [OF h] have "set (uuc @ (thread # uu) @ uub) = set uud" .
-    hence "thread \<in> set uud" by auto
-    with h1 have "thread \<in> set (waiting_queue (schs s) cs)" by auto
-    with h2 show False by auto
-  next
-    fix uu uua uub uuc uud uue
-    assume h1: "thread \<notin> set (waiting_queue (schs s) cs)"
-      and h2: "uue # uud = waiting_queue (schs s) cs"
-      and h3: "(uuc, uua # uu, uub) = lsp (cur_preced (schs s)) uud"
-      and h4: "thread \<in> set uuc"
-    from lsp_set [OF h3] have "set (uuc @ (uua # uu) @ uub) = set uud" .
-    with h4 have "thread \<in> set uud" by auto
-    with h2 have "thread \<in> set (waiting_queue (schs s) cs)" 
-      apply (drule_tac ee) by auto
-    with h1 show "False" by fast
-  next
-    fix uu uua uub uuc uud uue
-    assume h1: "thread \<notin> set (waiting_queue (schs s) cs)"
-      and h2: "uue # uud = waiting_queue (schs s) cs"
-      and h3: "(uuc, uua # uu, uub) = lsp (cur_preced (schs s)) uud"
-      and h4: "thread \<in> set uu"
-    from lsp_set [OF h3] have "set (uuc @ (uua # uu) @ uub) = set uud" .
-    with h4 have "thread \<in> set uud" by auto
-    with h2 have "thread \<in> set (waiting_queue (schs s) cs)" 
-      apply (drule_tac ee) by auto
-    with h1 show "False" by fast
-  next
-    fix uu uua uub uuc uud uue
-    assume h1: "thread \<notin> set (waiting_queue (schs s) cs)"
-      and h2: "uue # uud = waiting_queue (schs s) cs"
-      and h3: "(uuc, uua # uu, uub) = lsp (cur_preced (schs s)) uud"
-      and h4: "thread \<in> set uub"
-    from lsp_set [OF h3] have "set (uuc @ (uua # uu) @ uub) = set uud" .
-    with h4 have "thread \<in> set uud" by auto
-    with h2 have "thread \<in> set (waiting_queue (schs s) cs)" 
-      apply (drule_tac ee) by auto
-    with h1 show "False" by fast
-  qed
-qed
-
-lemma p_pre: "\<lbrakk>vt step ((P thread cs)#s)\<rbrakk> \<Longrightarrow> 
-  thread \<in> runing s \<and> (Cs cs, Th thread)  \<notin> (depend s)^+"
-apply (ind_cases "vt step ((P thread cs)#s)")
-apply (ind_cases "step s (P thread cs)")
-by auto
-
-lemma abs1:
-  fixes e es
-  assumes ein: "e \<in> set es"
-  and neq: "hd es \<noteq> hd (es @ [x])"
-  shows "False"
-proof -
-  from ein have "es \<noteq> []" by auto
-  then obtain e ess where "es = e # ess" by (cases es, auto)
-  with neq show ?thesis by auto
-qed
-
-lemma q_head: "Q (hd es) \<Longrightarrow> hd es = hd [th\<leftarrow>es . Q th]"
-  by (cases es, auto)
-
-inductive_cases evt_cons: "vt cs (a#s)"
-
-lemma abs2:
-  assumes vt: "vt step (e#s)"
-  and inq: "thread \<in> set (wq s cs)"
-  and nh: "thread = hd (wq s cs)"
-  and qt: "thread \<noteq> hd (wq (e#s) cs)"
-  and inq': "thread \<in> set (wq (e#s) cs)"
-  shows "False"
-proof -
-  have ee: "\<And> uuc thread uu uub s list. (uuc, thread # uu, uub) = lsp (cur_preced (schs s)) list \<Longrightarrow> 
-                 lsp (cur_preced (schs s)) list = (uuc, thread # uu, uub) 
-               " by simp
-  from prems show "False"
-    apply (cases e)
-    apply ((simp split:if_splits add:Let_def wq_def)[1])+
-    apply (insert abs1, fast)[1] 
-    apply ((simp split:if_splits add:Let_def)[1])+
-    apply (simp split:if_splits list.splits add:Let_def wq_def) 
-    apply (auto dest!:ee)
-    apply (drule_tac lsp_set_eq, simp)
-    apply (subgoal_tac "distinct (waiting_queue (schs s) cs)", simp, fold wq_def)
-    apply (rule_tac wq_distinct, auto)
-    apply (erule_tac evt_cons, auto)
-    apply (drule_tac lsp_set_eq, simp)
-    apply (subgoal_tac "distinct (wq s cs)", simp)
-    apply (rule_tac wq_distinct, auto)
-    apply (erule_tac evt_cons, auto)
-    apply (drule_tac lsp_set_eq, simp)
-    apply (subgoal_tac "distinct (wq s cs)", simp)
-    apply (rule_tac wq_distinct, auto)
-    apply (erule_tac evt_cons, auto)
-    apply (auto simp:wq_def Let_def split:if_splits prod.splits)
-    done
-qed
-
-lemma vt_moment: "\<And> t. \<lbrakk>vt cs s; t \<le> length s\<rbrakk> \<Longrightarrow> vt cs (moment t s)"
-proof(induct s, simp)
-  fix a s t
-  assume h: "\<And>t.\<lbrakk>vt cs s; t \<le> length s\<rbrakk> \<Longrightarrow> vt cs (moment t s)"
-    and vt_a: "vt cs (a # s)"
-    and le_t: "t \<le> length (a # s)"
-  show "vt cs (moment t (a # s))"
-  proof(cases "t = length (a#s)")
-    case True
-    from True have "moment t (a#s) = a#s" by simp
-    with vt_a show ?thesis by simp
-  next
-    case False
-    with le_t have le_t1: "t \<le> length s" by simp
-    from vt_a have "vt cs s"
-      by (erule_tac evt_cons, simp)
-    from h [OF this le_t1] have "vt cs (moment t s)" .
-    moreover have "moment t (a#s) = moment t s"
-    proof -
-      from moment_app [OF le_t1, of "[a]"] 
-      show ?thesis by simp
-    qed
-    ultimately show ?thesis by auto
-  qed
-qed
-
-(* Wrong:
-    lemma \<lbrakk>thread \<in> set (waiting_queue cs1 s); thread \<in> set (waiting_queue cs2 s)\<rbrakk> \<Longrightarrow> cs1 = cs2"
-*)
-
-lemma waiting_unique_pre:
-  fixes cs1 cs2 s thread
-  assumes vt: "vt step s"
-  and h11: "thread \<in> set (wq s cs1)"
-  and h12: "thread \<noteq> hd (wq s cs1)"
-  assumes h21: "thread \<in> set (wq s cs2)"
-  and h22: "thread \<noteq> hd (wq s cs2)"
-  and neq12: "cs1 \<noteq> cs2"
-  shows "False"
-proof -
-  let "?Q cs s" = "thread \<in> set (wq s cs) \<and> thread \<noteq> hd (wq s cs)"
-  from h11 and h12 have q1: "?Q cs1 s" by simp
-  from h21 and h22 have q2: "?Q cs2 s" by simp
-  have nq1: "\<not> ?Q cs1 []" by (simp add:wq_def)
-  have nq2: "\<not> ?Q cs2 []" by (simp add:wq_def)
-  from p_split [of "?Q cs1", OF q1 nq1]
-  obtain t1 where lt1: "t1 < length s"
-    and np1: "\<not>(thread \<in> set (wq (moment t1 s) cs1) \<and>
-        thread \<noteq> hd (wq (moment t1 s) cs1))"
-    and nn1: "(\<forall>i'>t1. thread \<in> set (wq (moment i' s) cs1) \<and>
-             thread \<noteq> hd (wq (moment i' s) cs1))" by auto
-  from p_split [of "?Q cs2", OF q2 nq2]
-  obtain t2 where lt2: "t2 < length s"
-    and np2: "\<not>(thread \<in> set (wq (moment t2 s) cs2) \<and>
-        thread \<noteq> hd (wq (moment t2 s) cs2))"
-    and nn2: "(\<forall>i'>t2. thread \<in> set (wq (moment i' s) cs2) \<and>
-             thread \<noteq> hd (wq (moment i' s) cs2))" by auto
-  show ?thesis
-  proof -
-    { 
-      assume lt12: "t1 < t2"
-      let ?t3 = "Suc t2"
-      from lt2 have le_t3: "?t3 \<le> length s" by auto
-      from moment_plus [OF this] 
-      obtain e where eq_m: "moment ?t3 s = e#moment t2 s" by auto
-      have "t2 < ?t3" by simp
-      from nn2 [rule_format, OF this] and eq_m
-      have h1: "thread \<in> set (wq (e#moment t2 s) cs2)" and
-        h2: "thread \<noteq> hd (wq (e#moment t2 s) cs2)" by auto
-      have vt_e: "vt step (e#moment t2 s)"
-      proof -
-        from vt_moment [OF vt le_t3]
-        have "vt step (moment ?t3 s)" .
-        with eq_m show ?thesis by simp
-      qed
-      have ?thesis
-      proof(cases "thread \<in> set (wq (moment t2 s) cs2)")
-        case True
-        from True and np2 have eq_th: "thread = hd (wq (moment t2 s) cs2)"
-          by auto
-        from abs2 [OF vt_e True eq_th h2 h1]
-        show ?thesis by auto
-      next
-        case False
-        from block_pre [OF False h1]
-        have "e = P thread cs2" .
-        with vt_e have "vt step ((P thread cs2)# moment t2 s)" by simp
-        from p_pre [OF this] have "thread \<in> runing (moment t2 s)" by simp
-        with runing_ready have "thread \<in> readys (moment t2 s)" by auto
-        with nn1 [rule_format, OF lt12]
-        show ?thesis  by (simp add:readys_def s_waiting_def, auto)
-      qed
-    } moreover {
-      assume lt12: "t2 < t1"
-      let ?t3 = "Suc t1"
-      from lt1 have le_t3: "?t3 \<le> length s" by auto
-      from moment_plus [OF this] 
-      obtain e where eq_m: "moment ?t3 s = e#moment t1 s" by auto
-      have lt_t3: "t1 < ?t3" by simp
-      from nn1 [rule_format, OF this] and eq_m
-      have h1: "thread \<in> set (wq (e#moment t1 s) cs1)" and
-        h2: "thread \<noteq> hd (wq (e#moment t1 s) cs1)" by auto
-      have vt_e: "vt step (e#moment t1 s)"
-      proof -
-        from vt_moment [OF vt le_t3]
-        have "vt step (moment ?t3 s)" .
-        with eq_m show ?thesis by simp
-      qed
-      have ?thesis
-      proof(cases "thread \<in> set (wq (moment t1 s) cs1)")
-        case True
-        from True and np1 have eq_th: "thread = hd (wq (moment t1 s) cs1)"
-          by auto
-        from abs2 [OF vt_e True eq_th h2 h1]
-        show ?thesis by auto
-      next
-        case False
-        from block_pre [OF False h1]
-        have "e = P thread cs1" .
-        with vt_e have "vt step ((P thread cs1)# moment t1 s)" by simp
-        from p_pre [OF this] have "thread \<in> runing (moment t1 s)" by simp
-        with runing_ready have "thread \<in> readys (moment t1 s)" by auto
-        with nn2 [rule_format, OF lt12]
-        show ?thesis  by (simp add:readys_def s_waiting_def, auto)
-      qed
-    } moreover {
-      assume eqt12: "t1 = t2"
-      let ?t3 = "Suc t1"
-      from lt1 have le_t3: "?t3 \<le> length s" by auto
-      from moment_plus [OF this] 
-      obtain e where eq_m: "moment ?t3 s = e#moment t1 s" by auto
-      have lt_t3: "t1 < ?t3" by simp
-      from nn1 [rule_format, OF this] and eq_m
-      have h1: "thread \<in> set (wq (e#moment t1 s) cs1)" and
-        h2: "thread \<noteq> hd (wq (e#moment t1 s) cs1)" by auto
-      have vt_e: "vt step (e#moment t1 s)"
-      proof -
-        from vt_moment [OF vt le_t3]
-        have "vt step (moment ?t3 s)" .
-        with eq_m show ?thesis by simp
-      qed
-      have ?thesis
-      proof(cases "thread \<in> set (wq (moment t1 s) cs1)")
-        case True
-        from True and np1 have eq_th: "thread = hd (wq (moment t1 s) cs1)"
-          by auto
-        from abs2 [OF vt_e True eq_th h2 h1]
-        show ?thesis by auto
-      next
-        case False
-        from block_pre [OF False h1]
-        have eq_e1: "e = P thread cs1" .
-        have lt_t3: "t1 < ?t3" by simp
-        with eqt12 have "t2 < ?t3" by simp
-        from nn2 [rule_format, OF this] and eq_m and eqt12
-        have h1: "thread \<in> set (wq (e#moment t2 s) cs2)" and
-          h2: "thread \<noteq> hd (wq (e#moment t2 s) cs2)" by auto
-        show ?thesis
-        proof(cases "thread \<in> set (wq (moment t2 s) cs2)")
-          case True
-          from True and np2 have eq_th: "thread = hd (wq (moment t2 s) cs2)"
-            by auto
-          from vt_e and eqt12 have "vt step (e#moment t2 s)" by simp 
-          from abs2 [OF this True eq_th h2 h1]
-          show ?thesis .
-        next
-          case False
-          from block_pre [OF False h1]
-          have "e = P thread cs2" .
-          with eq_e1 neq12 show ?thesis by auto
-        qed
-      qed
-    } ultimately show ?thesis by arith
-  qed
-qed
-
-lemma waiting_unique:
-  assumes "vt step s"
-  and "waiting s th cs1"
-  and "waiting s th cs2"
-  shows "cs1 = cs2"
-proof -
-  from waiting_unique_pre and prems
-  show ?thesis
-    by (auto simp add:s_waiting_def)
-qed
-
-lemma holded_unique:
-  assumes "vt step s"
-  and "holding s th1 cs"
-  and "holding s th2 cs"
-  shows "th1 = th2"
-proof -
-  from prems show ?thesis
-    unfolding s_holding_def
-    by auto
-qed
-
-lemma birthtime_lt: "th \<in> threads s \<Longrightarrow> birthtime th s < length s"
-  apply (induct s, auto)
-  by (case_tac a, auto split:if_splits)
-
-lemma birthtime_unique: 
-  "\<lbrakk>birthtime th1 s = birthtime th2 s; th1 \<in> threads s; th2 \<in> threads s\<rbrakk>
-          \<Longrightarrow> th1 = th2"
-  apply (induct s, auto)
-  by (case_tac a, auto split:if_splits dest:birthtime_lt)
-
-lemma preced_unique : 
-  assumes pcd_eq: "preced th1 s = preced th2 s"
-  and th_in1: "th1 \<in> threads s"
-  and th_in2: " th2 \<in> threads s"
-  shows "th1 = th2"
-proof -
-  from pcd_eq have "birthtime th1 s = birthtime th2 s" by (simp add:preced_def)
-  from birthtime_unique [OF this th_in1 th_in2]
-  show ?thesis .
