
diff -r 17305a85493d -r c495eb16beb6 CpsG.thy
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/CpsG.thy	Wed Jan 27 19:28:42 2016 +0800
@@ -0,0 +1,4565 @@
+theory CpsG
+imports PIPDefs
+begin
+
+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
+
+lemma Max_fg_mono:
+  assumes "finite A"
+  and "\<forall> a \<in> A. f a \<le> g a"
+  shows "Max (f ` A) \<le> Max (g ` A)"
+proof(cases "A = {}")
+  case True
+  thus ?thesis by auto
+next
+  case False
+  show ?thesis
+  proof(rule Max.boundedI)
+    from assms show "finite (f ` A)" by auto
+  next
+    from False show "f ` A \<noteq> {}" by auto
+  next
+    fix fa
+    assume "fa \<in> f ` A"
+    then obtain a where h_fa: "a \<in> A" "fa = f a" by auto
+    show "fa \<le> Max (g ` A)"
+    proof(rule Max_ge_iff[THEN iffD2])
+      from assms show "finite (g ` A)" by auto
+    next
+      from False show "g ` A \<noteq> {}" by auto
+    next
+      from h_fa have "g a \<in> g ` A" by auto
+      moreover have "fa \<le> g a" using h_fa assms(2) by auto
+      ultimately show "\<exists>a\<in>g ` A. fa \<le> a" by auto
+    qed
+  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 Max_UNION: 
+  assumes "finite A"
+  and "A \<noteq> {}"
+  and "\<forall> M \<in> f ` A. finite M"
+  and "\<forall> M \<in> f ` A. M \<noteq> {}"
+  shows "Max (\<Union>x\<in> A. f x) = Max (Max ` f ` A)" (is "?L = ?R")
+  using assms[simp]
+proof -
+  have "?L = Max (\<Union>(f ` A))"
+    by (fold Union_image_eq, simp)
+  also have "... = ?R"
+    by (subst Max_Union, simp+)
+  finally show ?thesis .
+qed
+
+lemma max_Max_eq:
+  assumes "finite A"
+    and "A \<noteq> {}"
+    and "x = y"
+  shows "max x (Max A) = Max ({y} \<union> A)" (is "?L = ?R")
+proof -
+  have "?R = Max (insert y A)" by simp
+  also from assms have "... = ?L"
+      by (subst Max.insert, simp+)
+  finally show ?thesis by simp
+qed
+
+lemma eq_RAG: 
+  "RAG (wq s) = RAG s"
+  by (unfold cs_RAG_def s_RAG_def, auto)
+
+lemma waiting_holding:
+  assumes "waiting (s::state) th cs"
+  obtains th' where "holding s th' cs"
+proof -
+  from assms[unfolded s_waiting_def, folded wq_def]
+  obtain th' where "th' \<in> set (wq s cs)" "th' = hd (wq s cs)"
+    by (metis empty_iff hd_in_set list.set(1))
+  hence "holding s th' cs" 
+    by (unfold s_holding_def, fold wq_def, auto)
+  from that[OF this] show ?thesis .
+qed
+
+lemma cp_eq_cpreced: "cp s th = cpreced (wq s) s th"
+unfolding cp_def wq_def
+apply(induct s rule: schs.induct)
+apply(simp add: Let_def cpreced_initial)
+apply(simp add: Let_def)
+apply(simp add: Let_def)
+apply(simp add: Let_def)
+apply(subst (2) schs.simps)
+apply(simp add: Let_def)
+apply(subst (2) schs.simps)
+apply(simp add: Let_def)
+done
+
+lemma cp_alt_def:
+  "cp s th =  
+           Max ((the_preced s) ` {th'. Th th' \<in> (subtree (RAG s) (Th th))})"
+proof -
+  have "Max (the_preced s ` ({th} \<union> dependants (wq s) th)) =
+        Max (the_preced s ` {th'. Th th' \<in> subtree (RAG s) (Th th)})" 
+          (is "Max (_ ` ?L) = Max (_ ` ?R)")
+  proof -
+    have "?L = ?R" 
+    by (auto dest:rtranclD simp:cs_dependants_def cs_RAG_def s_RAG_def subtree_def)
+    thus ?thesis by simp
+  qed
+  thus ?thesis by (unfold cp_eq_cpreced cpreced_def, fold the_preced_def, simp)
+qed
+
+(* ccc *)
+
+
+locale valid_trace = 
+  fixes s
+  assumes vt : "vt s"
+
+locale valid_trace_e = valid_trace +
+  fixes e
+  assumes vt_e: "vt (e#s)"
+begin
+
+lemma pip_e: "PIP s e"
+  using vt_e by (cases, simp)  
+
+end
+
+locale valid_trace_create = valid_trace_e + 
+  fixes th prio
+  assumes is_create: "e = Create th prio"
+
+locale valid_trace_exit = valid_trace_e + 
+  fixes th
+  assumes is_exit: "e = Exit th"
+
+locale valid_trace_p = valid_trace_e + 
+  fixes th cs
+  assumes is_p: "e = P th cs"
+
+locale valid_trace_v = valid_trace_e + 
+  fixes th cs
+  assumes is_v: "e = V th cs"
+begin
+  definition "rest = tl (wq s cs)"
+  definition "wq' = (SOME q. distinct q \<and> set q = set rest)"
+end
+
+locale valid_trace_v_n = valid_trace_v +
+  assumes rest_nnl: "rest \<noteq> []"
+
+locale valid_trace_v_e = valid_trace_v +
+  assumes rest_nil: "rest = []"
+
+locale valid_trace_set= valid_trace_e + 
+  fixes th prio
+  assumes is_set: "e = Set th prio"
+
+context valid_trace
+begin
+
+lemma ind [consumes 0, case_names Nil Cons, induct type]:
+  assumes "PP []"
+     and "(\<And>s e. valid_trace_e s e \<Longrightarrow>
+                   PP s \<Longrightarrow> PIP s e \<Longrightarrow> PP (e # s))"
+     shows "PP s"
+proof(induct rule:vt.induct[OF vt, case_names Init Step])
+  case Init
+  from assms(1) show ?case .
+next
+  case (Step s e)
+  show ?case
+  proof(rule assms(2))
+    show "valid_trace_e s e" using Step by (unfold_locales, auto)
+  next
+    show "PP s" using Step by simp
+  next
+    show "PIP s e" using Step by simp
+  qed
+qed
+
+lemma  vt_moment: "\<And> t. vt (moment t s)"
+proof(induct rule:ind)
+  case Nil
+  thus ?case by (simp add:vt_nil)
+next
+  case (Cons s e t)
+  show ?case
+  proof(cases "t \<ge> length (e#s)")
+    case True
+    from True have "moment t (e#s) = e#s" by simp
+    thus ?thesis using Cons
+      by (simp add:valid_trace_def valid_trace_e_def, auto)
+  next
+    case False
+    from Cons have "vt (moment t s)" by simp
+    moreover have "moment t (e#s) = moment t s"
+    proof -
+      from False have "t \<le> length s" by simp
+      from moment_app [OF this, of "[e]"] 
+      show ?thesis by simp
+    qed
+    ultimately show ?thesis by simp
+  qed
+qed
+
+lemma finite_threads:
+  shows "finite (threads s)"
+using vt by (induct) (auto elim: step.cases)
+
+end
+
+lemma RAG_target_th: "(Th th, x) \<in> RAG (s::state) \<Longrightarrow> \<exists> cs. x = Cs cs"
+  by (unfold s_RAG_def, auto)
+
+locale valid_moment = valid_trace + 
+  fixes i :: nat
+
+sublocale valid_moment < vat_moment: valid_trace "(moment i s)"
+  by (unfold_locales, insert vt_moment, auto)
+
+lemma waiting_eq: "waiting s th cs = waiting (wq s) th cs"
+  by  (unfold s_waiting_def cs_waiting_def wq_def, auto)
+
+lemma holding_eq: "holding (s::state) th cs = holding (wq s) th cs"
+  by (unfold s_holding_def wq_def cs_holding_def, simp)
+
+lemma runing_ready: 
+  shows "runing s \<subseteq> readys s"
+  unfolding runing_def readys_def
+  by auto 
+
+lemma readys_threads:
+  shows "readys s \<subseteq> threads s"
+  unfolding readys_def
+  by auto
+
+lemma wq_v_neq [simp]:
+   "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 runing_head:
+  assumes "th \<in> runing s"
+  and "th \<in> set (wq_fun (schs s) cs)"
+  shows "th = hd (wq_fun (schs s) cs)"
+  using assms
+  by (simp add:runing_def readys_def s_waiting_def wq_def)
+
+context valid_trace
+begin
+
+lemma runing_wqE:
+  assumes "th \<in> runing s"
+  and "th \<in> set (wq s cs)"
+  obtains rest where "wq s cs = th#rest"
+proof -
+  from assms(2) obtain th' rest where eq_wq: "wq s cs = th'#rest"
+    by (meson list.set_cases)
+  have "th' = th"
+  proof(rule ccontr)
+    assume "th' \<noteq> th"
+    hence "th \<noteq> hd (wq s cs)" using eq_wq by auto 
+    with assms(2)
+    have "waiting s th cs" 
+      by (unfold s_waiting_def, fold wq_def, auto)
+    with assms show False 
+      by (unfold runing_def readys_def, auto)
+  qed
+  with eq_wq that show ?thesis by metis
+qed
+
+end
+
