
diff -r e5bfdd2d1ac8 -r a3b4eed091d2 prio/Attic/Prio.thy
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/prio/Attic/Prio.thy	Sun Feb 05 21:00:12 2012 +0000
@@ -0,0 +1,2813 @@
+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