-qed
-
-lemma preced_linorder: 
-  assumes neq_12: "th1 \<noteq> th2"
-  and th_in1: "th1 \<in> threads s"
-  and th_in2: " th2 \<in> threads s"
-  shows "preced th1 s < preced th2 s \<or> preced th1 s > preced th2 s"
-proof -
-  from preced_unique [OF _ th_in1 th_in2] and neq_12 
-  have "preced th1 s \<noteq> preced th2 s" by auto
-  thus ?thesis by auto
-qed
-
-lemma unique_minus:
-  fixes x y z r
-  assumes unique: "\<And> a b c. \<lbrakk>(a, b) \<in> r; (a, c) \<in> r\<rbrakk> \<Longrightarrow> b = c"
-  and xy: "(x, y) \<in> r"
-  and xz: "(x, z) \<in> r^+"
-  and neq: "y \<noteq> z"
-  shows "(y, z) \<in> r^+"
-proof -
- from xz and neq show ?thesis
- proof(induct)
-   case (base ya)
-   have "(x, ya) \<in> r" by fact
-   from unique [OF xy this] have "y = ya" .
-   with base show ?case by auto
- next
-   case (step ya z)
-   show ?case
-   proof(cases "y = ya")
-     case True
-     from step True show ?thesis by simp
-   next
-     case False
-     from step False
-     show ?thesis by auto
-   qed
- qed
-qed
-
-lemma unique_base:
-  fixes r x y z
-  assumes unique: "\<And> a b c. \<lbrakk>(a, b) \<in> r; (a, c) \<in> r\<rbrakk> \<Longrightarrow> b = c"
-  and xy: "(x, y) \<in> r"
-  and xz: "(x, z) \<in> r^+"
-  and neq_yz: "y \<noteq> z"
-  shows "(y, z) \<in> r^+"
-proof -
-  from xz neq_yz show ?thesis
-  proof(induct)
-    case (base ya)
-    from xy unique base show ?case by auto
-  next
-    case (step ya z)
-    show ?case
-    proof(cases "y = ya")
-      case True
-      from True step show ?thesis by auto
-    next
-      case False
-      from False step 
-      have "(y, ya) \<in> r\<^sup>+" by auto
-      with step show ?thesis by auto
-    qed
-  qed
-qed
-
-lemma unique_chain:
-  fixes r x y z
-  assumes unique: "\<And> a b c. \<lbrakk>(a, b) \<in> r; (a, c) \<in> r\<rbrakk> \<Longrightarrow> b = c"
-  and xy: "(x, y) \<in> r^+"
-  and xz: "(x, z) \<in> r^+"
-  and neq_yz: "y \<noteq> z"
-  shows "(y, z) \<in> r^+ \<or> (z, y) \<in> r^+"
-proof -
-  from xy xz neq_yz show ?thesis
-  proof(induct)
-    case (base y)
-    have h1: "(x, y) \<in> r" and h2: "(x, z) \<in> r\<^sup>+" and h3: "y \<noteq> z" using base by auto
-    from unique_base [OF _ h1 h2 h3] and unique show ?case by auto
-  next
-    case (step y za)
-    show ?case
-    proof(cases "y = z")
-      case True
-      from True step show ?thesis by auto
-    next
-      case False
-      from False step have "(y, z) \<in> r\<^sup>+ \<or> (z, y) \<in> r\<^sup>+" by auto
-      thus ?thesis
-      proof
-        assume "(z, y) \<in> r\<^sup>+"
-        with step have "(z, za) \<in> r\<^sup>+" by auto
-        thus ?thesis by auto
-      next
-        assume h: "(y, z) \<in> r\<^sup>+"
-        from step have yza: "(y, za) \<in> r" by simp
-        from step have "za \<noteq> z" by simp
-        from unique_minus [OF _ yza h this] and unique
-        have "(za, z) \<in> r\<^sup>+" by auto
-        thus ?thesis by auto
-      qed
-    qed
-  qed
-qed
-
-lemma depend_set_unchanged: "(depend (Set th prio # s)) = depend s"
-apply (unfold s_depend_def s_waiting_def wq_def)
-by (simp add:Let_def)
-
-lemma depend_create_unchanged: "(depend (Create th prio # s)) = depend s"
-apply (unfold s_depend_def s_waiting_def wq_def)
-by (simp add:Let_def)
-
-lemma depend_exit_unchanged: "(depend (Exit th # s)) = depend s"
-apply (unfold s_depend_def s_waiting_def wq_def)
-by (simp add:Let_def)
-
-definition head_of :: "('a \<Rightarrow> 'b::linorder) \<Rightarrow> 'a set \<Rightarrow> 'a set"
-  where "head_of f A = {a . a \<in> A \<and> f a = Max (f ` A)}"
-
-definition wq_head :: "state \<Rightarrow> cs \<Rightarrow> thread set"
-  where "wq_head s cs = head_of (cp s) (set (wq s cs))"
-
-lemma f_nil_simp: "\<lbrakk>f cs = []\<rbrakk> \<Longrightarrow> f(cs:=[]) = f"
-proof
-  fix x
-  assume h:"f cs = []"
-  show "(f(cs := [])) x = f x"
-  proof(cases "cs = x")
-    case True
-    with h show ?thesis by simp
-  next
-    case False
-    with h show ?thesis by simp
-  qed
-qed
-
-lemma step_back_vt: "vt ccs (e#s) \<Longrightarrow> vt ccs s"
-  by(ind_cases "vt ccs (e#s)", simp)
-
-lemma step_back_step: "vt ccs (e#s) \<Longrightarrow> ccs s e"
-  by(ind_cases "vt ccs (e#s)", simp)
-
-lemma holding_nil:
-    "\<lbrakk>wq s cs = []; holding (wq s) th cs\<rbrakk> \<Longrightarrow> False"
-  by (unfold cs_holding_def, auto)
-
-lemma waiting_kept_1: "
-       \<lbrakk>vt step (V th cs#s); wq s cs = a # list; waiting ((wq s)(cs := ab # aa @ lista @ ca)) t c;
-        lsp (cp s) list = (aa, ab # lista, ca)\<rbrakk>
-       \<Longrightarrow> waiting (wq s) t c"
-  apply (drule_tac step_back_vt, drule_tac wq_distinct[of _ cs])
-  apply(drule_tac lsp_set_eq)
-  by (unfold cs_waiting_def, auto split:if_splits)
- 
-lemma waiting_kept_2: 
-  "\<And>a list t c aa ca.
-       \<lbrakk>wq s cs = a # list; waiting ((wq s)(cs := [])) t c; lsp (cp s) list = (aa, [], ca)\<rbrakk>
-       \<Longrightarrow> waiting (wq s) t c"
-  apply(drule_tac lsp_set_eq)
-  by (unfold cs_waiting_def, auto split:if_splits)
-  
-
-lemma holding_nil_simp: "\<lbrakk>holding ((wq s)(cs := [])) t c\<rbrakk> \<Longrightarrow> holding (wq s) t c"
-  by(unfold cs_holding_def, auto)
-
-lemma step_wq_elim: "\<lbrakk>vt step (V th cs#s); wq s cs = a # list; a \<noteq> th\<rbrakk> \<Longrightarrow> False"
-  apply(drule_tac step_back_step)
-  apply(ind_cases "step s (V th cs)")
-  by(unfold s_holding_def, auto)
-
-lemma holding_cs_neq_simp: "c \<noteq> cs \<Longrightarrow> holding ((wq s)(cs := u)) t c = holding (wq s) t c"
-  by (unfold cs_holding_def, auto)
-
-lemma holding_th_neq_elim:
-  "\<And>a list c t aa ca ab lista.
-       \<lbrakk>\<not> holding (wq s) t c; holding ((wq s)(cs := ab # aa @ lista @ ca)) t c;
-         ab \<noteq> t\<rbrakk>
-       \<Longrightarrow> False"
-  by (unfold cs_holding_def, auto split:if_splits)
-
-lemma holding_nil_abs:
-  "\<not> holding ((wq s)(cs := [])) th cs"
-  by (unfold cs_holding_def, auto split:if_splits)
-
-lemma holding_abs: "\<lbrakk>holding ((wq s)(cs := ab # aa @ lista @ c)) th cs; ab \<noteq> th\<rbrakk>
-       \<Longrightarrow> False"
-    by (unfold cs_holding_def, auto split:if_splits)
-
-lemma waiting_abs: "\<not> waiting ((wq s)(cs := t # l @ r)) t cs"
-    by (unfold cs_waiting_def, auto split:if_splits)
-
-lemma waiting_abs_1: 
-  "\<lbrakk>\<not> waiting ((wq s)(cs := [])) t c; waiting (wq s) t c; c \<noteq> cs\<rbrakk>
-       \<Longrightarrow> False"
-    by (unfold cs_waiting_def, auto split:if_splits)
-
-lemma waiting_abs_2: "
-       \<lbrakk>\<not> waiting ((wq s)(cs := ab # aa @ lista @ ca)) t c; waiting (wq s) t c;
-        c \<noteq> cs\<rbrakk>
-       \<Longrightarrow> False"
-  by (unfold cs_waiting_def, auto split:if_splits)
-
-lemma waiting_abs_3:
-     "\<lbrakk>wq s cs = a # list; \<not> waiting ((wq s)(cs := [])) t c;
-        waiting (wq s) t c; lsp (cp s) list = (aa, [], ca)\<rbrakk>
-       \<Longrightarrow> False"
-  apply(drule_tac lsp_mid_nil, simp)
-  by(unfold cs_waiting_def, auto split:if_splits)
-
-lemma waiting_simp: "c \<noteq> cs \<Longrightarrow> waiting ((wq s)(cs:=z)) t c = waiting (wq s) t c"
-   by(unfold cs_waiting_def, auto split:if_splits)
-
-lemma holding_cs_eq:
-  "\<lbrakk>\<not> holding ((wq s)(cs := [])) t c; holding (wq s) t c\<rbrakk> \<Longrightarrow> c = cs"
-   by(unfold cs_holding_def, auto split:if_splits)
-
-lemma holding_cs_eq_1:
-  "\<lbrakk>\<not> holding ((wq s)(cs := ab # aa @ lista @ ca)) t c; holding (wq s) t c\<rbrakk>
-       \<Longrightarrow> c = cs"
-   by(unfold cs_holding_def, auto split:if_splits)
-
-lemma holding_th_eq: 
-       "\<lbrakk>vt step (V th cs#s); wq s cs = a # list; \<not> holding ((wq s)(cs := [])) t c; holding (wq s) t c;
-        lsp (cp s) list = (aa, [], ca)\<rbrakk>
-       \<Longrightarrow> t = th"
-  apply(drule_tac lsp_mid_nil, simp)
-  apply(unfold cs_holding_def, auto split:if_splits)
-  apply(drule_tac step_back_step)
-  apply(ind_cases "step s (V th cs)")
-  by (unfold s_holding_def, auto split:if_splits)
-
-lemma holding_th_eq_1:
-  "\<lbrakk>vt step (V th cs#s); 
-     wq s cs = a # list; \<not> holding ((wq s)(cs := ab # aa @ lista @ ca)) t c; holding (wq s) t c;
-        lsp (cp s) list = (aa, ab # lista, ca)\<rbrakk>
-       \<Longrightarrow> t = th"
-  apply(drule_tac step_back_step)
-  apply(ind_cases "step s (V th cs)")
-  apply(unfold s_holding_def cs_holding_def)
-  by (auto split:if_splits)
-
-lemma holding_th_eq_2: "\<lbrakk>holding ((wq s)(cs := ac # x)) th cs\<rbrakk>
-       \<Longrightarrow> ac = th"
-  by (unfold cs_holding_def, auto)
-
-lemma holding_th_eq_3: "
-       \<lbrakk>\<not> holding (wq s) t c;
-        holding ((wq s)(cs := ac # x)) t c\<rbrakk>
-       \<Longrightarrow> ac = t"
-  by (unfold cs_holding_def, auto)
-
-lemma holding_wq_eq: "holding ((wq s)(cs := th' # l @ r)) th' cs"
-   by (unfold cs_holding_def, auto)
-
-lemma waiting_th_eq: "
-       \<lbrakk>waiting (wq s) t c; wq s cs = a # list;
-        lsp (cp s) list = (aa, ac # lista, ba); \<not> waiting ((wq s)(cs := ac # aa @ lista @ ba)) t c\<rbrakk>
-       \<Longrightarrow> ac = t"
-  apply(drule_tac lsp_set_eq, simp)
-  by (unfold cs_waiting_def, auto split:if_splits)
-
-lemma step_depend_v:
-  "vt step (V th cs#s) \<Longrightarrow>
-  depend (V th cs # s) =
-  depend s - {(Cs cs, Th th)} -
-  {(Th th', Cs cs) |th'. \<exists>rest. wq s cs = th # rest \<and> (\<exists>l r. lsp (cp s) rest = (l, [th'], r))} \<union>
-  {(Cs cs, Th th') |th'. \<exists>rest. wq s cs = th # rest \<and> (\<exists>l r. lsp (cp s) rest = (l, [th'], r))}"
-  apply (unfold s_depend_def wq_def, 
-         auto split:list.splits simp:Let_def f_nil_simp holding_wq_eq, fold wq_def cp_def)
-  apply (auto split:list.splits prod.splits  
-               simp:Let_def f_nil_simp holding_nil_simp holding_cs_neq_simp holding_nil_abs
-                    waiting_abs waiting_simp holding_wq_eq
-               elim:holding_nil waiting_kept_1 waiting_kept_2 step_wq_elim holding_th_neq_elim 
-               holding_abs waiting_abs_1 waiting_abs_3 holding_cs_eq holding_cs_eq_1
-               holding_th_eq holding_th_eq_1 holding_th_eq_2 holding_th_eq_3 waiting_th_eq
-               dest:lsp_mid_length)
-  done
-
-lemma step_depend_p:
-  "vt step (P th cs#s) \<Longrightarrow>
-  depend (P th cs # s) =  (if (wq s cs = []) then depend s \<union> {(Cs cs, Th th)}
-                                             else depend s \<union> {(Th th, Cs cs)})"
-  apply(unfold s_depend_def wq_def)
-  apply (auto split:list.splits prod.splits simp:Let_def cs_waiting_def cs_holding_def)
-  apply(case_tac "c = cs", auto)
-  apply(fold wq_def)
-  apply(drule_tac step_back_step)
-  by (ind_cases " step s (P (hd (wq s cs)) cs)", 
-    auto simp:s_depend_def wq_def cs_holding_def)
-
-lemma simple_A:
-  fixes A
-  assumes h: "\<And> x y. \<lbrakk>x \<in> A; y \<in> A\<rbrakk> \<Longrightarrow> x = y"
-  shows "A = {} \<or> (\<exists> a. A = {a})"
-proof(cases "A = {}")
-  case True thus ?thesis by simp
-next
-  case False then obtain a where "a \<in> A" by auto
-  with h have "A = {a}" by auto
-  thus ?thesis by simp
-qed
-
-lemma depend_target_th: "(Th th, x) \<in> depend (s::state) \<Longrightarrow> \<exists> cs. x = Cs cs"
-  by (unfold s_depend_def, auto)
-
-lemma acyclic_depend: 
-  fixes s
-  assumes vt: "vt step s"
-  shows "acyclic (depend s)"
-proof -
-  from vt show ?thesis
-  proof(induct)
-    case (vt_cons s e)
-    assume ih: "acyclic (depend s)"
-      and stp: "step s e"
-      and vt: "vt step s"
-    show ?case
-    proof(cases e)
-      case (Create th prio)
-      with ih
-      show ?thesis by (simp add:depend_create_unchanged)
-    next
-      case (Exit th)
-      with ih show ?thesis by (simp add:depend_exit_unchanged)
-    next
-      case (V th cs)
-      from V vt stp have vtt: "vt step (V th cs#s)" by auto
-      from step_depend_v [OF this]
-      have eq_de: "depend (e # s) = 
-        depend s - {(Cs cs, Th th)} -
-        {(Th th', Cs cs) |th'. \<exists>rest. wq s cs = th # rest \<and> (\<exists>l r. lsp (cp s) rest = (l, [th'], r))} \<union>
-        {(Cs cs, Th th') |th'. \<exists>rest. wq s cs = th # rest \<and> (\<exists>l r. lsp (cp s) rest = (l, [th'], r))}"
-        (is "?L = (?A - ?B - ?C) \<union> ?D") by (simp add:V)
-      from ih have ac: "acyclic (?A - ?B - ?C)" by (auto elim:acyclic_subset)
-      have "?D = {} \<or> (\<exists> a. ?D = {a})" by (rule simple_A, auto)
-      thus ?thesis
-      proof(cases "wq s cs")
-        case Nil
-        hence "?D = {}" by simp
-        with ac and eq_de show ?thesis by simp
-      next
-        case (Cons tth rest)
-        from stp and V have "step s (V th cs)" by simp
-        hence eq_wq: "wq s cs = th # rest"
-        proof -
-          show "step s (V th cs) \<Longrightarrow> wq s cs = th # rest"
-            apply(ind_cases "step s (V th cs)")
-            by(insert Cons, unfold s_holding_def, simp)
-        qed
-        show ?thesis
-        proof(cases "lsp (cp s) rest")
-          fix l b r
-          assume eq_lsp: "lsp (cp s) rest = (l, b, r) "
-          show ?thesis
-          proof(cases "b")
-            case Nil
-            with eq_lsp and eq_wq have "?D = {}" by simp
-            with ac and eq_de show ?thesis by simp
-          next
-            case (Cons th' m)
-            with eq_lsp 
-            have eq_lsp: "lsp (cp s) rest = (l, [th'], r)" 
-              apply simp
-              by (drule_tac lsp_mid_length, simp)
-            from eq_wq and eq_lsp
-            have eq_D: "?D = {(Cs cs, Th th')}" by auto
-            from eq_wq and eq_lsp