+context valid_trace_create
+begin
+
+lemma wq_neq_simp [simp]:
+  shows "wq (e#s) cs' = wq s cs'"
+    using assms unfolding is_create wq_def
+  by (auto simp:Let_def)
+
+lemma wq_distinct_kept:
+  assumes "distinct (wq s cs')"
+  shows "distinct (wq (e#s) cs')"
+  using assms by simp
+end
+
+context valid_trace_exit
+begin
+
+lemma wq_neq_simp [simp]:
+  shows "wq (e#s) cs' = wq s cs'"
+    using assms unfolding is_exit wq_def
+  by (auto simp:Let_def)
+
+lemma wq_distinct_kept:
+  assumes "distinct (wq s cs')"
+  shows "distinct (wq (e#s) cs')"
+  using assms by simp
+end
+
+context valid_trace_p
+begin
+
+lemma wq_neq_simp [simp]:
+  assumes "cs' \<noteq> cs"
+  shows "wq (e#s) cs' = wq s cs'"
+    using assms unfolding is_p wq_def
+  by (auto simp:Let_def)
+
+lemma runing_th_s:
+  shows "th \<in> runing s"
+proof -
+  from pip_e[unfolded is_p]
+  show ?thesis by (cases, simp)
+qed
+
+lemma ready_th_s: "th \<in> readys s"
+  using runing_th_s
+  by (unfold runing_def, auto)
+
+lemma live_th_s: "th \<in> threads s"
+  using readys_threads ready_th_s by auto
+
+lemma live_th_es: "th \<in> threads (e#s)"
+  using live_th_s 
+  by (unfold is_p, simp)
+
+lemma th_not_waiting: 
+  "\<not> waiting s th c"
+proof -
+  have "th \<in> readys s"
+    using runing_ready runing_th_s by blast 
+  thus ?thesis
+    by (unfold readys_def, auto)
+qed
+
+lemma waiting_neq_th: 
+  assumes "waiting s t c"
+  shows "t \<noteq> th"
+  using assms using th_not_waiting by blast 
+
+lemma th_not_in_wq: 
+  shows "th \<notin> set (wq s cs)"
+proof
+  assume otherwise: "th \<in> set (wq s cs)"
+  from runing_wqE[OF runing_th_s this]
+  obtain rest where eq_wq: "wq s cs = th#rest" by blast
+  with otherwise
+  have "holding s th cs"
+    by (unfold s_holding_def, fold wq_def, simp)
+  hence cs_th_RAG: "(Cs cs, Th th) \<in> RAG s"
+    by (unfold s_RAG_def, fold holding_eq, auto)
+  from pip_e[unfolded is_p]
+  show False
+  proof(cases)
+    case (thread_P)
+    with cs_th_RAG show ?thesis by auto
+  qed
+qed
+
+lemma wq_es_cs: 
+  "wq (e#s) cs =  wq s cs @ [th]"
+  by (unfold is_p wq_def, auto simp:Let_def)
+
+lemma wq_distinct_kept:
+  assumes "distinct (wq s cs')"
+  shows "distinct (wq (e#s) cs')"
+proof(cases "cs' = cs")
+  case True
+  show ?thesis using True assms th_not_in_wq
+    by (unfold True wq_es_cs, auto)
+qed (insert assms, simp)
+
+end
+
+context valid_trace_v
+begin
+
+lemma wq_neq_simp [simp]:
+  assumes "cs' \<noteq> cs"
+  shows "wq (e#s) cs' = wq s cs'"
+    using assms unfolding is_v wq_def
+  by (auto simp:Let_def)
+
+lemma runing_th_s:
+  shows "th \<in> runing s"
+proof -
+  from pip_e[unfolded is_v]
+  show ?thesis by (cases, simp)
+qed
+
+lemma th_not_waiting: 
+  "\<not> waiting s th c"
+proof -
+  have "th \<in> readys s"
+    using runing_ready runing_th_s by blast 
+  thus ?thesis
+    by (unfold readys_def, auto)
+qed
+
+lemma waiting_neq_th: 
+  assumes "waiting s t c"
+  shows "t \<noteq> th"
+  using assms using th_not_waiting by blast 
+
+lemma wq_s_cs:
+  "wq s cs = th#rest"
+proof -
+  from pip_e[unfolded is_v]
+  show ?thesis
+  proof(cases)
+    case (thread_V)
+    from this(2) show ?thesis
+      by (unfold rest_def s_holding_def, fold wq_def,
+                 metis empty_iff list.collapse list.set(1))
+  qed
+qed
+
+lemma wq_es_cs:
+  "wq (e#s) cs = wq'"
+ using wq_s_cs[unfolded wq_def]
+ by (auto simp:Let_def wq_def rest_def wq'_def is_v, simp) 
+
+lemma wq_distinct_kept:
+  assumes "distinct (wq s cs')"
+  shows "distinct (wq (e#s) cs')"
+proof(cases "cs' = cs")
+  case True
+  show ?thesis
+  proof(unfold True wq_es_cs wq'_def, rule someI2)
+    show "distinct rest \<and> set rest = set rest"
+        using assms[unfolded True wq_s_cs] by auto
+  qed simp
+qed (insert assms, simp)
+
+end
+
+context valid_trace_set
+begin
+
+lemma wq_neq_simp [simp]:
+  shows "wq (e#s) cs' = wq s cs'"
+    using assms unfolding is_set wq_def
+  by (auto simp:Let_def)
+
+lemma wq_distinct_kept:
+  assumes "distinct (wq s cs')"
+  shows "distinct (wq (e#s) cs')"
+  using assms by simp
+end
+
+context valid_trace
+begin
+
+lemma actor_inv: 
+  assumes "PIP s e"
+  and "\<not> isCreate e"
+  shows "actor e \<in> runing s"
+  using assms
+  by (induct, auto)
+
+lemma isP_E:
+  assumes "isP e"
+  obtains cs where "e = P (actor e) cs"
+  using assms by (cases e, auto)
+
+lemma isV_E:
+  assumes "isV e"
+  obtains cs where "e = V (actor e) cs"
+  using assms by (cases e, auto) 
+
+lemma wq_distinct: "distinct (wq s cs)"
+proof(induct rule:ind)
+  case (Cons s e)
+  interpret vt_e: valid_trace_e s e using Cons by simp
+  show ?case 
+  proof(cases e)
+    case (Create th prio)
+    interpret vt_create: valid_trace_create s e th prio 
+      using Create by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt_create.wq_distinct_kept) 
+  next
+    case (Exit th)
+    interpret vt_exit: valid_trace_exit s e th  
+        using Exit by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt_exit.wq_distinct_kept) 
+  next
+    case (P th cs)
+    interpret vt_p: valid_trace_p s e th cs using P by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt_p.wq_distinct_kept) 
+  next
+    case (V th cs)
+    interpret vt_v: valid_trace_v s e th cs using V by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt_v.wq_distinct_kept) 
+  next
+    case (Set th prio)
+    interpret vt_set: valid_trace_set s e th prio
+        using Set by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt_set.wq_distinct_kept) 
+  qed
+qed (unfold wq_def Let_def, simp)
+
+end
+
+context valid_trace_e
+begin
+
+text {*
+  The following lemma shows that only the @{text "P"}
+  operation can add new thread into waiting queues. 
+  Such kind of lemmas are very obvious, but need to be checked formally.
+  This is a kind of confirmation that our modelling is correct.
+*}
+
+lemma wq_in_inv: 
+  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(cases e)
+  -- {* This is the only non-trivial case: *}
+  case (V th cs1)
+  have False
+  proof(cases "cs1 = cs")
+    case True
+    show ?thesis
+    proof(cases "(wq s cs1)")
+      case (Cons w_hd w_tl)
+      have "set (wq (e#s) cs) \<subseteq> set (wq s cs)"
+      proof -
+        have "(wq (e#s) cs) = (SOME q. distinct q \<and> set q = set w_tl)"
+          using  Cons V by (auto simp:wq_def Let_def True split:if_splits)
+        moreover have "set ... \<subseteq> set (wq s cs)"
+        proof(rule someI2)
+          show "distinct w_tl \<and> set w_tl = set w_tl"
+            by (metis distinct.simps(2) local.Cons wq_distinct)
+        qed (insert Cons True, auto)
+        ultimately show ?thesis by simp
+      qed
+      with assms show ?thesis by auto
+    qed (insert assms V True, auto simp:wq_def Let_def split:if_splits)
+  qed (insert assms V, auto simp:wq_def Let_def split:if_splits)
+  thus ?thesis by auto
+qed (insert assms, auto simp:wq_def Let_def split:if_splits)
+
+lemma wq_out_inv: 
+  assumes s_in: "thread \<in> set (wq s cs)"
+  and s_hd: "thread = hd (wq s cs)"
+  and s_i: "thread \<noteq> hd (wq (e#s) cs)"
+  shows "e = V thread cs"
+proof(cases e)
+-- {* There are only two non-trivial cases: *}
+  case (V th cs1)
+  show ?thesis
+  proof(cases "cs1 = cs")
+    case True
+    have "PIP s (V th cs)" using pip_e[unfolded V[unfolded True]] .