-            have eq_C: "?C = {(Th th', Cs cs)}" by auto
-            let ?E = "(?A - ?B - ?C)"
-            have "(Th th', Cs cs) \<notin> ?E\<^sup>*"
-            proof
-              assume "(Th th', Cs cs) \<in> ?E\<^sup>*"
-              hence " (Th th', Cs cs) \<in> ?E\<^sup>+" by (simp add: rtrancl_eq_or_trancl)
-              from tranclD [OF this]
-              obtain x where th'_e: "(Th th', x) \<in> ?E" by blast
-              hence th_d: "(Th th', x) \<in> ?A" by simp
-              from depend_target_th [OF this]
-              obtain cs' where eq_x: "x = Cs cs'" by auto
-              with th_d have "(Th th', Cs cs') \<in> ?A" by simp
-              hence wt_th': "waiting s th' cs'"
-                unfolding s_depend_def s_waiting_def cs_waiting_def by simp
-              hence "cs' = cs"
-              proof(rule waiting_unique [OF vt])
-                from eq_wq eq_lsp wq_distinct[OF vt, of cs]
-                show "waiting s th' cs" by(unfold s_waiting_def, auto dest:lsp_set_eq)
-              qed
-              with th'_e eq_x have "(Th th', Cs cs) \<in> ?E" by simp
-              with eq_C show "False" by simp
-            qed
-            with acyclic_insert[symmetric] and ac and eq_D
-            and eq_de show ?thesis by simp
-          qed 
-        qed
-      qed
-    next
-      case (P th cs)
-      from P vt stp have vtt: "vt step (P th cs#s)" by auto
-      from step_depend_p [OF this] P
-      have "depend (e # s) = 
-              (if wq s cs = [] then depend s \<union> {(Cs cs, Th th)} else 
-                                    depend s \<union> {(Th th, Cs cs)})" (is "?L = ?R")
-        by simp
-      moreover have "acyclic ?R"
-      proof(cases "wq s cs = []")
-        case True
-        hence eq_r: "?R =  depend s \<union> {(Cs cs, Th th)}" by simp
-        have "(Th th, Cs cs) \<notin> (depend s)\<^sup>*"
-        proof
-          assume "(Th th, Cs cs) \<in> (depend s)\<^sup>*"
-          hence "(Th th, Cs cs) \<in> (depend s)\<^sup>+" by (simp add: rtrancl_eq_or_trancl)
-          from tranclD2 [OF this]
-          obtain x where "(x, Cs cs) \<in> depend s" by auto
-          with True show False by (auto simp:s_depend_def cs_waiting_def)
-        qed
-        with acyclic_insert ih eq_r show ?thesis by auto
-      next
-        case False
-        hence eq_r: "?R =  depend s \<union> {(Th th, Cs cs)}" by simp
-        have "(Cs cs, Th th) \<notin> (depend s)\<^sup>*"
-        proof
-          assume "(Cs cs, Th th) \<in> (depend s)\<^sup>*"
-          hence "(Cs cs, Th th) \<in> (depend s)\<^sup>+" by (simp add: rtrancl_eq_or_trancl)
-          moreover from step_back_step [OF vtt] have "step s (P th cs)" .
-          ultimately show False
-          proof -
-            show " \<lbrakk>(Cs cs, Th th) \<in> (depend s)\<^sup>+; step s (P th cs)\<rbrakk> \<Longrightarrow> False"
-              by (ind_cases "step s (P th cs)", simp)
-          qed
-        qed
-        with acyclic_insert ih eq_r show ?thesis by auto
-      qed
-      ultimately show ?thesis by simp
-    next
-      case (Set thread prio)
-      with ih
-      thm depend_set_unchanged
-      show ?thesis by (simp add:depend_set_unchanged)
-    qed
-  next
-    case vt_nil
-    show "acyclic (depend ([]::state))"
-      by (auto simp: s_depend_def cs_waiting_def 
-                      cs_holding_def wq_def acyclic_def)
-  qed
-qed
-
-lemma finite_depend: 
-  fixes s
-  assumes vt: "vt step s"
-  shows "finite (depend s)"
-proof -
-  from vt show ?thesis
-  proof(induct)
-    case (vt_cons s e)
-    assume ih: "finite (depend s)"
-      and stp: "step s e"
-      and vt: "vt step s"
-    show ?case
-    proof(cases e)
-      case (Create th prio)
-      with ih
-      show ?thesis by (simp add:depend_create_unchanged)
-    next
-      case (Exit th)
-      with ih show ?thesis by (simp add:depend_exit_unchanged)
-    next
-      case (V th cs)
-      from V vt stp have vtt: "vt step (V th cs#s)" by auto
-      from step_depend_v [OF this]
-      have eq_de: "depend (e # s) = 
-        depend s - {(Cs cs, Th th)} -
-        {(Th th', Cs cs) |th'. \<exists>rest. wq s cs = th # rest \<and> (\<exists>l r. lsp (cp s) rest = (l, [th'], r))} \<union>
-        {(Cs cs, Th th') |th'. \<exists>rest. wq s cs = th # rest \<and> (\<exists>l r. lsp (cp s) rest = (l, [th'], r))}"
-        (is "?L = (?A - ?B - ?C) \<union> ?D") by (simp add:V)
-      moreover from ih have ac: "finite (?A - ?B - ?C)" by simp
-      moreover have "finite ?D"
-      proof -
-        have "?D = {} \<or> (\<exists> a. ?D = {a})" by (rule simple_A, auto)
-        thus ?thesis
-        proof
-          assume h: "?D = {}"
-          show ?thesis by (unfold h, simp)
-        next
-          assume "\<exists> a. ?D = {a}"
-          thus ?thesis by auto
-        qed
-      qed
-      ultimately show ?thesis by simp
-    next
-      case (P th cs)
-      from P vt stp have vtt: "vt step (P th cs#s)" by auto
-      from step_depend_p [OF this] P
-      have "depend (e # s) = 
-              (if wq s cs = [] then depend s \<union> {(Cs cs, Th th)} else 
-                                    depend s \<union> {(Th th, Cs cs)})" (is "?L = ?R")
-        by simp
-      moreover have "finite ?R"
-      proof(cases "wq s cs = []")
-        case True
-        hence eq_r: "?R =  depend s \<union> {(Cs cs, Th th)}" by simp
-        with True and ih show ?thesis by auto
-      next
-        case False
-        hence "?R = depend s \<union> {(Th th, Cs cs)}" by simp
-        with False and ih show ?thesis by auto
-      qed
-      ultimately show ?thesis by auto
-    next
-      case (Set thread prio)
-      with ih
-      show ?thesis by (simp add:depend_set_unchanged)
-    qed
-  next
-    case vt_nil
-    show "finite (depend ([]::state))"
-      by (auto simp: s_depend_def cs_waiting_def 
-                   cs_holding_def wq_def acyclic_def)
-  qed
-qed
-
-text {* Several useful lemmas *}
-
-thm wf_trancl
-thm finite_acyclic_wf
-thm finite_acyclic_wf_converse
-thm wf_induct
-
-
-lemma wf_dep_converse: 
-  fixes s
-  assumes vt: "vt step s"
-  shows "wf ((depend s)^-1)"
-proof(rule finite_acyclic_wf_converse)
-  from finite_depend [OF vt]
-  show "finite (depend s)" .
-next
-  from acyclic_depend[OF vt]
-  show "acyclic (depend s)" .
-qed
-
-lemma hd_np_in: "x \<in> set l \<Longrightarrow> hd l \<in> set l"
-by (induct l, auto)
-
-lemma th_chasing: "(Th th, Cs cs) \<in> depend (s::state) \<Longrightarrow> \<exists> th'. (Cs cs, Th th') \<in> depend s"
-  by (auto simp:s_depend_def s_holding_def cs_holding_def cs_waiting_def wq_def dest:hd_np_in)
-
-lemma wq_threads: 
-  fixes s cs
-  assumes vt: "vt step s"
-  and h: "th \<in> set (wq s cs)"
-  shows "th \<in> threads s"
-proof -
- from vt and h show ?thesis
-  proof(induct arbitrary: th cs)
-    case (vt_cons s e)
-    assume ih: "\<And>th cs. th \<in> set (wq s cs) \<Longrightarrow> th \<in> threads s"
-      and stp: "step s e"
-      and vt: "vt step s"
-      and h: "th \<in> set (wq (e # s) cs)"
-    show ?case
-    proof(cases e)
-      case (Create th' prio)
-      with ih h show ?thesis
-        by (auto simp:wq_def Let_def)
-    next
-      case (Exit th')
-      with stp ih h show ?thesis
-        apply (auto simp:wq_def Let_def)
-        apply (ind_cases "step s (Exit th')")
-        apply (auto simp:runing_def readys_def s_holding_def s_waiting_def holdents_def
-               s_depend_def s_holding_def cs_holding_def)
-        by (fold wq_def, auto)
-    next
-      case (V th' cs')
-      show ?thesis
-      proof(cases "cs' = cs")
-        case False
-        with h
-        show ?thesis
-          apply(unfold wq_def V, auto simp:Let_def V split:prod.splits, fold wq_def)
-          by (drule_tac ih, simp)
-      next
-        case True
-        from h
-        show ?thesis
-        proof(unfold V wq_def)
-          assume th_in: "th \<in> set (waiting_queue (schs (V th' cs' # s)) cs)" (is "th \<in> set ?l")
-          show "th \<in> threads (V th' cs' # s)"
-          proof(cases "cs = cs'")
-            case False
-            hence "?l = waiting_queue (schs s) cs" by (simp add:Let_def)
-            with th_in have " th \<in> set (wq s cs)" 
-              by (fold wq_def, simp)
-            from ih [OF this] show ?thesis by simp
-          next
-            case True
-            show ?thesis
-            proof(cases "waiting_queue (schs s) cs'")
-              case Nil
-              with h V show ?thesis
-                apply (auto simp:wq_def Let_def split:if_splits)
-                by (fold wq_def, drule_tac ih, simp)
-            next
-              case (Cons a rest)
-              assume eq_wq: "waiting_queue (schs s) cs' = a # rest"
-              with h V show ?thesis
-              proof(cases "(lsp (cur_preced (schs s)) rest)", unfold V)
-                fix l m r
-                assume eq_lsp: "lsp (cur_preced (schs s)) rest = (l, m, r)"
-                  and eq_wq: "waiting_queue (schs s) cs' = a # rest"
-                  and th_in_set: "th \<in> set (wq (V th' cs' # s) cs)"
-                show ?thesis
-                proof(cases "m")
-                  case Nil
-                  with eq_lsp have "rest = []" using lsp_mid_nil by auto
-                  with eq_wq have "waiting_queue (schs s) cs' = [a]" by simp
-                  with h[unfolded V wq_def] True 
-                  show ?thesis
-                    by (simp add:Let_def)
-                next
-                  case (Cons b rb)
-                  with lsp_mid_length[OF eq_lsp] have eq_m: "m = [b]" by auto
-                  with eq_lsp have "lsp (cur_preced (schs s)) rest = (l, [b], r)" by simp
-                  with h[unfolded V wq_def] True lsp_set_eq [OF this] eq_wq
-                  show ?thesis
-                    apply (auto simp:Let_def, fold wq_def)
-                    by (rule_tac ih [of _ cs'], auto)+
-                qed
-              qed
-            qed
-          qed
-        qed
-      qed
-    next
-      case (P th' cs')
-      from h stp
-      show ?thesis
-        apply (unfold P wq_def)
-        apply (auto simp:Let_def split:if_splits, fold wq_def)
-        apply (auto intro:ih)
-        apply(ind_cases "step s (P th' cs')")
-        by (unfold runing_def readys_def, auto)
-    next
-      case (Set thread prio)
-      with ih h show ?thesis
-        by (auto simp:wq_def Let_def)
-    qed
-  next
-    case vt_nil
-    thus ?case by (auto simp:wq_def)
-  qed
-qed
-
-lemma range_in: "\<lbrakk>vt step s; (Th th) \<in> Range (depend (s::state))\<rbrakk> \<Longrightarrow> th \<in> threads s"
-  apply(unfold s_depend_def cs_waiting_def cs_holding_def)
-  by (auto intro:wq_threads)
-
-lemma readys_v_eq:
-  fixes th thread cs rest
-  assumes neq_th: "th \<noteq> thread"
-  and eq_wq: "wq s cs = thread#rest"
-  and not_in: "th \<notin>  set rest"
-  shows "(th \<in> readys (V thread cs#s)) = (th \<in> readys s)"
-proof -
-  from prems show ?thesis
-    apply (auto simp:readys_def)
-    apply (case_tac "cs = csa", simp add:s_waiting_def)
-    apply (erule_tac x = csa in allE)
-    apply (simp add:s_waiting_def wq_def Let_def split:if_splits)
-    apply (case_tac "csa = cs", simp)
-    apply (erule_tac x = cs in allE)
-    by (auto simp:s_waiting_def wq_def Let_def split:list.splits prod.splits 
-            dest:lsp_set_eq)
-qed
-
-lemma readys_v_eq_1:
-  fixes th thread cs rest
-  assumes neq_th: "th \<noteq> thread"
-  and eq_wq: "wq s cs = thread#rest"
-  and eq_lsp: "lsp (cp s) rest = (l, [th'], r)"
-  and neq_th': "th \<noteq> th'"
-  shows "(th \<in> readys (V thread cs#s)) = (th \<in> readys s)"
-proof -
-  from prems show ?thesis
-    apply (auto simp:readys_def)
-    apply (case_tac "cs = csa", simp add:s_waiting_def)
-    apply (erule_tac x = cs in allE)
-    apply (simp add:s_waiting_def wq_def Let_def split:prod.splits list.splits)
-    apply (drule_tac lsp_mid_nil,simp, clarify, fold cp_def, clarsimp)
-    apply (frule_tac lsp_set_eq, simp)
-    apply (erule_tac x = csa in allE)
-    apply (subst (asm) (2) s_waiting_def, unfold wq_def)
-    apply (auto simp:Let_def split:list.splits prod.splits if_splits 
-            dest:lsp_set_eq)
-    apply (unfold s_waiting_def)
-    apply (fold wq_def, clarsimp)
-    apply (clarsimp)+
-    apply (case_tac "csa = cs", simp)
-    apply (erule_tac x = cs in allE, simp)
-    apply (unfold wq_def)
-    by (auto simp:Let_def split:list.splits prod.splits if_splits 
-            dest:lsp_set_eq)
-qed
-
-lemma readys_v_eq_2:
-  fixes th thread cs rest
-  assumes neq_th: "th \<noteq> thread"
-  and eq_wq: "wq s cs = thread#rest"
-  and eq_lsp: "lsp (cp s) rest = (l, [th'], r)"
-  and neq_th': "th = th'"
-  and vt: "vt step s"
-  shows "(th \<in> readys (V thread cs#s))"
-proof -
-  from prems show ?thesis
-    apply (auto simp:readys_def)
-    apply (rule_tac wq_threads [of s _ cs], auto dest:lsp_set_eq)
-    apply (unfold s_waiting_def wq_def)
-    apply (auto simp:Let_def split:list.splits prod.splits if_splits 
-            dest:lsp_set_eq lsp_mid_nil lsp_mid_length)
-    apply (fold cp_def, simp+, clarsimp)
-    apply (frule_tac lsp_set_eq, simp)
-    apply (fold wq_def)
-    apply (subgoal_tac "csa = cs", simp)
-    apply (rule_tac waiting_unique [of s th'], simp)
-    by (auto simp:s_waiting_def)
-qed
-
-lemma chain_building:
-  assumes vt: "vt step s"
-  shows "node \<in> Domain (depend s) \<longrightarrow> (\<exists> th'. th' \<in> readys s \<and> (node, Th th') \<in> (depend s)^+)"
-proof -
-  from wf_dep_converse [OF vt]
-  have h: "wf ((depend s)\<inverse>)" .
-  show ?thesis
-  proof(induct rule:wf_induct [OF h])
-    fix x
-    assume ih [rule_format]: 
-      "\<forall>y. (y, x) \<in> (depend s)\<inverse> \<longrightarrow> 
-           y \<in> Domain (depend s) \<longrightarrow> (\<exists>th'. th' \<in> readys s \<and> (y, Th th') \<in> (depend s)\<^sup>+)"
-    show "x \<in> Domain (depend s) \<longrightarrow> (\<exists>th'. th' \<in> readys s \<and> (x, Th th') \<in> (depend s)\<^sup>+)"
-    proof
-      assume x_d: "x \<in> Domain (depend s)"
-      show "\<exists>th'. th' \<in> readys s \<and> (x, Th th') \<in> (depend s)\<^sup>+"
-      proof(cases x)
-        case (Th th)
-        from x_d Th obtain cs where x_in: "(Th th, Cs cs) \<in> depend s" by (auto simp:s_depend_def)
-        with Th have x_in_r: "(Cs cs, x) \<in> (depend s)^-1" by simp
-        from th_chasing [OF x_in] obtain th' where "(Cs cs, Th th') \<in> depend s" by blast
-        hence "Cs cs \<in> Domain (depend s)" by auto
-        from ih [OF x_in_r this] obtain th'
-          where th'_ready: " th' \<in> readys s" and cs_in: "(Cs cs, Th th') \<in> (depend s)\<^sup>+" by auto
-        have "(x, Th th') \<in> (depend s)\<^sup>+" using Th x_in cs_in by auto
-        with th'_ready show ?thesis by auto
-      next
-        case (Cs cs)
-        from x_d Cs obtain th' where th'_d: "(Th th', x) \<in> (depend s)^-1" by (auto simp:s_depend_def)
-        show ?thesis
-        proof(cases "th' \<in> readys s")
-          case True
-          from True and th'_d show ?thesis by auto
-        next
-          case False
-          from th'_d and range_in [OF vt] have "th' \<in> threads s" by auto
-          with False have "Th th' \<in> Domain (depend s)" 
-            by (auto simp:readys_def s_waiting_def s_depend_def cs_waiting_def Domain_def)
-          from ih [OF th'_d this]
-          obtain th'' where 
-            th''_r: "th'' \<in> readys s" and 
-            th''_in: "(Th th', Th th'') \<in> (depend s)\<^sup>+" by auto
-          from th'_d and th''_in 
-          have "(x, Th th'') \<in> (depend s)\<^sup>+" by auto
-          with th''_r show ?thesis by auto
-        qed
-      qed
-    qed
-  qed
-qed
-
-lemma th_chain_to_ready:
-  fixes s th
-  assumes vt: "vt step s"
-  and th_in: "th \<in> threads s"
-  shows "th \<in> readys s \<or> (\<exists> th'. th' \<in> readys s \<and> (Th th, Th th') \<in> (depend s)^+)"
-proof(cases "th \<in> readys s")
-  case True
-  thus ?thesis by auto
-next
-  case False
-  from False and th_in have "Th th \<in> Domain (depend s)" 
-    by (auto simp:readys_def s_waiting_def s_depend_def cs_waiting_def Domain_def)
-  from chain_building [rule_format, OF vt this]
-  show ?thesis by auto
-qed
-
-lemma waiting_eq: "waiting s th cs = waiting (wq s) th cs"
-  by  (unfold s_waiting_def cs_waiting_def, auto)
-
-lemma holding_eq: "holding (s::state) th cs = holding (wq s) th cs"
-  by (unfold s_holding_def cs_holding_def, simp)
-
-lemma holding_unique: "\<lbrakk>holding (s::state) th1 cs; holding s th2 cs\<rbrakk> \<Longrightarrow> th1 = th2"
-  by (unfold s_holding_def cs_holding_def, auto)
-
-lemma unique_depend: "\<lbrakk>vt step s; (n, n1) \<in> depend s; (n, n2) \<in> depend s\<rbrakk> \<Longrightarrow> n1 = n2"
-  apply(unfold s_depend_def, auto, fold waiting_eq holding_eq)
-  by(auto elim:waiting_unique holding_unique)
-
-lemma trancl_split: "(a, b) \<in> r^+ \<Longrightarrow> \<exists> c. (a, c) \<in> r"
-by (induct rule:trancl_induct, auto)
-
-lemma dchain_unique:
-  assumes vt: "vt step s"
-  and th1_d: "(n, Th th1) \<in> (depend s)^+"
-  and th1_r: "th1 \<in> readys s"
-  and th2_d: "(n, Th th2) \<in> (depend s)^+"
-  and th2_r: "th2 \<in> readys s"
-  shows "th1 = th2"
-proof -
-  { assume neq: "th1 \<noteq> th2"
-    hence "Th th1 \<noteq> Th th2" by simp
-    from unique_chain [OF _ th1_d th2_d this] and unique_depend [OF vt]
-    have "(Th th1, Th th2) \<in> (depend s)\<^sup>+ \<or> (Th th2, Th th1) \<in> (depend s)\<^sup>+" by auto
-    hence "False"
-    proof
-      assume "(Th th1, Th th2) \<in> (depend s)\<^sup>+"
-      from trancl_split [OF this]
-      obtain n where dd: "(Th th1, n) \<in> depend s" by auto
-      then obtain cs where eq_n: "n = Cs cs"
-        by (auto simp:s_depend_def s_holding_def cs_holding_def cs_waiting_def wq_def dest:hd_np_in)
-      from dd eq_n have "th1 \<notin> readys s"
-        by (auto simp:readys_def s_depend_def s_waiting_def cs_waiting_def)
-      with th1_r show ?thesis by auto
-    next
-      assume "(Th th2, Th th1) \<in> (depend s)\<^sup>+"
-      from trancl_split [OF this]
-      obtain n where dd: "(Th th2, n) \<in> depend s" by auto
-      then obtain cs where eq_n: "n = Cs cs"
-        by (auto simp:s_depend_def s_holding_def cs_holding_def cs_waiting_def wq_def dest:hd_np_in)
-      from dd eq_n have "th2 \<notin> readys s"
-        by (auto simp:readys_def s_depend_def s_waiting_def cs_waiting_def)
-      with th2_r show ?thesis by auto
-    qed
-  } thus ?thesis by auto
-qed
-             
-definition count :: "('a \<Rightarrow> bool) \<Rightarrow> 'a list \<Rightarrow> nat"
-where "count Q l = length (filter Q l)"
-
-definition cntP :: "state \<Rightarrow> thread \<Rightarrow> nat"
-where "cntP s th = count (\<lambda> e. \<exists> cs. e = P th cs) s"
-
-definition cntV :: "state \<Rightarrow> thread \<Rightarrow> nat"
-where "cntV s th = count (\<lambda> e. \<exists> cs. e = V th cs) s"
-
-
-lemma step_holdents_p_add:
-  fixes th cs s
-  assumes vt: "vt step (P th cs#s)"
-  and "wq s cs = []"
-  shows "holdents (P th cs#s) th = holdents s th \<union> {cs}"
-proof -
-  from prems show ?thesis
-  unfolding  holdents_def step_depend_p[OF vt] by auto
-qed
-
-lemma step_holdents_p_eq:
-  fixes th cs s
-  assumes vt: "vt step (P th cs#s)"
-  and "wq s cs \<noteq> []"
-  shows "holdents (P th cs#s) th = holdents s th"
-proof -
-  from prems show ?thesis
-  unfolding  holdents_def step_depend_p[OF vt] by auto
-qed
-
-lemma step_holdents_v_minus:
-  fixes th cs s
-  assumes vt: "vt step (V th cs#s)"
-  shows "holdents (V th cs#s) th = holdents s th - {cs}"
-proof -
-  { fix rest l r
-    assume eq_wq: "wq s cs = th # rest" 
-      and eq_lsp: "lsp (cp s) rest = (l, [th], r)"
-    have "False" 
-    proof -
-      from lsp_set_eq [OF eq_lsp] have " rest = l @ [th] @ r" .
-      with eq_wq have "wq s cs = th#\<dots>" by simp
-      with wq_distinct [OF step_back_vt[OF vt], of cs]
-      show ?thesis by auto
-    qed
-  } thus ?thesis unfolding holdents_def step_depend_v[OF vt] by auto
-qed
-
-lemma step_holdents_v_add:
-  fixes th th' cs s rest l r
-  assumes vt: "vt step (V th' cs#s)"
-  and neq_th: "th \<noteq> th'" 
-  and eq_wq: "wq s cs = th' # rest"
-  and eq_lsp: "lsp (cp s) rest = (l, [th], r)"
-  shows "holdents (V th' cs#s) th = holdents s th \<union> {cs}"
-proof -
-  from prems show ?thesis
-  unfolding  holdents_def step_depend_v[OF vt] by auto
-qed
-
-lemma step_holdents_v_eq:
-  fixes th th' cs s rest l r th''
-  assumes vt: "vt step (V th' cs#s)"
-  and neq_th: "th \<noteq> th'" 
-  and eq_wq: "wq s cs = th' # rest"
-  and eq_lsp: "lsp (cp s) rest = (l, [th''], r)"
-  and neq_th': "th \<noteq> th''"
-  shows "holdents (V th' cs#s) th = holdents s th"
-proof -
-  from prems show ?thesis
-  unfolding  holdents_def step_depend_v[OF vt] by auto
-qed
-
-definition cntCS :: "state \<Rightarrow> thread \<Rightarrow> nat"
-where "cntCS s th = card (holdents s th)"
-
-lemma cntCS_v_eq:
-  fixes th thread cs rest
-  assumes neq_th: "th \<noteq> thread"
-  and eq_wq: "wq s cs = thread#rest"
-  and not_in: "th \<notin>  set rest"
-  and vtv: "vt step (V thread cs#s)"
-  shows "cntCS (V thread cs#s) th = cntCS s th"
-proof -
-  from prems show ?thesis
-    apply (unfold cntCS_def holdents_def step_depend_v)
-    apply auto
-    apply (subgoal_tac "\<not>  (\<exists>l r. lsp (cp s) rest = (l, [th], r))", auto)
-    by (drule_tac lsp_set_eq, auto)
-qed
-
-lemma cntCS_v_eq_1:
-  fixes th thread cs rest
-  assumes neq_th: "th \<noteq> thread"
-  and eq_wq: "wq s cs = thread#rest"
-  and eq_lsp: "lsp (cp s) rest = (l, [th'], r)"
-  and neq_th': "th \<noteq> th'"
-  and vtv: "vt step (V thread cs#s)"
-  shows "cntCS (V thread cs#s) th = cntCS s th"
-proof -
-  from prems show ?thesis
-    apply (unfold cntCS_def holdents_def step_depend_v)
-    by auto
-qed
-
-fun the_cs :: "node \<Rightarrow> cs"
-where "the_cs (Cs cs) = cs"
-
-lemma cntCS_v_eq_2:
-  fixes th thread cs rest
-  assumes neq_th: "th \<noteq> thread"
-  and eq_wq: "wq s cs = thread#rest"
-  and eq_lsp: "lsp (cp s) rest = (l, [th'], r)"
-  and neq_th': "th = th'"
-  and vtv: "vt step (V thread cs#s)"
-  shows "cntCS (V thread cs#s) th = 1 + cntCS s th"
-proof -
-  have "card {csa. csa = cs \<or> (Cs csa, Th th') \<in> depend s} = 
-                     Suc (card {cs. (Cs cs, Th th') \<in> depend s})" 
-    (is "card ?A = Suc (card ?B)")
-  proof -
-    have h: "?A = insert cs ?B" by auto
-    moreover have h1: "?B = ?B - {cs}"
-    proof -
-      { assume "(Cs cs, Th th') \<in> depend s"
-        moreover have "(Th th', Cs cs) \<in> depend s"
-        proof -
-          from wq_distinct [OF step_back_vt[OF vtv], of cs]
-          eq_wq lsp_set_eq [OF eq_lsp] show ?thesis
-            apply (auto simp:s_depend_def)
-            by (unfold cs_waiting_def, auto)
-        qed
-        moreover note acyclic_depend [OF step_back_vt[OF vtv]]
-        ultimately have "False"
-          apply (auto simp:acyclic_def)
-          apply (erule_tac x="Cs cs" in allE)
-          apply (subgoal_tac "(Cs cs, Cs cs) \<in> (depend s)\<^sup>+", simp)
-          by (rule_tac trancl_into_trancl [where b = "Th th'"], auto)
-      } thus ?thesis by auto
-    qed
-    moreover have "card (insert cs ?B) = Suc (card (?B - {cs}))"
-    proof(rule card_insert)
-      from finite_depend [OF step_back_vt [OF vtv]]
-      have fnt: "finite (depend s)" .