+    thus ?thesis
+    proof(cases)
+      case (thread_V)
+      moreover have "th = thread" using thread_V(2) s_hd
+          by (unfold s_holding_def wq_def, simp)
+      ultimately show ?thesis using V True by simp
+    qed
+  qed (insert assms V, auto simp:wq_def Let_def split:if_splits)
+next
+  case (P th cs1)
+  show ?thesis
+  proof(cases "cs1 = cs")
+    case True
+    with P have "wq (e#s) cs = wq_fun (schs s) cs @ [th]"
+      by (auto simp:wq_def Let_def split:if_splits)
+    with s_i s_hd s_in have False
+      by (metis empty_iff hd_append2 list.set(1) wq_def) 
+    thus ?thesis by simp
+  qed (insert assms P, auto simp:wq_def Let_def split:if_splits)
+qed (insert assms, auto simp:wq_def Let_def split:if_splits)
+
+end
+
+
+context valid_trace
+begin
+
+
+text {* (* ddd *)
+  The nature of the work is like this: since it starts from a very simple and basic 
+  model, even intuitively very `basic` and `obvious` properties need to derived from scratch.
+  For instance, the fact 
+  that one thread can not be blocked by two critical resources at the same time
+  is obvious, because only running threads can make new requests, if one is waiting for 
+  a critical resource and get blocked, it can not make another resource request and get 
+  blocked the second time (because it is not running). 
+
+  To derive this fact, one needs to prove by contraction and 
+  reason about time (or @{text "moement"}). The reasoning is based on a generic theorem
+  named @{text "p_split"}, which is about status changing along the time axis. It says if 
+  a condition @{text "Q"} is @{text "True"} at a state @{text "s"},
+  but it was @{text "False"} at the very beginning, then there must exits a moment @{text "t"} 
+  in the history of @{text "s"} (notice that @{text "s"} itself is essentially the history 
+  of events leading to it), such that @{text "Q"} switched 
+  from being @{text "False"} to @{text "True"} and kept being @{text "True"}
+  till the last moment of @{text "s"}.
+
+  Suppose a thread @{text "th"} is blocked
+  on @{text "cs1"} and @{text "cs2"} in some state @{text "s"}, 
+  since no thread is blocked at the very beginning, by applying 
+  @{text "p_split"} to these two blocking facts, there exist 
+  two moments @{text "t1"} and @{text "t2"}  in @{text "s"}, such that 
+  @{text "th"} got blocked on @{text "cs1"} and @{text "cs2"} 
+  and kept on blocked on them respectively ever since.
+ 
+  Without lost of generality, we assume @{text "t1"} is earlier than @{text "t2"}.
+  However, since @{text "th"} was blocked ever since memonent @{text "t1"}, so it was still
+  in blocked state at moment @{text "t2"} and could not
+  make any request and get blocked the second time: Contradiction.
+*}
+
+lemma waiting_unique_pre: (* ddd *)
+  assumes 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" = "\<lambda> 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> ?Q cs1 (moment t1 s)"
+    and nn1: "(\<forall>i'>t1. ?Q cs1 (moment i' s))" by auto
+  from p_split [of "?Q cs2", OF q2 nq2]
+  obtain t2 where lt2: "t2 < length s"
+    and np2: "\<not> ?Q cs2 (moment t2 s)"
+    and nn2: "(\<forall>i'>t2. ?Q cs2 (moment i' s))" by auto
+  { fix s cs
+    assume q: "?Q cs s"
+    have "thread \<notin> runing s"
+    proof
+      assume "thread \<in> runing s"
+      hence " \<forall>cs. \<not> (thread \<in> set (wq_fun (schs s) cs) \<and> 
+                 thread \<noteq> hd (wq_fun (schs s) cs))"
+        by (unfold runing_def s_waiting_def readys_def, auto)
+      from this[rule_format, of cs] q 
+      show False by (simp add: wq_def) 
+    qed
+  } note q_not_runing = this
+  { fix t1 t2 cs1 cs2
+    assume  lt1: "t1 < length s"
+    and np1: "\<not> ?Q cs1 (moment t1 s)"
+    and nn1: "(\<forall>i'>t1. ?Q cs1 (moment i' s))"
+    and lt2: "t2 < length s"
+    and np2: "\<not> ?Q cs2 (moment t2 s)"
+    and nn2: "(\<forall>i'>t2. ?Q cs2 (moment i' s))"
+    and 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#moment t2 s)"
+    proof -
+      from vt_moment 
+      have "vt (moment ?t3 s)" .
+      with eq_m show ?thesis by simp
+    qed
+    then interpret vt_e: valid_trace_e "moment t2 s" "e"
+        by (unfold_locales, auto, cases, simp)
+    have ?thesis
+    proof -
+      have "thread \<in> runing (moment t2 s)"
+      proof(cases "thread \<in> set (wq (moment t2 s) cs2)")
+        case True
+        have "e = V thread cs2"
+        proof -
+          have eq_th: "thread = hd (wq (moment t2 s) cs2)" 
+              using True and np2  by auto 
+          from vt_e.wq_out_inv[OF True this h2]
+          show ?thesis .
+        qed
+        thus ?thesis using vt_e.actor_inv[OF vt_e.pip_e] by auto
+      next
+        case False
+        have "e = P thread cs2" using vt_e.wq_in_inv[OF False h1] .
+        with vt_e.actor_inv[OF vt_e.pip_e]
+        show ?thesis by auto
+      qed
+      moreover have "thread \<notin> runing (moment t2 s)"
+        by (rule q_not_runing[OF nn1[rule_format, OF lt12]])
+      ultimately show ?thesis by simp
+    qed
+  } note lt_case = this
+  show ?thesis
+  proof -
+    { assume "t1 < t2"
+      from lt_case[OF lt1 np1 nn1 lt2 np2 nn2 this]
+      have ?thesis .
+    } moreover {
+      assume "t2 < t1"
+      from lt_case[OF lt2 np2 nn2 lt1 np1 nn1 this]
+      have ?thesis .
+    } moreover {
+      assume eq_12: "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 lt_2: "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
+      from nn1[rule_format, OF lt_2[folded eq_12]] eq_m[folded eq_12]
+      have g1: "thread \<in> set (wq (e#moment t1 s) cs1)" and
+           g2: "thread \<noteq> hd (wq (e#moment t1 s) cs1)" by auto
+      have "vt (e#moment t2 s)"
+      proof -
+        from vt_moment 
+        have "vt (moment ?t3 s)" .
+        with eq_m show ?thesis by simp
+      qed
+      then interpret vt_e: valid_trace_e "moment t2 s" "e"
+          by (unfold_locales, auto, cases, simp)
+      have "e = V thread cs2 \<or> e = P thread cs2"
+      proof(cases "thread \<in> set (wq (moment t2 s) cs2)")
+        case True
+        have "e = V thread cs2"
+        proof -
+          have eq_th: "thread = hd (wq (moment t2 s) cs2)" 
+              using True and np2  by auto 
+          from vt_e.wq_out_inv[OF True this h2]
+          show ?thesis .
+        qed
+        thus ?thesis by auto
+      next
+        case False
+        have "e = P thread cs2" using vt_e.wq_in_inv[OF False h1] .
+        thus ?thesis by auto
+      qed
+      moreover have "e = V thread cs1 \<or> e = P thread cs1"
+      proof(cases "thread \<in> set (wq (moment t1 s) cs1)")
+        case True
+        have eq_th: "thread = hd (wq (moment t1 s) cs1)" 
+              using True and np1  by auto 
+        from vt_e.wq_out_inv[folded eq_12, OF True this g2]
+        have "e = V thread cs1" .
+        thus ?thesis by auto
+      next
+        case False
+        have "e = P thread cs1" using vt_e.wq_in_inv[folded eq_12, OF False g1] .
+        thus ?thesis by auto
+      qed
+      ultimately have ?thesis using neq12 by auto
+    } ultimately show ?thesis using nat_neq_iff by blast 
+  qed
+qed
+
+text {*
+  This lemma is a simple corrolary of @{text "waiting_unique_pre"}.
+*}
+
+lemma waiting_unique:
+  assumes "waiting s th cs1"
+  and "waiting s th cs2"
+  shows "cs1 = cs2"
+  using waiting_unique_pre assms
+  unfolding wq_def s_waiting_def
+  by auto
+
+end
+
+(* not used *)
+text {*
+  Every thread can only be blocked on one critical resource, 
+  symmetrically, every critical resource can only be held by one thread. 
+  This fact is much more easier according to our definition. 
+*}
+lemma held_unique:
+  assumes "holding (s::event list) th1 cs"
+  and "holding s th2 cs"
+  shows "th1 = th2"
+ by (insert assms, unfold s_holding_def, auto)
+
+lemma last_set_lt: "th \<in> threads s \<Longrightarrow> last_set th s < length s"
+  apply (induct s, auto)
+  by (case_tac a, auto split:if_splits)
+
+lemma last_set_unique: 
+  "\<lbrakk>last_set th1 s = last_set 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:last_set_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 "last_set th1 s = last_set th2 s" by (simp add:preced_def)
+  from last_set_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
+
+text {*
+  The following three lemmas show that @{text "RAG"} does not change
+  by the happening of @{text "Set"}, @{text "Create"} and @{text "Exit"}
+  events, respectively.