-      show " finite {cs. (Cs cs, Th th') \<in> depend s}" (is "finite ?B")
-      proof -
-        have "?B \<subseteq>  (\<lambda> (a, b). the_cs a) ` (depend s)"
-          apply (auto simp:image_def)
-          by (rule_tac x = "(Cs x, Th th')" in bexI, auto)
-        with fnt show ?thesis by (auto intro:finite_subset)
-      qed
-    qed
-    ultimately show ?thesis by simp
-  qed
-  with prems show ?thesis
-    apply (unfold cntCS_def holdents_def step_depend_v[OF vtv])
-    by auto
-qed
-
-lemma finite_holding:
-  fixes s th cs
-  assumes vt: "vt step s"
-  shows "finite (holdents s th)"
-proof -
-  let ?F = "\<lambda> (x, y). the_cs x"
-  from finite_depend [OF vt]
-  have "finite (depend s)" .
-  hence "finite (?F `(depend s))" by simp
-  moreover have "{cs . (Cs cs, Th th) \<in> depend s} \<subseteq> \<dots>" 
-  proof -
-    { have h: "\<And> a A f. a \<in> A \<Longrightarrow> f a \<in> f ` A" by auto
-      fix x assume "(Cs x, Th th) \<in> depend s"
-      hence "?F (Cs x, Th th) \<in> ?F `(depend s)" by (rule h)
-      moreover have "?F (Cs x, Th th) = x" by simp
-      ultimately have "x \<in> (\<lambda>(x, y). the_cs x) ` depend s" by simp 
-    } thus ?thesis by auto
-  qed
-  ultimately show ?thesis by (unfold holdents_def, auto intro:finite_subset)
-qed
-
-inductive_cases case_step_v: "step s (V thread cs)"
-
-lemma cntCS_v_dec: 
-  fixes s thread cs
-  assumes vtv: "vt step (V thread cs#s)"
-  shows "(cntCS (V thread cs#s) thread + 1) = cntCS s thread"
-proof -
-  have cs_in: "cs \<in> holdents s thread" using step_back_step[OF vtv]
-    apply (erule_tac case_step_v)
-    apply (unfold holdents_def s_depend_def, simp)
-    by (unfold cs_holding_def s_holding_def, auto)
-  moreover have cs_not_in: 
-    "(holdents (V thread cs#s) thread) = holdents s thread - {cs}"
-    apply (insert wq_distinct[OF step_back_vt[OF vtv], of cs])
-    by (unfold holdents_def, unfold step_depend_v[OF vtv], 
-            auto dest:lsp_set_eq)
-  ultimately 
-  have "holdents s thread = insert cs (holdents (V thread cs#s) thread)"
-    by auto
-  moreover have "card \<dots> = 
-                    Suc (card ((holdents (V thread cs#s) thread) - {cs}))"
-  proof(rule card_insert)
-    from finite_holding [OF vtv]
-    show " finite (holdents (V thread cs # s) thread)" .
-  qed
-  moreover from cs_not_in 
-  have "cs \<notin> (holdents (V thread cs#s) thread)" by auto
-  ultimately show ?thesis by (simp add:cntCS_def)
-qed 
-
-lemma cnp_cnv_cncs:
-  fixes s th
-  assumes vt: "vt step s"
-  shows "cntP s th = cntV s th + (if (th \<in> readys s \<or> th \<notin> threads s) 
-                                       then cntCS s th else cntCS s th + 1)"
-proof -
-  from vt show ?thesis
-  proof(induct arbitrary:th)
-    case (vt_cons s e)
-    assume vt: "vt step s"
-    and ih: "\<And>th. cntP s th  = cntV s th +
-               (if (th \<in> readys s \<or> th \<notin> threads s) then cntCS s th else cntCS s th + 1)"
-    and stp: "step s e"
-    from stp show ?case
-    proof(cases)
-      case (thread_create prio max_prio thread)
-      assume eq_e: "e = Create thread prio"
-        and not_in: "thread \<notin> threads s"
-      show ?thesis
-      proof -
-        { fix cs 
-          assume "thread \<in> set (wq s cs)"
-          from wq_threads [OF vt this] have "thread \<in> threads s" .
-          with not_in have "False" by simp
-        } with eq_e have eq_readys: "readys (e#s) = readys s \<union> {thread}"
-          by (auto simp:readys_def threads.simps s_waiting_def 
-            wq_def cs_waiting_def Let_def)
-        from eq_e have eq_cnp: "cntP (e#s) th = cntP s th" by (simp add:cntP_def count_def)
-        from eq_e have eq_cnv: "cntV (e#s) th = cntV s th" by (simp add:cntV_def count_def)
-        have eq_cncs: "cntCS (e#s) th = cntCS s th"
-          unfolding cntCS_def holdents_def
-          by (simp add:depend_create_unchanged eq_e)
-        { assume "th \<noteq> thread"
-          with eq_readys eq_e
-          have "(th \<in> readys (e # s) \<or> th \<notin> threads (e # s)) = 
-                      (th \<in> readys (s) \<or> th \<notin> threads (s))" 
-            by (simp add:threads.simps)
-          with eq_cnp eq_cnv eq_cncs ih not_in
-          have ?thesis by simp
-        } moreover {
-          assume eq_th: "th = thread"
-          with not_in ih have " cntP s th  = cntV s th + cntCS s th" by simp
-          moreover from eq_th and eq_readys have "th \<in> readys (e#s)" by simp
-          moreover note eq_cnp eq_cnv eq_cncs
-          ultimately have ?thesis by auto
-        } ultimately show ?thesis by blast
-      qed
-    next
-      case (thread_exit thread)
-      assume eq_e: "e = Exit thread" 
-      and is_runing: "thread \<in> runing s"
-      and no_hold: "holdents s thread = {}"
-      from eq_e have eq_cnp: "cntP (e#s) th = cntP s th" by (simp add:cntP_def count_def)
-      from eq_e have eq_cnv: "cntV (e#s) th = cntV s th" by (simp add:cntV_def count_def)
-      have eq_cncs: "cntCS (e#s) th = cntCS s th"
-        unfolding cntCS_def holdents_def
-        by (simp add:depend_exit_unchanged eq_e)
-      { assume "th \<noteq> thread"
-        with eq_e
-        have "(th \<in> readys (e # s) \<or> th \<notin> threads (e # s)) = 
-          (th \<in> readys (s) \<or> th \<notin> threads (s))" 
-          apply (simp add:threads.simps readys_def)
-          apply (subst s_waiting_def)
-          apply (subst (1 2) wq_def)
-          apply (simp add:Let_def)
-          apply (subst s_waiting_def, simp)
-          by (fold wq_def, simp)
-        with eq_cnp eq_cnv eq_cncs ih
-        have ?thesis by simp
-      } moreover {
-        assume eq_th: "th = thread"
-        with ih is_runing have " cntP s th = cntV s th + cntCS s th" 
-          by (simp add:runing_def)
-        moreover from eq_th eq_e have "th \<notin> threads (e#s)"
-          by simp
-        moreover note eq_cnp eq_cnv eq_cncs
-        ultimately have ?thesis by auto
-      } ultimately show ?thesis by blast
-    next
-      case (thread_P thread cs)
-      assume eq_e: "e = P thread cs"
-        and is_runing: "thread \<in> runing s"
-        and no_dep: "(Cs cs, Th thread) \<notin> (depend s)\<^sup>+"
-      from prems have vtp: "vt step (P thread cs#s)" by auto
-      show ?thesis 
-      proof -
-        { have hh: "\<And> A B C. (B = C) \<Longrightarrow> (A \<and> B) = (A \<and> C)" by blast
-          assume neq_th: "th \<noteq> thread"
-          with eq_e
-          have eq_readys: "(th \<in> readys (e#s)) = (th \<in> readys (s))"
-            apply (simp add:readys_def s_waiting_def wq_def Let_def)
-            apply (rule_tac hh, clarify)
-            apply (intro iffI allI, clarify)
-            apply (erule_tac x = csa in allE, auto)
-            apply (subgoal_tac "waiting_queue (schs s) cs \<noteq> []", auto)
-            apply (erule_tac x = cs in allE, auto)
-            by (case_tac "(waiting_queue (schs s) cs)", auto)
-          moreover from neq_th eq_e have "cntCS (e # s) th = cntCS s th"
-            apply (simp add:cntCS_def holdents_def)
-            by (unfold  step_depend_p [OF vtp], auto)
-          moreover from eq_e neq_th have "cntP (e # s) th = cntP s th"
-            by (simp add:cntP_def count_def)
-          moreover from eq_e neq_th have "cntV (e#s) th = cntV s th"
-            by (simp add:cntV_def count_def)
-          moreover from eq_e neq_th have "threads (e#s) = threads s" by simp
-          moreover note ih [of th] 
-          ultimately have ?thesis by simp
-        } moreover {
-          assume eq_th: "th = thread"
-          have ?thesis
-          proof -
-            from eq_e eq_th have eq_cnp: "cntP (e # s) th  = 1 + (cntP s th)" 
-              by (simp add:cntP_def count_def)
-            from eq_e eq_th have eq_cnv: "cntV (e#s) th = cntV s th"
-              by (simp add:cntV_def count_def)
-            show ?thesis
-            proof (cases "wq s cs = []")
-              case True
-              with is_runing
-              have "th \<in> readys (e#s)"
-                apply (unfold eq_e wq_def, unfold readys_def s_depend_def)
-                apply (simp add: wq_def[symmetric] runing_def eq_th s_waiting_def)
-                by (auto simp:readys_def wq_def Let_def s_waiting_def wq_def)
-              moreover have "cntCS (e # s) th = 1 + cntCS s th"
-              proof -
-                have "card {csa. csa = cs \<or> (Cs csa, Th thread) \<in> depend s} =
-                  Suc (card {cs. (Cs cs, Th thread) \<in> depend s})" (is "card ?L = Suc (card ?R)")
-                proof -
-                  have "?L = insert cs ?R" by auto
-                  moreover have "card \<dots> = Suc (card (?R - {cs}))" 
-                  proof(rule card_insert)
-                    from finite_holding [OF vt, of thread]
-                    show " finite {cs. (Cs cs, Th thread) \<in> depend s}"
-                      by (unfold holdents_def, simp)
-                  qed
-                  moreover have "?R - {cs} = ?R"
-                  proof -
-                    have "cs \<notin> ?R"
-                    proof
-                      assume "cs \<in> {cs. (Cs cs, Th thread) \<in> depend s}"
-                      with no_dep show False by auto
-                    qed
-                    thus ?thesis by auto
-                  qed
-                  ultimately show ?thesis by auto
-                qed
-                thus ?thesis
-                  apply (unfold eq_e eq_th cntCS_def)
-                  apply (simp add: holdents_def)
-                  by (unfold step_depend_p [OF vtp], auto simp:True)
-              qed
-              moreover from is_runing have "th \<in> readys s"
-                by (simp add:runing_def eq_th)
-              moreover note eq_cnp eq_cnv ih [of th]
-              ultimately show ?thesis by auto
-            next
-              case False
-              have eq_wq: "wq (e#s) cs = wq s cs @ [th]"
-                    by (unfold eq_th eq_e wq_def, auto simp:Let_def)
-              have "th \<notin> readys (e#s)"
-              proof
-                assume "th \<in> readys (e#s)"
-                hence "\<forall>cs. \<not> waiting (e # s) th cs" by (simp add:readys_def)
-                from this[rule_format, of cs] have " \<not> waiting (e # s) th cs" .
-                hence "th \<in> set (wq (e#s) cs) \<Longrightarrow> th = hd (wq (e#s) cs)" 
-                  by (simp add:s_waiting_def)
-                moreover from eq_wq have "th \<in> set (wq (e#s) cs)" by auto
-                ultimately have "th = hd (wq (e#s) cs)" by blast
-                with eq_wq have "th = hd (wq s cs @ [th])" by simp
-                hence "th = hd (wq s cs)" using False by auto
-                with False eq_wq wq_distinct [OF vtp, of cs]
-                show False by (fold eq_e, auto)
-              qed
-              moreover from is_runing have "th \<in> threads (e#s)" 
-                by (unfold eq_e, auto simp:runing_def readys_def eq_th)
-              moreover have "cntCS (e # s) th = cntCS s th"
-                apply (unfold cntCS_def holdents_def eq_e step_depend_p[OF vtp])
-                by (auto simp:False)
-              moreover note eq_cnp eq_cnv ih[of th]
-              moreover from is_runing have "th \<in> readys s"
-                by (simp add:runing_def eq_th)
-              ultimately show ?thesis by auto
-            qed
-          qed
-        } ultimately show ?thesis by blast
-      qed
-    next
-      case (thread_V thread cs)
-      from prems have vtv: "vt step (V thread cs # s)" by auto
-      assume eq_e: "e = V thread cs"
-        and is_runing: "thread \<in> runing s"
-        and hold: "holding s thread cs"
-      from hold obtain rest 
-        where eq_wq: "wq s cs = thread # rest"
-        by (case_tac "wq s cs", auto simp:s_holding_def)
-      have eq_threads: "threads (e#s) = threads s" by (simp add: eq_e)
-      show ?thesis
-      proof -
-        { assume eq_th: "th = thread"
-          from eq_th have eq_cnp: "cntP (e # s) th = cntP s th"
-            by (unfold eq_e, simp add:cntP_def count_def)
-          moreover from eq_th have eq_cnv: "cntV (e#s) th = 1 + cntV s th"
-            by (unfold eq_e, simp add:cntV_def count_def)
-          moreover from cntCS_v_dec [OF vtv] 
-          have "cntCS (e # s) thread + 1 = cntCS s thread"
-            by (simp add:eq_e)
-          moreover from is_runing have rd_before: "thread \<in> readys s"
-            by (unfold runing_def, simp)
-          moreover have "thread \<in> readys (e # s)"
-          proof -
-            from is_runing
-            have "thread \<in> threads (e#s)" 
-              by (unfold eq_e, auto simp:runing_def readys_def)
-            moreover have "\<forall> cs1. \<not> waiting (e#s) thread cs1"
-            proof
-              fix cs1
-              { assume eq_cs: "cs1 = cs" 
-                have "\<not> waiting (e # s) thread cs1"
-                proof -
-                  have "thread \<notin> set (wq (e#s) cs1)"
-                  proof(cases "lsp (cp s) rest")
-                    fix l m r 
-                    assume h: "lsp (cp s) rest = (l, m, r)"
-                    show ?thesis
-                    proof(cases "m")
-                      case Nil
-                      from wq_v_eq_nil [OF eq_wq] h Nil eq_e
-                      have " wq (e # s) cs = []" by auto
-                      thus ?thesis using eq_cs by auto
-                    next
-                      case (Cons th' l')
-                      from lsp_mid_length [OF h] and Cons h
-                      have eqh: "lsp (cp s) rest = (l, [th'], r)" by auto
-                      from wq_v_eq [OF eq_wq this]
-                      have "wq (V thread cs # s) cs = th' # l @ r" .