+*}
+
+lemma RAG_set_unchanged: "(RAG (Set th prio # s)) = RAG s"
+apply (unfold s_RAG_def s_waiting_def wq_def)
+by (simp add:Let_def)
+
+lemma (in valid_trace_set)
+   RAG_unchanged: "(RAG (e # s)) = RAG s"
+   by (unfold is_set RAG_set_unchanged, simp)
+
+lemma RAG_create_unchanged: "(RAG (Create th prio # s)) = RAG s"
+apply (unfold s_RAG_def s_waiting_def wq_def)
+by (simp add:Let_def)
+
+lemma (in valid_trace_create)
+   RAG_unchanged: "(RAG (e # s)) = RAG s"
+   by (unfold is_create RAG_create_unchanged, simp)
+
+lemma RAG_exit_unchanged: "(RAG (Exit th # s)) = RAG s"
+apply (unfold s_RAG_def s_waiting_def wq_def)
+by (simp add:Let_def)
+
+lemma (in valid_trace_exit)
+   RAG_unchanged: "(RAG (e # s)) = RAG s"
+   by (unfold is_exit RAG_exit_unchanged, simp)
+
+context valid_trace_v
+begin
+
+lemma distinct_rest: "distinct rest"
+  by (simp add: distinct_tl rest_def wq_distinct)
+
+lemma holding_cs_eq_th:
+  assumes "holding s t cs"
+  shows "t = th"
+proof -
+  from pip_e[unfolded is_v]
+  show ?thesis
+  proof(cases)
+    case (thread_V)
+    from held_unique[OF this(2) assms]
+    show ?thesis by simp
+  qed
+qed
+
+lemma distinct_wq': "distinct wq'"
+  by (metis (mono_tags, lifting) distinct_rest  some_eq_ex wq'_def)
+  
+lemma set_wq': "set wq' = set rest"
+  by (metis (mono_tags, lifting) distinct_rest rest_def 
+      some_eq_ex wq'_def)
+    
+lemma th'_in_inv:
+  assumes "th' \<in> set wq'"
+  shows "th' \<in> set rest"
+  using assms set_wq' by simp
+
+lemma neq_t_th: 
+  assumes "waiting (e#s) t c"
+  shows "t \<noteq> th"
+proof
+  assume otherwise: "t = th"
+  show False
+  proof(cases "c = cs")
+    case True
+    have "t \<in> set wq'" 
+     using assms[unfolded True s_waiting_def, folded wq_def, unfolded wq_es_cs]
+     by simp 
+    from th'_in_inv[OF this] have "t \<in> set rest" .
+    with wq_s_cs[folded otherwise] wq_distinct[of cs]
+    show ?thesis by simp
+  next
+    case False
+    have "wq (e#s) c = wq s c" using False
+        by (unfold is_v, simp)
+    hence "waiting s t c" using assms 
+        by (simp add: cs_waiting_def waiting_eq)
+    hence "t \<notin> readys s" by (unfold readys_def, auto)
+    hence "t \<notin> runing s" using runing_ready by auto 
+    with runing_th_s[folded otherwise] show ?thesis by auto
+  qed
+qed
+
+lemma waiting_esI1:
+  assumes "waiting s t c"
+      and "c \<noteq> cs" 
+  shows "waiting (e#s) t c" 
+proof -
+  have "wq (e#s) c = wq s c" 
+    using assms(2) is_v by auto
+  with assms(1) show ?thesis 
+    using cs_waiting_def waiting_eq by auto 
+qed
+
+lemma holding_esI2:
+  assumes "c \<noteq> cs" 
+  and "holding s t c"
+  shows "holding (e#s) t c"
+proof -
+  from assms(1) have "wq (e#s) c = wq s c" using is_v by auto
+  from assms(2)[unfolded s_holding_def, folded wq_def, 
+                folded this, unfolded wq_def, folded s_holding_def]
+  show ?thesis .
+qed
+
+lemma holding_esI1:
+  assumes "holding s t c"
+  and "t \<noteq> th"
+  shows "holding (e#s) t c"
+proof -
+  have "c \<noteq> cs" using assms using holding_cs_eq_th by blast 
+  from holding_esI2[OF this assms(1)]
+  show ?thesis .
+qed
+
+end
+
+context valid_trace_v_n
+begin
+
+lemma neq_wq': "wq' \<noteq> []" 
+proof (unfold wq'_def, rule someI2)
+  show "distinct rest \<and> set rest = set rest"
+    by (simp add: distinct_rest) 
+next
+  fix x
+  assume " distinct x \<and> set x = set rest" 
+  thus "x \<noteq> []" using rest_nnl by auto
+qed 
+
+definition "taker = hd wq'"
+
+definition "rest' = tl wq'"
+
+lemma eq_wq': "wq' = taker # rest'"
+  by (simp add: neq_wq' rest'_def taker_def)
+
+lemma next_th_taker: 
+  shows "next_th s th cs taker"
+  using rest_nnl taker_def wq'_def wq_s_cs 
+  by (auto simp:next_th_def)
+
+lemma taker_unique: 
+  assumes "next_th s th cs taker'"
+  shows "taker' = taker"
+proof -
+  from assms
+  obtain rest' where 
+    h: "wq s cs = th # rest'" 
+       "taker' = hd (SOME q. distinct q \<and> set q = set rest')"
+          by (unfold next_th_def, auto)
+  with wq_s_cs have "rest' = rest" by auto
+  thus ?thesis using h(2) taker_def wq'_def by auto 
+qed
+
+lemma waiting_set_eq:
+  "{(Th th', Cs cs) |th'. next_th s th cs th'} = {(Th taker, Cs cs)}"
+  by (smt all_not_in_conv bot.extremum insertI1 insert_subset 
+      mem_Collect_eq next_th_taker subsetI subset_antisym taker_def taker_unique)
+
+lemma holding_set_eq:
+  "{(Cs cs, Th th') |th'.  next_th s th cs th'} = {(Cs cs, Th taker)}"
+  using next_th_taker taker_def waiting_set_eq 
+  by fastforce
+   
+lemma holding_taker:
+  shows "holding (e#s) taker cs"
+    by (unfold s_holding_def, fold wq_def, unfold wq_es_cs, 
+        auto simp:neq_wq' taker_def)
+
+lemma waiting_esI2:
+  assumes "waiting s t cs"
+      and "t \<noteq> taker"
+  shows "waiting (e#s) t cs" 
+proof -
+  have "t \<in> set wq'" 
+  proof(unfold wq'_def, rule someI2)
+    show "distinct rest \<and> set rest = set rest"
+          by (simp add: distinct_rest)
+  next
+    fix x
+    assume "distinct x \<and> set x = set rest"
+    moreover have "t \<in> set rest"
+        using assms(1) cs_waiting_def waiting_eq wq_s_cs by auto 
+    ultimately show "t \<in> set x" by simp
+  qed
+  moreover have "t \<noteq> hd wq'"
+    using assms(2) taker_def by auto 
+  ultimately show ?thesis
+    by (unfold s_waiting_def, fold wq_def, unfold wq_es_cs, simp)
+qed
+
+lemma waiting_esE:
+  assumes "waiting (e#s) t c" 
+  obtains "c \<noteq> cs" "waiting s t c"
+     |    "c = cs" "t \<noteq> taker" "waiting s t cs" "t \<in> set rest'"
+proof(cases "c = cs")
+  case False
+  hence "wq (e#s) c = wq s c" using is_v by auto
+  with assms have "waiting s t c" using cs_waiting_def waiting_eq by auto 
+  from that(1)[OF False this] show ?thesis .
+next
+  case True
+  from assms[unfolded s_waiting_def True, folded wq_def, unfolded wq_es_cs]
+  have "t \<noteq> hd wq'" "t \<in> set wq'" by auto
+  hence "t \<noteq> taker" by (simp add: taker_def) 
+  moreover hence "t \<noteq> th" using assms neq_t_th by blast 
+  moreover have "t \<in> set rest" by (simp add: `t \<in> set wq'` th'_in_inv) 
+  ultimately have "waiting s t cs"
+    by (metis cs_waiting_def list.distinct(2) list.sel(1) 
+                list.set_sel(2) rest_def waiting_eq wq_s_cs)  
+  show ?thesis using that(2)
+  using True `t \<in> set wq'` `t \<noteq> taker` `waiting s t cs` eq_wq' by auto   
+qed
+
+lemma holding_esI1:
+  assumes "c = cs"
+  and "t = taker"
+  shows "holding (e#s) t c"
+  by (unfold assms, simp add: holding_taker)
+
+lemma holding_esE:
+  assumes "holding (e#s) t c" 
+  obtains "c = cs" "t = taker"
+      | "c \<noteq> cs" "holding s t c"
+proof(cases "c = cs")
+  case True
+  from assms[unfolded True, unfolded s_holding_def, 
+             folded wq_def, unfolded wq_es_cs]
+  have "t = taker" by (simp add: taker_def) 
+  from that(1)[OF True this] show ?thesis .
+next
+  case False
+  hence "wq (e#s) c = wq s c" using is_v by auto
+  from assms[unfolded s_holding_def, folded wq_def, 
+             unfolded this, unfolded wq_def, folded s_holding_def]
+  have "holding s t c"  .
+  from that(2)[OF False this] show ?thesis .