-                      moreover from lsp_set_eq [OF eqh]
-                      have "set rest = set \<dots>" by auto
-                      moreover have "thread \<notin> set rest"
-                      proof -
-                        from wq_distinct [OF step_back_vt[OF vtv], of cs]
-                        and eq_wq show ?thesis by auto
-                      qed
-                      moreover note eq_e eq_cs
-                      ultimately show ?thesis by simp
-                    qed
-                  qed
-                  thus ?thesis by (simp add:s_waiting_def)
-                qed
-              } moreover {
-                assume neq_cs: "cs1 \<noteq> cs"
-                  have "\<not> waiting (e # s) thread cs1" 
-                  proof -
-                    from wq_v_neq [OF neq_cs[symmetric]]
-                    have "wq (V thread cs # s) cs1 = wq s cs1" .
-                    moreover have "\<not> waiting s thread cs1" 
-                    proof -
-                      from runing_ready and is_runing
-                      have "thread \<in> readys s" by auto
-                      thus ?thesis by (simp add:readys_def)
-                    qed
-                    ultimately show ?thesis 
-                      by (auto simp:s_waiting_def eq_e)
-                  qed
-              } ultimately show "\<not> waiting (e # s) thread cs1" by blast
-            qed
-            ultimately show ?thesis by (simp add:readys_def)
-          qed
-          moreover note eq_th ih
-          ultimately have ?thesis by auto
-        } moreover {
-          assume neq_th: "th \<noteq> thread"
-          from neq_th eq_e have eq_cnp: "cntP (e # s) th = cntP s th" 
-            by (simp add:cntP_def count_def)
-          from neq_th eq_e have eq_cnv: "cntV (e # s) th = cntV s th" 
-            by (simp add:cntV_def count_def)
-          have ?thesis
-          proof(cases "th \<in> set rest")
-            case False
-            have "(th \<in> readys (e # s)) = (th \<in> readys s)"
-              by(unfold eq_e, rule readys_v_eq [OF neq_th eq_wq False])
-            moreover have "cntCS (e#s) th = cntCS s th"
-              by(unfold eq_e, rule cntCS_v_eq [OF neq_th eq_wq False vtv]) 
-            moreover note ih eq_cnp eq_cnv eq_threads
-            ultimately show ?thesis by auto
-          next
-            case True
-            obtain l m r where eq_lsp: "lsp (cp s) rest = (l, m, r)" 
-              by (cases "lsp (cp s) rest", auto)
-            with True have "m \<noteq> []" by  (auto dest:lsp_mid_nil)
-            with eq_lsp obtain th' where eq_lsp: "lsp (cp s) rest = (l, [th'], r)"
-              by (case_tac m, auto dest:lsp_mid_length)
-            show ?thesis
-            proof(cases "th = th'")
-              case False
-              have "(th \<in> readys (e # s)) = (th \<in> readys s)"
-                by (unfold eq_e, rule readys_v_eq_1 [OF neq_th eq_wq eq_lsp False])
-              moreover have "cntCS (e#s) th = cntCS s th" 
-                by (unfold eq_e, rule cntCS_v_eq_1[OF neq_th eq_wq eq_lsp False vtv])
-              moreover note ih eq_cnp eq_cnv eq_threads
-              ultimately show ?thesis by auto
-            next
-              case True
-              have "th \<in> readys (e # s)"
-                by (unfold eq_e, rule readys_v_eq_2 [OF neq_th eq_wq eq_lsp True vt])
-              moreover have "cntP s th = cntV s th + cntCS s th + 1"
-              proof -
-                have "th \<notin> readys s" 
-                proof -
-                  from True eq_wq lsp_set_eq [OF eq_lsp] neq_th
-                  show ?thesis
-                    apply (unfold readys_def s_waiting_def, auto)
-                    by (rule_tac x = cs in exI, auto)
-                qed
-                moreover have "th \<in> threads s"
-                proof -
-                  from True eq_wq lsp_set_eq [OF eq_lsp] neq_th
-                  have "th \<in> set (wq s cs)" by simp
-                  from wq_threads [OF step_back_vt[OF vtv] this] 
-                  show ?thesis .
-                qed
-                ultimately show ?thesis using ih by auto
-              qed
-              moreover have "cntCS (e # s) th = 1 + cntCS s th"
-                by (unfold eq_e, rule cntCS_v_eq_2 [OF neq_th eq_wq eq_lsp True vtv])
-              moreover note eq_cnp eq_cnv
-              ultimately show ?thesis by simp
-            qed
-          qed
-        } ultimately show ?thesis by blast
-      qed
-    next
-      case (thread_set thread prio)
-      assume eq_e: "e = Set thread prio"
-        and is_runing: "thread \<in> runing s"
-      show ?thesis
-      proof -
-        from eq_e have eq_cnp: "cntP (e#s) th = cntP s th" by (simp add:cntP_def count_def)
-        from eq_e have eq_cnv: "cntV (e#s) th = cntV s th" by (simp add:cntV_def count_def)
-        have eq_cncs: "cntCS (e#s) th = cntCS s th"
-          unfolding cntCS_def holdents_def
-          by (simp add:depend_set_unchanged eq_e)
-        from eq_e have eq_readys: "readys (e#s) = readys s" 
-          by (simp add:readys_def cs_waiting_def s_waiting_def wq_def,
-                  auto simp:Let_def)
-        { assume "th \<noteq> thread"
-          with eq_readys eq_e
-          have "(th \<in> readys (e # s) \<or> th \<notin> threads (e # s)) = 
-                      (th \<in> readys (s) \<or> th \<notin> threads (s))" 
-            by (simp add:threads.simps)
-          with eq_cnp eq_cnv eq_cncs ih is_runing
-          have ?thesis by simp
-        } moreover {
-          assume eq_th: "th = thread"
-          with is_runing ih have " cntP s th  = cntV s th + cntCS s th" 
-            by (unfold runing_def, auto)
-          moreover from eq_th and eq_readys is_runing have "th \<in> readys (e#s)"
-            by (simp add:runing_def)
-          moreover note eq_cnp eq_cnv eq_cncs
-          ultimately have ?thesis by auto
-        } ultimately show ?thesis by blast
-      qed   
-    qed
-  next
-    case vt_nil
-    show ?case 
-      by (unfold cntP_def cntV_def cntCS_def, 
-        auto simp:count_def holdents_def s_depend_def wq_def cs_holding_def)
-  qed
-qed
-
-lemma not_thread_cncs:
-  fixes th s
-  assumes vt: "vt step s"
-  and not_in: "th \<notin> threads s" 
-  shows "cntCS s th = 0"
-proof -
-  from vt not_in show ?thesis
-  proof(induct arbitrary:th)
-    case (vt_cons s e th)
-    assume vt: "vt step s"
-      and ih: "\<And>th. th \<notin> threads s \<Longrightarrow> cntCS s th = 0"
-      and stp: "step s e"
-      and not_in: "th \<notin> threads (e # s)"
-    from stp show ?case
-    proof(cases)
-      case (thread_create prio max_prio thread)
-      assume eq_e: "e = Create thread prio"
-        and not_in': "thread \<notin> threads s"
-      have "cntCS (e # s) th = cntCS s th"
-        apply (unfold eq_e cntCS_def holdents_def)
-        by (simp add:depend_create_unchanged)
-      moreover have "th \<notin> threads s" 
-      proof -
-        from not_in eq_e show ?thesis by simp
-      qed
-      moreover note ih ultimately show ?thesis by auto
-    next
-      case (thread_exit thread)
-      assume eq_e: "e = Exit thread"
-      and nh: "holdents s thread = {}"
-      have eq_cns: "cntCS (e # s) th = cntCS s th"
-        apply (unfold eq_e cntCS_def holdents_def)
-        by (simp add:depend_exit_unchanged)
-      show ?thesis
-      proof(cases "th = thread")
-        case True
-        have "cntCS s th = 0" by (unfold cntCS_def, auto simp:nh True)
-        with eq_cns show ?thesis by simp
-      next
-        case False
-        with not_in and eq_e
-        have "th \<notin> threads s" by simp
-        from ih[OF this] and eq_cns show ?thesis by simp
-      qed
-    next
-      case (thread_P thread cs)
-      assume eq_e: "e = P thread cs"
-      and is_runing: "thread \<in> runing s"
-      from prems have vtp: "vt step (P thread cs#s)" by auto
-      have neq_th: "th \<noteq> thread" 
-      proof -
-        from not_in eq_e have "th \<notin> threads s" by simp
-        moreover from is_runing have "thread \<in> threads s"
-          by (simp add:runing_def readys_def)
-        ultimately show ?thesis by auto
-      qed
-      hence "cntCS (e # s) th  = cntCS s th "
-        apply (unfold cntCS_def holdents_def eq_e)
-        by (unfold step_depend_p[OF vtp], auto)
-      moreover have "cntCS s th = 0"
-      proof(rule ih)
-        from not_in eq_e show "th \<notin> threads s" by simp
-      qed
-      ultimately show ?thesis by simp
-    next
-      case (thread_V thread cs)
-      assume eq_e: "e = V thread cs"
-        and is_runing: "thread \<in> runing s"
-        and hold: "holding s thread cs"
-      have neq_th: "th \<noteq> thread" 
-      proof -
-        from not_in eq_e have "th \<notin> threads s" by simp
-        moreover from is_runing have "thread \<in> threads s"
-          by (simp add:runing_def readys_def)
-        ultimately show ?thesis by auto
-      qed
-      from prems have vtv: "vt step (V thread cs#s)" by auto
-      from hold obtain rest 
-        where eq_wq: "wq s cs = thread # rest"
-        by (case_tac "wq s cs", auto simp:s_holding_def)
-      have "cntCS (e # s) th  = cntCS s th"
-      proof(unfold eq_e, rule cntCS_v_eq [OF neq_th eq_wq _ vtv])
-        show "th \<notin> set rest" 
-        proof
-          assume "th \<in> set rest"
-          with eq_wq have "th \<in> set (wq s cs)" by simp
-          from wq_threads [OF vt this] eq_e not_in 
-          show False by simp
-        qed
-      qed
-      moreover have "cntCS s th = 0"
-      proof(rule ih)
-        from not_in eq_e show "th \<notin> threads s" by simp
-      qed
-      ultimately show ?thesis by simp
-    next
-      case (thread_set thread prio)
-      print_facts
-      assume eq_e: "e = Set thread prio"
-        and is_runing: "thread \<in> runing s"
-      from not_in and eq_e have "th \<notin> threads s" by auto
-      from ih [OF this] and eq_e
-      show ?thesis 
-        apply (unfold eq_e cntCS_def holdents_def)
-        by (simp add:depend_set_unchanged)
-    qed
-    next
-      case vt_nil
-      show ?case
-      by (unfold cntCS_def, 
-        auto simp:count_def holdents_def s_depend_def wq_def cs_holding_def)
-  qed
-qed
-
-lemma eq_waiting: "waiting (wq (s::state)) th cs = waiting s th cs"
-  by (auto simp:s_waiting_def cs_waiting_def)
-
-lemma dm_depend_threads:
-  fixes th s
-  assumes vt: "vt step s"
-  and in_dom: "(Th th) \<in> Domain (depend s)"
-  shows "th \<in> threads s"
-proof -
-  from in_dom obtain n where "(Th th, n) \<in> depend s" by auto
-  moreover from depend_target_th[OF this] obtain cs where "n = Cs cs" by auto
-  ultimately have "(Th th, Cs cs) \<in> depend s" by simp
-  hence "th \<in> set (wq s cs)"
-    by (unfold s_depend_def, auto simp:cs_waiting_def)
-  from wq_threads [OF vt this] show ?thesis .
-qed
-
-lemma cp_eq_cpreced: "cp s th = cpreced s (wq s) th"
-proof(unfold cp_def wq_def, induct s)
-  case (Cons e s')
-  show ?case
-    by (auto simp:Let_def)
-next
-  case Nil
-  show ?case by (auto simp:Let_def)
-qed
-
-fun the_th :: "node \<Rightarrow> thread"
-  where "the_th (Th th) = th"
-
-lemma runing_unique:
-  fixes th1 th2 s
-  assumes vt: "vt step s"
-  and runing_1: "th1 \<in> runing s"
-  and runing_2: "th2 \<in> runing s"
-  shows "th1 = th2"
-proof -
-  from runing_1 and runing_2 have "cp s th1 = cp s th2"
-    by (unfold runing_def, simp)
-  hence eq_max: "Max ((\<lambda>th. preced th s) ` ({th1} \<union> dependents (wq s) th1)) =
-                 Max ((\<lambda>th. preced th s) ` ({th2} \<union> dependents (wq s) th2))"
-    (is "Max (?f ` ?A) = Max (?f ` ?B)")
-    by (unfold cp_eq_cpreced cpreced_def)
-  obtain th1' where th1_in: "th1' \<in> ?A" and eq_f_th1: "?f th1' = Max (?f ` ?A)"
-  proof -
-    have h1: "finite (?f ` ?A)"
-    proof -
-      have "finite ?A" 
-      proof -
-        have "finite (dependents (wq s) th1)"
-        proof-
-          have "finite {th'. (Th th', Th th1) \<in> (depend (wq s))\<^sup>+}"
-          proof -
-            let ?F = "\<lambda> (x, y). the_th x"
-            have "{th'. (Th th', Th th1) \<in> (depend (wq s))\<^sup>+} \<subseteq> ?F ` ((depend (wq s))\<^sup>+)"
-              apply (auto simp:image_def)
-              by (rule_tac x = "(Th x, Th th1)" in bexI, auto)
-            moreover have "finite \<dots>"
-            proof -
-              from finite_depend[OF vt] have "finite (depend s)" .