+qed
+
+end 
+
+
+context valid_trace_v_e
+begin
+
+lemma nil_wq': "wq' = []" 
+proof (unfold wq'_def, rule someI2)
+  show "distinct rest \<and> set rest = set rest"
+    by (simp add: distinct_rest) 
+next
+  fix x
+  assume " distinct x \<and> set x = set rest" 
+  thus "x = []" using rest_nil by auto
+qed 
+
+lemma no_taker: 
+  assumes "next_th s th cs taker"
+  shows "False"
+proof -
+  from assms[unfolded next_th_def]
+  obtain rest' where "wq s cs = th # rest'" "rest' \<noteq> []"
+    by auto
+  thus ?thesis using rest_def rest_nil by auto 
+qed
+
+lemma waiting_set_eq:
+  "{(Th th', Cs cs) |th'. next_th s th cs th'} = {}"
+  using no_taker by auto
+
+lemma holding_set_eq:
+  "{(Cs cs, Th th') |th'.  next_th s th cs th'} = {}"
+  using no_taker by auto
+   
+lemma no_holding:
+  assumes "holding (e#s) taker cs"
+  shows False
+proof -
+  from wq_es_cs[unfolded nil_wq']
+  have " wq (e # s) cs = []" .
+  from assms[unfolded s_holding_def, folded wq_def, unfolded this]
+  show ?thesis by auto
+qed
+
+lemma no_waiting:
+  assumes "waiting (e#s) t cs"
+  shows False
+proof -
+  from wq_es_cs[unfolded nil_wq']
+  have " wq (e # s) cs = []" .
+  from assms[unfolded s_waiting_def, folded wq_def, unfolded this]
+  show ?thesis by auto
+qed
+
+lemma waiting_esI2:
+  assumes "waiting s t c"
+  shows "waiting (e#s) t c"
+proof -
+  have "c \<noteq> cs" using assms
+    using cs_waiting_def rest_nil waiting_eq wq_s_cs by auto 
+  from waiting_esI1[OF assms this]
+  show ?thesis .
+qed
+
+lemma waiting_esE:
+  assumes "waiting (e#s) t c" 
+  obtains "c \<noteq> cs" "waiting s t c"
+proof(cases "c = cs")
+  case False
+  hence "wq (e#s) c = wq s c" using is_v by auto
+  with assms have "waiting s t c" using cs_waiting_def waiting_eq by auto 
+  from that(1)[OF False this] show ?thesis .
+next
+  case True
+  from no_waiting[OF assms[unfolded True]]
+  show ?thesis by auto
+qed
+
+lemma holding_esE:
+  assumes "holding (e#s) t c" 
+  obtains "c \<noteq> cs" "holding s t c"
+proof(cases "c = cs")
+  case True
+  from no_holding[OF assms[unfolded True]] 
+  show ?thesis by auto
+next
+  case False
+  hence "wq (e#s) c = wq s c" using is_v by auto
+  from assms[unfolded s_holding_def, folded wq_def, 
+             unfolded this, unfolded wq_def, folded s_holding_def]
+  have "holding s t c"  .
+  from that[OF False this] show ?thesis .
+qed
+
+end 
+
+lemma rel_eqI:
+  assumes "\<And> x y. (x,y) \<in> A \<Longrightarrow> (x,y) \<in> B"
+  and "\<And> x y. (x,y) \<in> B \<Longrightarrow> (x, y) \<in> A"
+  shows "A = B"
+  using assms by auto
+
+lemma in_RAG_E:
+  assumes "(n1, n2) \<in> RAG (s::state)"
+  obtains (waiting) th cs where "n1 = Th th" "n2 = Cs cs" "waiting s th cs"
+      | (holding) th cs where "n1 = Cs cs" "n2 = Th th" "holding s th cs"
+  using assms[unfolded s_RAG_def, folded waiting_eq holding_eq]
+  by auto
+  
+context valid_trace_v
+begin
+
+lemma RAG_es:
+  "RAG (e # s) =
+   RAG s - {(Cs cs, Th th)} -
+     {(Th th', Cs cs) |th'. next_th s th cs th'} \<union>
+     {(Cs cs, Th th') |th'.  next_th s th cs th'}" (is "?L = ?R")
+proof(rule rel_eqI)
+  fix n1 n2
+  assume "(n1, n2) \<in> ?L"
+  thus "(n1, n2) \<in> ?R"
+  proof(cases rule:in_RAG_E)
+    case (waiting th' cs')
+    show ?thesis
+    proof(cases "rest = []")
+      case False
+      interpret h_n: valid_trace_v_n s e th cs
+        by (unfold_locales, insert False, simp)
+      from waiting(3)
+      show ?thesis
+      proof(cases rule:h_n.waiting_esE)
+        case 1
+        with waiting(1,2)
+        show ?thesis
+        by (unfold h_n.waiting_set_eq h_n.holding_set_eq s_RAG_def, 
+             fold waiting_eq, auto)
+      next
+        case 2
+        with waiting(1,2)
+        show ?thesis
+         by (unfold h_n.waiting_set_eq h_n.holding_set_eq s_RAG_def, 
+             fold waiting_eq, auto)
+      qed
+    next
+      case True
+      interpret h_e: valid_trace_v_e s e th cs
+        by (unfold_locales, insert True, simp)
+      from waiting(3)
+      show ?thesis
+      proof(cases rule:h_e.waiting_esE)
+        case 1
+        with waiting(1,2)
+        show ?thesis
+        by (unfold h_e.waiting_set_eq h_e.holding_set_eq s_RAG_def, 
+             fold waiting_eq, auto)
+      qed
+    qed
+  next
+    case (holding th' cs')
+    show ?thesis
+    proof(cases "rest = []")
+      case False
+      interpret h_n: valid_trace_v_n s e th cs
+        by (unfold_locales, insert False, simp)
+      from holding(3)
+      show ?thesis
+      proof(cases rule:h_n.holding_esE)
+        case 1
+        with holding(1,2)
+        show ?thesis
+        by (unfold h_n.waiting_set_eq h_n.holding_set_eq s_RAG_def, 
+             fold waiting_eq, auto)
+      next
+        case 2
+        with holding(1,2)
+        show ?thesis
+         by (unfold h_n.waiting_set_eq h_n.holding_set_eq s_RAG_def, 
+             fold holding_eq, auto)
+      qed
+    next
+      case True
+      interpret h_e: valid_trace_v_e s e th cs
+        by (unfold_locales, insert True, simp)
+      from holding(3)
+      show ?thesis
+      proof(cases rule:h_e.holding_esE)
+        case 1
+        with holding(1,2)
+        show ?thesis
+        by (unfold h_e.waiting_set_eq h_e.holding_set_eq s_RAG_def, 
+             fold holding_eq, auto)
+      qed
+    qed
+  qed
+next
+  fix n1 n2
+  assume h: "(n1, n2) \<in> ?R"
+  show "(n1, n2) \<in> ?L"
+  proof(cases "rest = []")
+    case False
+    interpret h_n: valid_trace_v_n s e th cs
+        by (unfold_locales, insert False, simp)
+    from h[unfolded h_n.waiting_set_eq h_n.holding_set_eq]
+    have "((n1, n2) \<in> RAG s \<and> (n1 \<noteq> Cs cs \<or> n2 \<noteq> Th th)
+                            \<and> (n1 \<noteq> Th h_n.taker \<or> n2 \<noteq> Cs cs)) \<or> 
+          (n2 = Th h_n.taker \<and> n1 = Cs cs)" 
+      by auto
+   thus ?thesis
+   proof
+      assume "n2 = Th h_n.taker \<and> n1 = Cs cs"
+      with h_n.holding_taker
+      show ?thesis 
+        by (unfold s_RAG_def, fold holding_eq, auto)
+   next
+    assume h: "(n1, n2) \<in> RAG s \<and>
+        (n1 \<noteq> Cs cs \<or> n2 \<noteq> Th th) \<and> (n1 \<noteq> Th h_n.taker \<or> n2 \<noteq> Cs cs)"
+    hence "(n1, n2) \<in> RAG s" by simp
+    thus ?thesis
+    proof(cases rule:in_RAG_E)
+      case (waiting th' cs')
+      from h and this(1,2)
+      have "th' \<noteq> h_n.taker \<or> cs' \<noteq> cs" by auto
+      hence "waiting (e#s) th' cs'" 
+      proof
+        assume "cs' \<noteq> cs"
+        from waiting_esI1[OF waiting(3) this] 
+        show ?thesis .
+      next
+        assume neq_th': "th' \<noteq> h_n.taker"
+        show ?thesis
+        proof(cases "cs' = cs")
+          case False
+          from waiting_esI1[OF waiting(3) this] 
+          show ?thesis .
+        next
+          case True
+          from h_n.waiting_esI2[OF waiting(3)[unfolded True] neq_th', folded True]
+          show ?thesis .
+        qed
+      qed
+      thus ?thesis using waiting(1,2)
+        by (unfold s_RAG_def, fold waiting_eq, auto)
+    next
+      case (holding th' cs')
+      from h this(1,2)
+      have "cs' \<noteq> cs \<or> th' \<noteq> th" by auto
+      hence "holding (e#s) th' cs'"
+      proof
+        assume "cs' \<noteq> cs"
+        from holding_esI2[OF this holding(3)] 
+        show ?thesis .
+      next
+        assume "th' \<noteq> th"
+        from holding_esI1[OF holding(3) this]
+        show ?thesis .