-              hence "finite ((depend (wq s))\<^sup>+)"
-                apply (unfold finite_trancl)
-                by (auto simp: s_depend_def cs_depend_def wq_def)
-              thus ?thesis by auto
-            qed
-            ultimately show ?thesis by (auto intro:finite_subset)
-          qed
-          thus ?thesis by (simp add:cs_dependents_def)
-        qed
-        thus ?thesis by simp
-      qed
-      thus ?thesis by auto
-    qed
-    moreover have h2: "(?f ` ?A) \<noteq> {}"
-    proof -
-      have "?A \<noteq> {}" by simp
-      thus ?thesis by simp
-    qed
-    from Max_in [OF h1 h2]
-    have "Max (?f ` ?A) \<in> (?f ` ?A)" .
-    thus ?thesis by (auto intro:that)
-  qed
-  obtain th2' where th2_in: "th2' \<in> ?B" and eq_f_th2: "?f th2' = Max (?f ` ?B)"
-  proof -
-    have h1: "finite (?f ` ?B)"
-    proof -
-      have "finite ?B" 
-      proof -
-        have "finite (dependents (wq s) th2)"
-        proof-
-          have "finite {th'. (Th th', Th th2) \<in> (depend (wq s))\<^sup>+}"
-          proof -
-            let ?F = "\<lambda> (x, y). the_th x"
-            have "{th'. (Th th', Th th2) \<in> (depend (wq s))\<^sup>+} \<subseteq> ?F ` ((depend (wq s))\<^sup>+)"
-              apply (auto simp:image_def)
-              by (rule_tac x = "(Th x, Th th2)" in bexI, auto)
-            moreover have "finite \<dots>"
-            proof -
-              from finite_depend[OF vt] have "finite (depend s)" .
-              hence "finite ((depend (wq s))\<^sup>+)"
-                apply (unfold finite_trancl)
-                by (auto simp: s_depend_def cs_depend_def wq_def)
-              thus ?thesis by auto
-            qed
-            ultimately show ?thesis by (auto intro:finite_subset)
-          qed
-          thus ?thesis by (simp add:cs_dependents_def)
-        qed
-        thus ?thesis by simp
-      qed
-      thus ?thesis by auto
-    qed
-    moreover have h2: "(?f ` ?B) \<noteq> {}"
-    proof -
-      have "?B \<noteq> {}" by simp
-      thus ?thesis by simp
-    qed
-    from Max_in [OF h1 h2]
-    have "Max (?f ` ?B) \<in> (?f ` ?B)" .
-    thus ?thesis by (auto intro:that)
-  qed
-  from eq_f_th1 eq_f_th2 eq_max 
-  have eq_preced: "preced th1' s = preced th2' s" by auto
-  hence eq_th12: "th1' = th2'"
-  proof (rule preced_unique)
-    from th1_in have "th1' = th1 \<or> (th1' \<in> dependents (wq s) th1)" by simp
-    thus "th1' \<in> threads s"
-    proof
-      assume "th1' \<in> dependents (wq s) th1"
-      hence "(Th th1') \<in> Domain ((depend s)^+)"
-        apply (unfold cs_dependents_def cs_depend_def s_depend_def)
-        by (auto simp:Domain_def)
-      hence "(Th th1') \<in> Domain (depend s)" by (simp add:trancl_domain)
-      from dm_depend_threads[OF vt this] show ?thesis .
-    next
-      assume "th1' = th1"
-      with runing_1 show ?thesis
-        by (unfold runing_def readys_def, auto)
-    qed
-  next
-    from th2_in have "th2' = th2 \<or> (th2' \<in> dependents (wq s) th2)" by simp
-    thus "th2' \<in> threads s"
-    proof
-      assume "th2' \<in> dependents (wq s) th2"
-      hence "(Th th2') \<in> Domain ((depend s)^+)"
-        apply (unfold cs_dependents_def cs_depend_def s_depend_def)
-        by (auto simp:Domain_def)
-      hence "(Th th2') \<in> Domain (depend s)" by (simp add:trancl_domain)
-      from dm_depend_threads[OF vt this] show ?thesis .
-    next
-      assume "th2' = th2"
-      with runing_2 show ?thesis
-        by (unfold runing_def readys_def, auto)
-    qed
-  qed
-  from th1_in have "th1' = th1 \<or> th1' \<in> dependents (wq s) th1" by simp
-  thus ?thesis
-  proof
-    assume eq_th': "th1' = th1"
-    from th2_in have "th2' = th2 \<or> th2' \<in> dependents (wq s) th2" by simp
-    thus ?thesis
-    proof
-      assume "th2' = th2" thus ?thesis using eq_th' eq_th12 by simp
-    next
-      assume "th2' \<in> dependents (wq s) th2"
-      with eq_th12 eq_th' have "th1 \<in> dependents (wq s) th2" by simp
-      hence "(Th th1, Th th2) \<in> (depend s)^+"
-        by (unfold cs_dependents_def s_depend_def cs_depend_def, simp)
-      hence "Th th1 \<in> Domain ((depend s)^+)" using Domain_def [of "(depend s)^+"]
-        by auto
-      hence "Th th1 \<in> Domain (depend s)" by (simp add:trancl_domain)
-      then obtain n where d: "(Th th1, n) \<in> depend s" by (auto simp:Domain_def)
-      from depend_target_th [OF this]
-      obtain cs' where "n = Cs cs'" by auto
-      with d have "(Th th1, Cs cs') \<in> depend s" by simp
-      with runing_1 have "False"
-        apply (unfold runing_def readys_def s_depend_def)
-        by (auto simp:eq_waiting)
-      thus ?thesis by simp
-    qed
-  next
-    assume th1'_in: "th1' \<in> dependents (wq s) th1"
-    from th2_in have "th2' = th2 \<or> th2' \<in> dependents (wq s) th2" by simp
-    thus ?thesis 
-    proof
-      assume "th2' = th2"
-      with th1'_in eq_th12 have "th2 \<in> dependents (wq s) th1" by simp
-      hence "(Th th2, Th th1) \<in> (depend s)^+"
-        by (unfold cs_dependents_def s_depend_def cs_depend_def, simp)
-      hence "Th th2 \<in> Domain ((depend s)^+)" using Domain_def [of "(depend s)^+"]
-        by auto
-      hence "Th th2 \<in> Domain (depend s)" by (simp add:trancl_domain)
-      then obtain n where d: "(Th th2, n) \<in> depend s" by (auto simp:Domain_def)
-      from depend_target_th [OF this]
-      obtain cs' where "n = Cs cs'" by auto
-      with d have "(Th th2, Cs cs') \<in> depend s" by simp
-      with runing_2 have "False"
-        apply (unfold runing_def readys_def s_depend_def)
-        by (auto simp:eq_waiting)
-      thus ?thesis by simp
-    next
-      assume "th2' \<in> dependents (wq s) th2"
-      with eq_th12 have "th1' \<in> dependents (wq s) th2" by simp
-      hence h1: "(Th th1', Th th2) \<in> (depend s)^+"
-        by (unfold cs_dependents_def s_depend_def cs_depend_def, simp)
-      from th1'_in have h2: "(Th th1', Th th1) \<in> (depend s)^+"
-        by (unfold cs_dependents_def s_depend_def cs_depend_def, simp)
-      show ?thesis
-      proof(rule dchain_unique[OF vt h1 _ h2, symmetric])
-        from runing_1 show "th1 \<in> readys s" by (simp add:runing_def)
-        from runing_2 show "th2 \<in> readys s" by (simp add:runing_def) 
-      qed
-    qed
-  qed
-qed
-
-lemma create_pre:
-  assumes stp: "step s e"
-  and not_in: "th \<notin> threads s"
-  and is_in: "th \<in> threads (e#s)"
-  obtains prio where "e = Create th prio"
-proof -
-  from assms  
-  show ?thesis
-  proof(cases)
-    case (thread_create prio max_prio thread)
-    with is_in not_in have "e = Create th prio" by simp
-    from that[OF this] show ?thesis .
-  next
-    case (thread_exit thread)
-    with assms show ?thesis by (auto intro!:that)
-  next
-    case (thread_P thread)
-    with assms show ?thesis by (auto intro!:that)
-  next
-    case (thread_V thread)
-    with assms show ?thesis by (auto intro!:that)
-  next 
-    case (thread_set thread)
-    with assms show ?thesis by (auto intro!:that)
-  qed
-qed
-
-lemma length_down_to_in: 
-  assumes le_ij: "i \<le> j"
-    and le_js: "j \<le> length s"
-  shows "length (down_to j i s) = j - i"
-proof -
-  have "length (down_to j i s) = length (from_to i j (rev s))"
-    by (unfold down_to_def, auto)
-  also have "\<dots> = j - i"
-  proof(rule length_from_to_in[OF le_ij])
-    from le_js show "j \<le> length (rev s)" by simp
-  qed
-  finally show ?thesis .
-qed
-
-
-lemma moment_head: 
-  assumes le_it: "Suc i \<le> length t"
-  obtains e where "moment (Suc i) t = e#moment i t"
-proof -
-  have "i \<le> Suc i" by simp
-  from length_down_to_in [OF this le_it]
-  have "length (down_to (Suc i) i t) = 1" by auto
-  then obtain e where "down_to (Suc i) i t = [e]"
-    apply (cases "(down_to (Suc i) i t)") by auto
-  moreover have "down_to (Suc i) 0 t = down_to (Suc i) i t @ down_to i 0 t"
-    by (rule down_to_conc[symmetric], auto)
-  ultimately have eq_me: "moment (Suc i) t = e#(moment i t)"
-    by (auto simp:down_to_moment)
-  from that [OF this] show ?thesis .
-qed
-
-lemma cnp_cnv_eq:
-  fixes th s
-  assumes "vt step s"
-  and "th \<notin> threads s"
-  shows "cntP s th = cntV s th"
-proof -
-  from assms show ?thesis
-  proof(induct)
-    case (vt_cons s e)
-    have ih: "th \<notin> threads s \<Longrightarrow> cntP s th = cntV s th" by fact
-    have not_in: "th \<notin> threads (e # s)" by fact
-    have "step s e" by fact
-    thus ?case proof(cases)
-      case (thread_create prio max_prio thread)
-      assume eq_e: "e = Create thread prio"
-      hence "thread \<in> threads (e#s)" by simp
-      with not_in and eq_e have "th \<notin> threads s" by auto
-      from ih [OF this] show ?thesis using eq_e
-        by (auto simp:cntP_def cntV_def count_def)
-    next
-      case (thread_exit thread)
-      assume eq_e: "e = Exit thread"
-        and not_holding: "holdents s thread = {}"
-      have vt_s: "vt step s" by fact
-      from finite_holding[OF vt_s] have "finite (holdents s thread)" .
-      with not_holding have "cntCS s thread = 0" by (unfold cntCS_def, auto)
-      moreover have "thread \<in> readys s" using thread_exit by (auto simp:runing_def)
-      moreover note cnp_cnv_cncs[OF vt_s, of thread]
-      ultimately have eq_thread: "cntP s thread = cntV s thread" by auto
-      show ?thesis
-      proof(cases "th = thread")
-        case True
-        with eq_thread eq_e show ?thesis 
-          by (auto simp:cntP_def cntV_def count_def)
-      next
-        case False
-        with not_in and eq_e have "th \<notin> threads s" by simp
-        from ih[OF this] and eq_e show ?thesis 
-           by (auto simp:cntP_def cntV_def count_def)
-      qed
-    next
-      case (thread_P thread cs)
-      assume eq_e: "e = P thread cs"
-      have "thread \<in> runing s" by fact
-      with not_in eq_e have neq_th: "thread \<noteq> th" 
-        by (auto simp:runing_def readys_def)
-      from not_in eq_e have "th \<notin> threads s" by simp
-      from ih[OF this] and neq_th and eq_e show ?thesis
-        by (auto simp:cntP_def cntV_def count_def)
-    next
-      case (thread_V thread cs)
-      assume eq_e: "e = V thread cs"
-      have "thread \<in> runing s" by fact
-      with not_in eq_e have neq_th: "thread \<noteq> th" 
-        by (auto simp:runing_def readys_def)
-      from not_in eq_e have "th \<notin> threads s" by simp
-      from ih[OF this] and neq_th and eq_e show ?thesis
-        by (auto simp:cntP_def cntV_def count_def)
-    next
-      case (thread_set thread prio)
-      assume eq_e: "e = Set thread prio"
-        and "thread \<in> runing s"
-      hence "thread \<in> threads (e#s)" 
-        by (simp add:runing_def readys_def)
-      with not_in and eq_e have "th \<notin> threads s" by auto
-      from ih [OF this] show ?thesis using eq_e
-        by (auto simp:cntP_def cntV_def count_def)  
-    qed
-  next
-    case vt_nil
-    show ?case by (auto simp:cntP_def cntV_def count_def)
-  qed
-qed
-
-lemma eq_depend: 
-  "depend (wq s) = depend s"
-by (unfold cs_depend_def s_depend_def, auto)
-
-lemma count_eq_dependents:
-  assumes vt: "vt step s"
-  and eq_pv: "cntP s th = cntV s th"
-  shows "dependents (wq s) th = {}"
-proof -
-  from cnp_cnv_cncs[OF vt] and eq_pv
-  have "cntCS s th = 0" 
-    by (auto split:if_splits)
-  moreover have "finite {cs. (Cs cs, Th th) \<in> depend s}"
-  proof -
-    from finite_holding[OF vt, of th] show ?thesis
-      by (simp add:holdents_def)
-  qed
-  ultimately have h: "{cs. (Cs cs, Th th) \<in> depend s} = {}"
-    by (unfold cntCS_def holdents_def cs_dependents_def, auto)
-  show ?thesis
-  proof(unfold cs_dependents_def)
-    { assume "{th'. (Th th', Th th) \<in> (depend (wq s))\<^sup>+} \<noteq> {}"
-      then obtain th' where "(Th th', Th th) \<in> (depend (wq s))\<^sup>+" by auto
-      hence "False"
-      proof(cases)
-        assume "(Th th', Th th) \<in> depend (wq s)"
-        thus "False" by (auto simp:cs_depend_def)
-      next
-        fix c
-        assume "(c, Th th) \<in> depend (wq s)"
-        with h and eq_depend show "False"
-          by (cases c, auto simp:cs_depend_def)
-      qed
-    } thus "{th'. (Th th', Th th) \<in> (depend (wq s))\<^sup>+} = {}" by auto
-  qed
-qed
-
-lemma dependents_threads:
-  fixes s th
-  assumes vt: "vt step s"
-  shows "dependents (wq s) th \<subseteq> threads s"
-proof
-  { fix th th'
-    assume h: "th \<in> {th'a. (Th th'a, Th th') \<in> (depend (wq s))\<^sup>+}"
-    have "Th th \<in> Domain (depend s)"
-    proof -
-      from h obtain th' where "(Th th, Th th') \<in> (depend (wq s))\<^sup>+" by auto
-      hence "(Th th) \<in> Domain ( (depend (wq s))\<^sup>+)" by (auto simp:Domain_def)
-      with trancl_domain have "(Th th) \<in> Domain (depend (wq s))" by simp
-      thus ?thesis using eq_depend by simp
-    qed
-    from dm_depend_threads[OF vt this]
-    have "th \<in> threads s" .
-  } note hh = this
-  fix th1 
-  assume "th1 \<in> dependents (wq s) th"
-  hence "th1 \<in> {th'a. (Th th'a, Th th) \<in> (depend (wq s))\<^sup>+}"
-    by (unfold cs_dependents_def, simp)
-  from hh [OF this] show "th1 \<in> threads s" .