+      qed
+      thus ?thesis using holding(1,2)
+        by (unfold s_RAG_def, fold holding_eq, auto)
+    qed
+   qed
+ next
+   case True
+   interpret h_e: valid_trace_v_e s e th cs
+        by (unfold_locales, insert True, simp)
+   from h[unfolded h_e.waiting_set_eq h_e.holding_set_eq]
+   have h_s: "(n1, n2) \<in> RAG s" "(n1, n2) \<noteq> (Cs cs, Th th)" 
+      by auto
+   from h_s(1)
+   show ?thesis
+   proof(cases rule:in_RAG_E)
+    case (waiting th' cs')
+    from h_e.waiting_esI2[OF this(3)]
+    show ?thesis using waiting(1,2)
+      by (unfold s_RAG_def, fold waiting_eq, auto)
+   next
+    case (holding th' cs')
+    with h_s(2)
+    have "cs' \<noteq> cs \<or> th' \<noteq> th" by auto
+    thus ?thesis
+    proof
+      assume neq_cs: "cs' \<noteq> cs"
+      from holding_esI2[OF this holding(3)]
+      show ?thesis using holding(1,2)
+        by (unfold s_RAG_def, fold holding_eq, auto)
+    next
+      assume "th' \<noteq> th"
+      from holding_esI1[OF holding(3) this]
+      show ?thesis using holding(1,2)
+        by (unfold s_RAG_def, fold holding_eq, auto)
+    qed
+   qed
+ qed
+qed
+
+end
+
+lemma step_RAG_v: 
+assumes vt:
+  "vt (V th cs#s)"
+shows "
+  RAG (V th cs # s) =
+  RAG s - {(Cs cs, Th th)} -
+  {(Th th', Cs cs) |th'. next_th s th cs th'} \<union>
+  {(Cs cs, Th th') |th'.  next_th s th cs th'}" (is "?L = ?R")
+proof -
+  interpret vt_v: valid_trace_v s "V th cs"
+    using assms step_back_vt by (unfold_locales, auto) 
+  show ?thesis using vt_v.RAG_es .
+qed
+
+lemma (in valid_trace_create)
+  th_not_in_threads: "th \<notin> threads s"
+proof -
+  from pip_e[unfolded is_create]
+  show ?thesis by (cases, simp)
+qed
+
+lemma (in valid_trace_create)
+  threads_es [simp]: "threads (e#s) = threads s \<union> {th}"
+  by (unfold is_create, simp)
+
+lemma (in valid_trace_exit)
+  threads_es [simp]: "threads (e#s) = threads s - {th}"
+  by (unfold is_exit, simp)
+
+lemma (in valid_trace_p)
+  threads_es [simp]: "threads (e#s) = threads s"
+  by (unfold is_p, simp)
+
+lemma (in valid_trace_v)
+  threads_es [simp]: "threads (e#s) = threads s"
+  by (unfold is_v, simp)
+
+lemma (in valid_trace_v)
+  th_not_in_rest[simp]: "th \<notin> set rest"
+proof
+  assume otherwise: "th \<in> set rest"
+  have "distinct (wq s cs)" by (simp add: wq_distinct)
+  from this[unfolded wq_s_cs] and otherwise
+  show False by auto
+qed
+
+lemma (in valid_trace_v)
+  set_wq_es_cs [simp]: "set (wq (e#s) cs) = set (wq s cs) - {th}"
+proof(unfold wq_es_cs wq'_def, rule someI2)
+  show "distinct rest \<and> set rest = set rest"
+    by (simp add: distinct_rest)
+next
+  fix x
+  assume "distinct x \<and> set x = set rest"
+  thus "set x = set (wq s cs) - {th}" 
+      by (unfold wq_s_cs, simp)
+qed
+
+lemma (in valid_trace_exit)
+  th_not_in_wq: "th \<notin> set (wq s cs)"
+proof -
+  from pip_e[unfolded is_exit]
+  show ?thesis
+  by (cases, unfold holdents_def s_holding_def, fold wq_def, 
+             auto elim!:runing_wqE)
+qed
+
+lemma (in valid_trace) wq_threads: 
+  assumes "th \<in> set (wq s cs)"
+  shows "th \<in> threads s"
+  using assms
+proof(induct rule:ind)
+  case (Nil)
+  thus ?case by (auto simp:wq_def)
+next
+  case (Cons s e)
+  interpret vt_e: valid_trace_e s e using Cons by simp
+  show ?case
+  proof(cases e)
+    case (Create th' prio')
+    interpret vt: valid_trace_create s e th' prio'
+      using Create by (unfold_locales, simp)
+    show ?thesis
+      using Cons.hyps(2) Cons.prems by auto
+  next
+    case (Exit th')
+    interpret vt: valid_trace_exit s e th'
+      using Exit by (unfold_locales, simp)
+    show ?thesis
+      using Cons.hyps(2) Cons.prems vt.th_not_in_wq by auto 
+  next
+    case (P th' cs')
+    interpret vt: valid_trace_p s e th' cs'
+      using P by (unfold_locales, simp)
+    show ?thesis
+      using Cons.hyps(2) Cons.prems readys_threads 
+        runing_ready vt.is_p vt.runing_th_s vt_e.wq_in_inv 
+        by fastforce 
+  next
+    case (V th' cs')
+    interpret vt: valid_trace_v s e th' cs'
+      using V by (unfold_locales, simp)
+    show ?thesis using Cons
+      using vt.is_v vt.threads_es vt_e.wq_in_inv by blast
+  next
+    case (Set th' prio)
+    interpret vt: valid_trace_set s e th' prio
+      using Set by (unfold_locales, simp)
+    show ?thesis using Cons.hyps(2) Cons.prems vt.is_set 
+        by (auto simp:wq_def Let_def)
+  qed
+qed 
+
+context valid_trace
+begin
+
+lemma  dm_RAG_threads:
+  assumes in_dom: "(Th th) \<in> Domain (RAG s)"
+  shows "th \<in> threads s"
+proof -
+  from in_dom obtain n where "(Th th, n) \<in> RAG s" by auto
+  moreover from RAG_target_th[OF this] obtain cs where "n = Cs cs" by auto
+  ultimately have "(Th th, Cs cs) \<in> RAG s" by simp
+  hence "th \<in> set (wq s cs)"
+    by (unfold s_RAG_def, auto simp:cs_waiting_def)
+  from wq_threads [OF this] show ?thesis .
+qed
+
+lemma rg_RAG_threads: 
+  assumes "(Th th) \<in> Range (RAG s)"
+  shows "th \<in> threads s"
+  using assms
+  by (unfold s_RAG_def cs_waiting_def cs_holding_def, 
+       auto intro:wq_threads)
+
+lemma RAG_threads:
+  assumes "(Th th) \<in> Field (RAG s)"
+  shows "th \<in> threads s"
+  using assms
+  by (metis Field_def UnE dm_RAG_threads rg_RAG_threads)
+
+end
+
+lemma (in valid_trace_v)
+  preced_es [simp]: "preced th (e#s) = preced th s"
+  by (unfold is_v preced_def, simp)
+
+lemma the_preced_v[simp]: "the_preced (V th cs#s) = the_preced s"
+proof
+  fix th'
+  show "the_preced (V th cs # s) th' = the_preced s th'"
+    by (unfold the_preced_def preced_def, simp)
+qed
+
+lemma (in valid_trace_v)
+  the_preced_es: "the_preced (e#s) = the_preced s"
+  by (unfold is_v preced_def, simp)
+
+context valid_trace_p
+begin
+
+lemma not_holding_s_th_cs: "\<not> holding s th cs"
+proof
+  assume otherwise: "holding s th cs"
+  from pip_e[unfolded is_p]
+  show False
+  proof(cases)
+    case (thread_P)
+    moreover have "(Cs cs, Th th) \<in> RAG s"
+      using otherwise cs_holding_def 
+            holding_eq th_not_in_wq by auto
+    ultimately show ?thesis by auto
+  qed
+qed
+
+lemma waiting_kept:
+  assumes "waiting s th' cs'"
+  shows "waiting (e#s) th' cs'"
+  using assms
+  by (metis cs_waiting_def hd_append2 list.sel(1) list.set_intros(2) 
+      rotate1.simps(2) self_append_conv2 set_rotate1 
+        th_not_in_wq waiting_eq wq_es_cs wq_neq_simp)
+  
+lemma holding_kept:
+  assumes "holding s th' cs'"
+  shows "holding (e#s) th' cs'"
+proof(cases "cs' = cs")
+  case False
+  hence "wq (e#s) cs' = wq s cs'" by simp
+  with assms show ?thesis using cs_holding_def holding_eq by auto 
+next
+  case True
+  from assms[unfolded s_holding_def, folded wq_def]
+  obtain rest where eq_wq: "wq s cs' = th'#rest"
+    by (metis empty_iff list.collapse list.set(1)) 
+  hence "wq (e#s) cs' = th'#(rest@[th])"
+    by (simp add: True wq_es_cs) 
+  thus ?thesis
+    by (simp add: cs_holding_def holding_eq) 
+qed
+
+end
+
+locale valid_trace_p_h = valid_trace_p +
+  assumes we: "wq s cs = []"
+
+locale valid_trace_p_w = valid_trace_p +
+  assumes wne: "wq s cs \<noteq> []"
+begin
+
+definition "holder = hd (wq s cs)"
+definition "waiters = tl (wq s cs)"
+definition "waiters' = waiters @ [th]"
+
+lemma wq_s_cs: "wq s cs = holder#waiters"
+    by (simp add: holder_def waiters_def wne)
+    
+lemma wq_es_cs': "wq (e#s) cs = holder#waiters@[th]"
+  by (simp add: wq_es_cs wq_s_cs)
+
+lemma waiting_es_th_cs: "waiting (e#s) th cs"
+  using cs_waiting_def th_not_in_wq waiting_eq wq_es_cs' wq_s_cs by auto
+
+lemma RAG_edge: "(Th th, Cs cs) \<in> RAG (e#s)"
+   by (unfold s_RAG_def, fold waiting_eq, insert waiting_es_th_cs, auto)
+
+lemma holding_esE:
+  assumes "holding (e#s) th' cs'"
+  obtains "holding s th' cs'"
+  using assms 
+proof(cases "cs' = cs")
+  case False
+  hence "wq (e#s) cs' = wq s cs'" by simp
+  with assms show ?thesis
+    using cs_holding_def holding_eq that by auto 
+next
+  case True
+  with assms show ?thesis
+  by (metis cs_holding_def holding_eq list.sel(1) list.set_intros(1) that 
+        wq_es_cs' wq_s_cs) 
+qed
+
+lemma waiting_esE:
+  assumes "waiting (e#s) th' cs'"
+  obtains "th' \<noteq> th" "waiting s th' cs'"
+     |  "th' = th" "cs' = cs"
+proof(cases "waiting s th' cs'")
+  case True
+  have "th' \<noteq> th"
+  proof
+    assume otherwise: "th' = th"
+    from True[unfolded this]
+    show False by (simp add: th_not_waiting) 
+  qed
+  from that(1)[OF this True] show ?thesis .
+next
+  case False
+  hence "th' = th \<and> cs' = cs"
+      by (metis assms cs_waiting_def holder_def list.sel(1) rotate1.simps(2) 
+        set_ConsD set_rotate1 waiting_eq wq_es_cs wq_es_cs' wq_neq_simp)
+  with that(2) show ?thesis by metis
+qed
+
+lemma RAG_es: "RAG (e # s) =  RAG s \<union> {(Th th, Cs cs)}" (is "?L = ?R")
+proof(rule rel_eqI)
+  fix n1 n2
+  assume "(n1, n2) \<in> ?L"
+  thus "(n1, n2) \<in> ?R" 
+  proof(cases rule:in_RAG_E)
+    case (waiting th' cs')
+    from this(3)
+    show ?thesis
+    proof(cases rule:waiting_esE)
+      case 1
+      thus ?thesis using waiting(1,2)
+        by (unfold s_RAG_def, fold waiting_eq, auto)
+    next
+      case 2
+      thus ?thesis using waiting(1,2) by auto
+    qed
+  next
+    case (holding th' cs')
+    from this(3)
+    show ?thesis
+    proof(cases rule:holding_esE)
+      case 1
+      with holding(1,2)
+      show ?thesis by (unfold s_RAG_def, fold holding_eq, auto)
+    qed
+  qed
+next
+  fix n1 n2
+  assume "(n1, n2) \<in> ?R"
+  hence "(n1, n2) \<in> RAG s \<or> (n1 = Th th \<and> n2 = Cs cs)" by auto
+  thus "(n1, n2) \<in> ?L"
+  proof
+    assume "(n1, n2) \<in> RAG s"
+    thus ?thesis
+    proof(cases rule:in_RAG_E)
+      case (waiting th' cs')
+      from waiting_kept[OF this(3)]
+      show ?thesis using waiting(1,2)
+         by (unfold s_RAG_def, fold waiting_eq, auto)
+    next
+      case (holding th' cs')
+      from holding_kept[OF this(3)]
+      show ?thesis using holding(1,2)
+         by (unfold s_RAG_def, fold holding_eq, auto)
+    qed
+  next
+    assume "n1 = Th th \<and> n2 = Cs cs"
+    thus ?thesis using RAG_edge by auto
+  qed
+qed
+
+end
+
+context valid_trace_p_h
+begin
+
+lemma wq_es_cs': "wq (e#s) cs = [th]"
+  using wq_es_cs[unfolded we] by simp
+
+lemma holding_es_th_cs: 
+  shows "holding (e#s) th cs"
+proof -
+  from wq_es_cs'
+  have "th \<in> set (wq (e#s) cs)" "th = hd (wq (e#s) cs)" by auto
+  thus ?thesis using cs_holding_def holding_eq by blast 
+qed
+
+lemma RAG_edge: "(Cs cs, Th th) \<in> RAG (e#s)"
+  by (unfold s_RAG_def, fold holding_eq, insert holding_es_th_cs, auto)
+
+lemma waiting_esE:
+  assumes "waiting (e#s) th' cs'"
+  obtains "waiting s th' cs'"
+  using assms
+  by (metis cs_waiting_def event.distinct(15) is_p list.sel(1) 
+        set_ConsD waiting_eq we wq_es_cs' wq_neq_simp wq_out_inv)
+  
+lemma holding_esE:
+  assumes "holding (e#s) th' cs'"
+  obtains "cs' \<noteq> cs" "holding s th' cs'"
+    | "cs' = cs" "th' = th"
+proof(cases "cs' = cs")
+  case True
+  from held_unique[OF holding_es_th_cs assms[unfolded True]]
+  have "th' = th" by simp
+  from that(2)[OF True this] show ?thesis .
+next
+  case False
+  have "holding s th' cs'" using assms
+    using False cs_holding_def holding_eq by auto
+  from that(1)[OF False this] show ?thesis .
+qed
+
+lemma RAG_es: "RAG (e # s) =  RAG s \<union> {(Cs cs, Th th)}" (is "?L = ?R")
+proof(rule rel_eqI)
+  fix n1 n2
+  assume "(n1, n2) \<in> ?L"
+  thus "(n1, n2) \<in> ?R" 
+  proof(cases rule:in_RAG_E)
+    case (waiting th' cs')
+    from this(3)
+    show ?thesis
+    proof(cases rule:waiting_esE)
+      case 1
+      thus ?thesis using waiting(1,2)
+        by (unfold s_RAG_def, fold waiting_eq, auto)
+    qed
+  next
+    case (holding th' cs')
+    from this(3)
+    show ?thesis
+    proof(cases rule:holding_esE)
+      case 1
+      with holding(1,2)
+      show ?thesis by (unfold s_RAG_def, fold holding_eq, auto)
+    next
+      case 2
+      with holding(1,2) show ?thesis by auto
+    qed
+  qed
+next
+  fix n1 n2
+  assume "(n1, n2) \<in> ?R"
+  hence "(n1, n2) \<in> RAG s \<or> (n1 = Cs cs \<and> n2 = Th th)" by auto
+  thus "(n1, n2) \<in> ?L"
+  proof
+    assume "(n1, n2) \<in> RAG s"
+    thus ?thesis
+    proof(cases rule:in_RAG_E)
+      case (waiting th' cs')
+      from waiting_kept[OF this(3)]
+      show ?thesis using waiting(1,2)
+         by (unfold s_RAG_def, fold waiting_eq, auto)
+    next
+      case (holding th' cs')
+      from holding_kept[OF this(3)]
+      show ?thesis using holding(1,2)
+         by (unfold s_RAG_def, fold holding_eq, auto)
+    qed
+  next
+    assume "n1 = Cs cs \<and> n2 = Th th"
+    with holding_es_th_cs
+    show ?thesis 
+      by (unfold s_RAG_def, fold holding_eq, auto)
+  qed
+qed
+
+end
+
+context valid_trace_p
+begin
+
+lemma RAG_es': "RAG (e # s) =  (if (wq s cs = []) then RAG s \<union> {(Cs cs, Th th)}
+                                                  else RAG s \<union> {(Th th, Cs cs)})"
+proof(cases "wq s cs = []")
+  case True
+  interpret vt_p: valid_trace_p_h using True
+    by (unfold_locales, simp)
+  show ?thesis by (simp add: vt_p.RAG_es vt_p.we) 
+next
+  case False
+  interpret vt_p: valid_trace_p_w using False
+    by (unfold_locales, simp)
+  show ?thesis by (simp add: vt_p.RAG_es vt_p.wne) 
+qed
+
+end
+
+lemma (in valid_trace_v_n) finite_waiting_set:
+  "finite {(Th th', Cs cs) |th'. next_th s th cs th'}"
+    by (simp add: waiting_set_eq)
+
+lemma (in valid_trace_v_n) finite_holding_set:
+  "finite {(Cs cs, Th th') |th'. next_th s th cs th'}"
+    by (simp add: holding_set_eq)
+
+lemma (in valid_trace_v_e) finite_waiting_set:
+  "finite {(Th th', Cs cs) |th'. next_th s th cs th'}"
+    by (simp add: waiting_set_eq)
+
+lemma (in valid_trace_v_e) finite_holding_set:
+  "finite {(Cs cs, Th th') |th'. next_th s th cs th'}"
+    by (simp add: holding_set_eq)
+
+context valid_trace_v
+begin
+
+lemma 
+  finite_RAG_kept:
+  assumes "finite (RAG s)"
+  shows "finite (RAG (e#s))"
+proof(cases "rest = []")
+  case True
+  interpret vt: valid_trace_v_e using True
+    by (unfold_locales, simp)
+  show ?thesis using assms
+    by  (unfold RAG_es vt.waiting_set_eq vt.holding_set_eq, simp)
+next
+  case False
+  interpret vt: valid_trace_v_n using False
+    by (unfold_locales, simp)
+  show ?thesis using assms
+    by  (unfold RAG_es vt.waiting_set_eq vt.holding_set_eq, simp)
+qed
+
+end
+
+context valid_trace_v_e
+begin 
+
+lemma 
+  acylic_RAG_kept:
+  assumes "acyclic (RAG s)"
+  shows "acyclic (RAG (e#s))"
+proof(rule acyclic_subset[OF assms])
+  show "RAG (e # s) \<subseteq> RAG s"
+      by (unfold RAG_es waiting_set_eq holding_set_eq, auto)
+qed
+
+end
+
+context valid_trace_v_n
+begin 
+
+lemma waiting_taker: "waiting s taker cs"
+  apply (unfold s_waiting_def, fold wq_def, unfold wq_s_cs taker_def)
+  using eq_wq' th'_in_inv wq'_def by fastforce
+
+lemma 
+  acylic_RAG_kept:
+  assumes "acyclic (RAG s)"
+  shows "acyclic (RAG (e#s))"
+proof -
+  have "acyclic ((RAG s - {(Cs cs, Th th)} - {(Th taker, Cs cs)}) \<union> 
+                 {(Cs cs, Th taker)})" (is "acyclic (?A \<union> _)")
+  proof -
+    from assms
+    have "acyclic ?A"
+       by (rule acyclic_subset, auto)
+    moreover have "(Th taker, Cs cs) \<notin> ?A^*"
+    proof
+      assume otherwise: "(Th taker, Cs cs) \<in> ?A^*"
+      hence "(Th taker, Cs cs) \<in> ?A^+"
+        by (unfold rtrancl_eq_or_trancl, auto)
+      from tranclD[OF this]
+      obtain cs' where h: "(Th taker, Cs cs') \<in> ?A" 
+                          "(Th taker, Cs cs') \<in> RAG s"
+        by (unfold s_RAG_def, auto)
+      from this(2) have "waiting s taker cs'" 
+        by (unfold s_RAG_def, fold waiting_eq, auto)
+      from waiting_unique[OF this waiting_taker]
+      have "cs' = cs" .