-qed
-
-lemma finite_threads:
-  assumes vt: "vt step s"
-  shows "finite (threads s)"
-proof -
-  from vt show ?thesis
-  proof(induct)
-    case (vt_cons s e)
-    assume vt: "vt step s"
-    and step: "step s e"
-    and ih: "finite (threads s)"
-    from step
-    show ?case
-    proof(cases)
-      case (thread_create prio max_prio thread)
-      assume eq_e: "e = Create thread prio"
-      with ih
-      show ?thesis by (unfold eq_e, auto)
-    next
-      case (thread_exit thread)
-      assume eq_e: "e = Exit thread"
-      with ih show ?thesis 
-        by (unfold eq_e, auto)
-    next
-      case (thread_P thread cs)
-      assume eq_e: "e = P thread cs"
-      with ih show ?thesis by (unfold eq_e, auto)
-    next
-      case (thread_V thread cs)
-      assume eq_e: "e = V thread cs"
-      with ih show ?thesis by (unfold eq_e, auto)
-    next 
-      case (thread_set thread prio)
-      from vt_cons thread_set show ?thesis by simp
-    qed
-  next
-    case vt_nil
-    show ?case by (auto)
-  qed
-qed
-
-lemma Max_f_mono:
-  assumes seq: "A \<subseteq> B"
-  and np: "A \<noteq> {}"
-  and fnt: "finite B"
-  shows "Max (f ` A) \<le> Max (f ` B)"
-proof(rule Max_mono)
-  from seq show "f ` A \<subseteq> f ` B" by auto
-next
-  from np show "f ` A \<noteq> {}" by auto
-next
-  from fnt and seq show "finite (f ` B)" by auto
-qed
-
-lemma cp_le:
-  assumes vt: "vt step s"
-  and th_in: "th \<in> threads s"
-  shows "cp s th \<le> Max ((\<lambda> th. (preced th s)) ` threads s)"
-proof(unfold cp_eq_cpreced cpreced_def cs_dependents_def)
-  show "Max ((\<lambda>th. preced th s) ` ({th} \<union> {th'. (Th th', Th th) \<in> (depend (wq s))\<^sup>+}))
-         \<le> Max ((\<lambda>th. preced th s) ` threads s)"
-    (is "Max (?f ` ?A) \<le> Max (?f ` ?B)")
-  proof(rule Max_f_mono)
-    show "{th} \<union> {th'. (Th th', Th th) \<in> (depend (wq s))\<^sup>+} \<noteq> {}" by simp
-  next
-    from finite_threads [OF vt]
-    show "finite (threads s)" .
-  next
-    from th_in
-    show "{th} \<union> {th'. (Th th', Th th) \<in> (depend (wq s))\<^sup>+} \<subseteq> threads s"
-      apply (auto simp:Domain_def)
-      apply (rule_tac dm_depend_threads[OF vt])
-      apply (unfold trancl_domain [of "depend s", symmetric])
-      by (unfold cs_depend_def s_depend_def, auto simp:Domain_def)
-  qed
-qed
-
-lemma le_cp:
-  assumes vt: "vt step s"
-  shows "preced th s \<le> cp s th"
-proof(unfold cp_eq_cpreced preced_def cpreced_def, simp)
-  show "Prc (original_priority th s) (birthtime th s)
-    \<le> Max (insert (Prc (original_priority th s) (birthtime th s))
-            ((\<lambda>th. Prc (original_priority th s) (birthtime th s)) ` dependents (wq s) th))"
-    (is "?l \<le> Max (insert ?l ?A)")
-  proof(cases "?A = {}")
-    case False
-    have "finite ?A" (is "finite (?f ` ?B)")
-    proof -
-      have "finite ?B" 
-      proof-
-        have "finite {th'. (Th th', Th th) \<in> (depend (wq s))\<^sup>+}"
-        proof -
-          let ?F = "\<lambda> (x, y). the_th x"
-          have "{th'. (Th th', Th th) \<in> (depend (wq s))\<^sup>+} \<subseteq> ?F ` ((depend (wq s))\<^sup>+)"
-            apply (auto simp:image_def)
-            by (rule_tac x = "(Th x, Th th)" in bexI, auto)
-          moreover have "finite \<dots>"
-          proof -
-            from finite_depend[OF vt] have "finite (depend s)" .
-            hence "finite ((depend (wq s))\<^sup>+)"
-              apply (unfold finite_trancl)
-              by (auto simp: s_depend_def cs_depend_def wq_def)
-            thus ?thesis by auto
-          qed
-          ultimately show ?thesis by (auto intro:finite_subset)
-        qed
-        thus ?thesis by (simp add:cs_dependents_def)
-      qed
-      thus ?thesis by simp
-    qed
-    from Max_insert [OF this False, of ?l] show ?thesis by auto
-  next
-    case True
-    thus ?thesis by auto
-  qed
-qed
-
-lemma max_cp_eq: 
-  assumes vt: "vt step s"
-  shows "Max ((cp s) ` threads s) = Max ((\<lambda> th. (preced th s)) ` threads s)"
-  (is "?l = ?r")
-proof(cases "threads s = {}")
-  case True
-  thus ?thesis by auto
-next
-  case False
-  have "?l \<in> ((cp s) ` threads s)"
-  proof(rule Max_in)
-    from finite_threads[OF vt] 
-    show "finite (cp s ` threads s)" by auto
-  next
-    from False show "cp s ` threads s \<noteq> {}" by auto
-  qed
-  then obtain th 
-    where th_in: "th \<in> threads s" and eq_l: "?l = cp s th" by auto
-  have "\<dots> \<le> ?r" by (rule cp_le[OF vt th_in])
-  moreover have "?r \<le> cp s th" (is "Max (?f ` ?A) \<le> cp s th")
-  proof -
-    have "?r \<in> (?f ` ?A)"
-    proof(rule Max_in)
-      from finite_threads[OF vt]
-      show " finite ((\<lambda>th. preced th s) ` threads s)" by auto
-    next
-      from False show " (\<lambda>th. preced th s) ` threads s \<noteq> {}" by auto
-    qed
-    then obtain th' where 
-      th_in': "th' \<in> ?A " and eq_r: "?r = ?f th'" by auto
-    from le_cp [OF vt, of th']  eq_r
-    have "?r \<le> cp s th'" by auto
-    moreover have "\<dots> \<le> cp s th"
-    proof(fold eq_l)
-      show " cp s th' \<le> Max (cp s ` threads s)"
-      proof(rule Max_ge)
-        from th_in' show "cp s th' \<in> cp s ` threads s"
-          by auto
-      next
-        from finite_threads[OF vt]
-        show "finite (cp s ` threads s)" by auto
-      qed
-    qed
-    ultimately show ?thesis by auto
-  qed
-  ultimately show ?thesis using eq_l by auto
-qed
-
-lemma max_cp_readys_threads_pre:
-  assumes vt: "vt step s"
-  and np: "threads s \<noteq> {}"
-  shows "Max (cp s ` readys s) = Max (cp s ` threads s)"
-proof(unfold max_cp_eq[OF vt])
-  show "Max (cp s ` readys s) = Max ((\<lambda>th. preced th s) ` threads s)"
-  proof -
-    let ?p = "Max ((\<lambda>th. preced th s) ` threads s)" 
-    let ?f = "(\<lambda>th. preced th s)"
-    have "?p \<in> ((\<lambda>th. preced th s) ` threads s)"
-    proof(rule Max_in)
-      from finite_threads[OF vt] show "finite (?f ` threads s)" by simp
-    next
-      from np show "?f ` threads s \<noteq> {}" by simp
-    qed
-    then obtain tm where tm_max: "?f tm = ?p" and tm_in: "tm \<in> threads s"
-      by (auto simp:Image_def)
-    from th_chain_to_ready [OF vt tm_in]
-    have "tm \<in> readys s \<or> (\<exists>th'. th' \<in> readys s \<and> (Th tm, Th th') \<in> (depend s)\<^sup>+)" .
-    thus ?thesis
-    proof
-      assume "\<exists>th'. th' \<in> readys s \<and> (Th tm, Th th') \<in> (depend s)\<^sup>+ "
-      then obtain th' where th'_in: "th' \<in> readys s" 
-        and tm_chain:"(Th tm, Th th') \<in> (depend s)\<^sup>+" by auto
-      have "cp s th' = ?f tm"
-      proof(subst cp_eq_cpreced, subst cpreced_def, rule Max_eqI)
-        from dependents_threads[OF vt] finite_threads[OF vt]
-        show "finite ((\<lambda>th. preced th s) ` ({th'} \<union> dependents (wq s) th'))" 
-          by (auto intro:finite_subset)
-      next
-        fix p assume p_in: "p \<in> (\<lambda>th. preced th s) ` ({th'} \<union> dependents (wq s) th')"
-        from tm_max have " preced tm s = Max ((\<lambda>th. preced th s) ` threads s)" .
-        moreover have "p \<le> \<dots>"
-        proof(rule Max_ge)
-          from finite_threads[OF vt]
-          show "finite ((\<lambda>th. preced th s) ` threads s)" by simp
-        next
-          from p_in and th'_in and dependents_threads[OF vt, of th']
-          show "p \<in> (\<lambda>th. preced th s) ` threads s"
-            by (auto simp:readys_def)
-        qed
-        ultimately show "p \<le> preced tm s" by auto
-      next
-        show "preced tm s \<in> (\<lambda>th. preced th s) ` ({th'} \<union> dependents (wq s) th')"
-        proof -
-          from tm_chain
-          have "tm \<in> dependents (wq s) th'"
-            by (unfold cs_dependents_def s_depend_def cs_depend_def, auto)
-          thus ?thesis by auto
-        qed
-      qed
-      with tm_max
-      have h: "cp s th' = Max ((\<lambda>th. preced th s) ` threads s)" by simp
-      show ?thesis
-      proof (fold h, rule Max_eqI)
-        fix q 
-        assume "q \<in> cp s ` readys s"
-        then obtain th1 where th1_in: "th1 \<in> readys s"
-          and eq_q: "q = cp s th1" by auto
-        show "q \<le> cp s th'"
-          apply (unfold h eq_q)
-          apply (unfold cp_eq_cpreced cpreced_def)
-          apply (rule Max_mono)
-        proof -
-          from dependents_threads [OF vt, of th1] th1_in
-          show "(\<lambda>th. preced th s) ` ({th1} \<union> dependents (wq s) th1) \<subseteq> 
-                 (\<lambda>th. preced th s) ` threads s"
-            by (auto simp:readys_def)
-        next
-          show "(\<lambda>th. preced th s) ` ({th1} \<union> dependents (wq s) th1) \<noteq> {}" by simp
-        next
-          from finite_threads[OF vt] 
-          show " finite ((\<lambda>th. preced th s) ` threads s)" by simp
-        qed
-      next
-        from finite_threads[OF vt]
-        show "finite (cp s ` readys s)" by (auto simp:readys_def)
-      next
-        from th'_in
-        show "cp s th' \<in> cp s ` readys s" by simp
-      qed
-    next
-      assume tm_ready: "tm \<in> readys s"
-      show ?thesis
-      proof(fold tm_max)
-        have cp_eq_p: "cp s tm = preced tm s"
-        proof(unfold cp_eq_cpreced cpreced_def, rule Max_eqI)
-          fix y 
-          assume hy: "y \<in> (\<lambda>th. preced th s) ` ({tm} \<union> dependents (wq s) tm)"
-          show "y \<le> preced tm s"
-          proof -
-            { fix y'
-              assume hy' : "y' \<in> ((\<lambda>th. preced th s) ` dependents (wq s) tm)"
-              have "y' \<le> preced tm s"
-              proof(unfold tm_max, rule Max_ge)
-                from hy' dependents_threads[OF vt, of tm]
-                show "y' \<in> (\<lambda>th. preced th s) ` threads s" by auto
-              next
-                from finite_threads[OF vt] 
-                show "finite ((\<lambda>th. preced th s) ` threads s)" by simp
-              qed
-            } with hy show ?thesis by auto
-          qed
-        next
-          from dependents_threads[OF vt, of tm] finite_threads[OF vt]
-          show "finite ((\<lambda>th. preced th s) ` ({tm} \<union> dependents (wq s) tm))"
-            by (auto intro:finite_subset)
-        next
-          show "preced tm s \<in> (\<lambda>th. preced th s) ` ({tm} \<union> dependents (wq s) tm)"
-            by simp
-        qed 
-        moreover have "Max (cp s ` readys s) = cp s tm"
-        proof(rule Max_eqI)
-          from tm_ready show "cp s tm \<in> cp s ` readys s" by simp
-        next
-          from finite_threads[OF vt]
-          show "finite (cp s ` readys s)" by (auto simp:readys_def)
-        next
-          fix y assume "y \<in> cp s ` readys s"
-          then obtain th1 where th1_readys: "th1 \<in> readys s"
-            and h: "y = cp s th1" by auto
-          show "y \<le> cp s tm"
-            apply(unfold cp_eq_p h)
-            apply(unfold cp_eq_cpreced cpreced_def tm_max, rule Max_mono)
-          proof -
-            from finite_threads[OF vt]
-            show "finite ((\<lambda>th. preced th s) ` threads s)" by simp
-          next
-            show "(\<lambda>th. preced th s) ` ({th1} \<union> dependents (wq s) th1) \<noteq> {}"
-              by simp
-          next
-            from dependents_threads[OF vt, of th1] th1_readys
-            show "(\<lambda>th. preced th s) ` ({th1} \<union> dependents (wq s) th1) 
-                    \<subseteq> (\<lambda>th. preced th s) ` threads s"
-              by (auto simp:readys_def)
-          qed
-        qed
-        ultimately show " Max (cp s ` readys s) = preced tm s" by simp
-      qed 
-    qed
-  qed
-qed
-
-lemma max_cp_readys_threads:
-  assumes vt: "vt step s"
-  shows "Max (cp s ` readys s) = Max (cp s ` threads s)"
-proof(cases "threads s = {}")
-  case True
-  thus ?thesis 
-    by (auto simp:readys_def)
-next
-  case False
-  show ?thesis by (rule max_cp_readys_threads_pre[OF vt False])
-qed
-
-lemma readys_threads:
-  shows "readys s \<subseteq> threads s"
-proof
-  fix th
-  assume "th \<in> readys s"
-  thus "th \<in> threads s"
-    by (unfold readys_def, auto)
-qed
-
-lemma eq_holding: "holding (wq s) th cs = holding s th cs"
-  apply (unfold s_holding_def cs_holding_def, simp)
-  done
-
-lemma f_image_eq:
-  assumes h: "\<And> a. a \<in> A \<Longrightarrow> f a = g a"
-  shows "f ` A = g ` A"
-proof
-  show "f ` A \<subseteq> g ` A"
-    by(rule image_subsetI, auto intro:h)
-next
-  show "g ` A \<subseteq> f ` A"
-   by(rule image_subsetI, auto intro:h[symmetric])
-qed
-
-end
\ No newline at end of file