+      from h(1)[unfolded this] show False by auto
+    qed
+    ultimately show ?thesis by auto
+  qed
+  thus ?thesis 
+    by (unfold RAG_es waiting_set_eq holding_set_eq, simp)
+qed
+
+end
+
+context valid_trace_p_h
+begin
+
+lemma 
+  acylic_RAG_kept:
+  assumes "acyclic (RAG s)"
+  shows "acyclic (RAG (e#s))"
+proof -
+  have "acyclic (RAG s \<union> {(Cs cs, Th th)})" (is "acyclic (?A \<union> _)") 
+  proof -
+    from assms
+    have "acyclic ?A"
+       by (rule acyclic_subset, auto)
+    moreover have "(Th th, Cs cs) \<notin> ?A^*"
+    proof
+      assume otherwise: "(Th th, Cs cs) \<in> ?A^*"
+      hence "(Th th, Cs cs) \<in> ?A^+"
+        by (unfold rtrancl_eq_or_trancl, auto)
+      from tranclD[OF this]
+      obtain cs' where h: "(Th th, Cs cs') \<in> RAG s"
+        by (unfold s_RAG_def, auto)
+      hence "waiting s th cs'" 
+        by (unfold s_RAG_def, fold waiting_eq, auto)
+      with th_not_waiting show False by auto
+    qed
+    ultimately show ?thesis by auto
+  qed
+  thus ?thesis by (unfold RAG_es, simp)
+qed
+
+end
+
+context valid_trace_p_w
+begin
+
+lemma 
+  acylic_RAG_kept:
+  assumes "acyclic (RAG s)"
+  shows "acyclic (RAG (e#s))"
+proof -
+  have "acyclic (RAG s \<union> {(Th th, Cs cs)})" (is "acyclic (?A \<union> _)") 
+  proof -
+    from assms
+    have "acyclic ?A"
+       by (rule acyclic_subset, auto)
+    moreover have "(Cs cs, Th th) \<notin> ?A^*"
+    proof
+      assume otherwise: "(Cs cs, Th th) \<in> ?A^*"
+      from pip_e[unfolded is_p]
+      show False
+      proof(cases)
+        case (thread_P)
+        moreover from otherwise have "(Cs cs, Th th) \<in> ?A^+"
+            by (unfold rtrancl_eq_or_trancl, auto)
+        ultimately show ?thesis by auto
+      qed
+    qed
+    ultimately show ?thesis by auto
+  qed
+  thus ?thesis by (unfold RAG_es, simp)
+qed
+
+end
+
+context valid_trace
+begin
+
+lemma finite_RAG:
+  shows "finite (RAG s)"
+proof(induct rule:ind)
+  case Nil
+  show ?case 
+  by (auto simp: s_RAG_def cs_waiting_def 
+                   cs_holding_def wq_def acyclic_def)
+next
+  case (Cons s e)
+  interpret vt_e: valid_trace_e s e using Cons by simp
+  show ?case
+  proof(cases e)
+    case (Create th prio)
+    interpret vt: valid_trace_create s e th prio using Create
+      by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt.RAG_unchanged) 
+  next
+    case (Exit th)
+    interpret vt: valid_trace_exit s e th using Exit
+      by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt.RAG_unchanged)
+  next
+    case (P th cs)
+    interpret vt: valid_trace_p s e th cs using P
+      by (unfold_locales, simp)
+    show ?thesis using Cons using vt.RAG_es' by auto 
+  next
+    case (V th cs)
+    interpret vt: valid_trace_v s e th cs using V
+      by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt.finite_RAG_kept) 
+  next
+    case (Set th prio)
+    interpret vt: valid_trace_set s e th prio using Set
+      by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt.RAG_unchanged) 
+  qed
+qed
+
+lemma acyclic_RAG:
+  shows "acyclic (RAG s)"
+proof(induct rule:ind)
+  case Nil
+  show ?case 
+  by (auto simp: s_RAG_def cs_waiting_def 
+                   cs_holding_def wq_def acyclic_def)
+next
+  case (Cons s e)
+  interpret vt_e: valid_trace_e s e using Cons by simp
+  show ?case
+  proof(cases e)
+    case (Create th prio)
+    interpret vt: valid_trace_create s e th prio using Create
+      by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt.RAG_unchanged) 
+  next
+    case (Exit th)
+    interpret vt: valid_trace_exit s e th using Exit
+      by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt.RAG_unchanged)
+  next
+    case (P th cs)
+    interpret vt: valid_trace_p s e th cs using P
+      by (unfold_locales, simp)
+    show ?thesis
+    proof(cases "wq s cs = []")
+      case True
+      then interpret vt_h: valid_trace_p_h s e th cs
+        by (unfold_locales, simp)
+      show ?thesis using Cons by (simp add: vt_h.acylic_RAG_kept) 
+    next
+      case False
+      then interpret vt_w: valid_trace_p_w s e th cs
+        by (unfold_locales, simp)
+      show ?thesis using Cons by (simp add: vt_w.acylic_RAG_kept) 
+    qed
+  next
+    case (V th cs)
+    interpret vt: valid_trace_v s e th cs using V
+      by (unfold_locales, simp)
+    show ?thesis
+    proof(cases "vt.rest = []")
+      case True
+      then interpret vt_e: valid_trace_v_e s e th cs
+        by (unfold_locales, simp)
+      show ?thesis by (simp add: Cons.hyps(2) vt_e.acylic_RAG_kept) 
+    next
+      case False
+      then interpret vt_n: valid_trace_v_n s e th cs
+        by (unfold_locales, simp)
+      show ?thesis by (simp add: Cons.hyps(2) vt_n.acylic_RAG_kept) 
+    qed
+  next
+    case (Set th prio)
+    interpret vt: valid_trace_set s e th prio using Set
+      by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt.RAG_unchanged) 
+  qed
+qed
+
+lemma wf_RAG: "wf (RAG s)"
+proof(rule finite_acyclic_wf)
+  from finite_RAG show "finite (RAG s)" .
+next
+  from acyclic_RAG show "acyclic (RAG s)" .
+qed
+
+lemma sgv_wRAG: "single_valued (wRAG s)"
+  using waiting_unique
+  by (unfold single_valued_def wRAG_def, auto)
+
+lemma sgv_hRAG: "single_valued (hRAG s)"
+  using held_unique 
+  by (unfold single_valued_def hRAG_def, auto)
+
+lemma sgv_tRAG: "single_valued (tRAG s)"
+  by (unfold tRAG_def, rule single_valued_relcomp, 
+              insert sgv_wRAG sgv_hRAG, auto)
+
+lemma acyclic_tRAG: "acyclic (tRAG s)"
+proof(unfold tRAG_def, rule acyclic_compose)
+  show "acyclic (RAG s)" using acyclic_RAG .
+next
+  show "wRAG s \<subseteq> RAG s" unfolding RAG_split by auto
+next
+  show "hRAG s \<subseteq> RAG s" unfolding RAG_split by auto
+qed
+
+lemma unique_RAG: "\<lbrakk>(n, n1) \<in> RAG s; (n, n2) \<in> RAG s\<rbrakk> \<Longrightarrow> n1 = n2"
+  apply(unfold s_RAG_def, auto, fold waiting_eq holding_eq)
+  by(auto elim:waiting_unique held_unique)
+
+lemma sgv_RAG: "single_valued (RAG s)"
+  using unique_RAG by (auto simp:single_valued_def)
+
+lemma rtree_RAG: "rtree (RAG s)"
+  using sgv_RAG acyclic_RAG
+  by (unfold rtree_def rtree_axioms_def sgv_def, auto)
+
+end
+
+sublocale valid_trace < rtree_RAG: rtree "RAG s"
+proof
+  show "single_valued (RAG s)"
+  apply (intro_locales)
+    by (unfold single_valued_def, 
+        auto intro:unique_RAG)
+
+  show "acyclic (RAG s)"
+     by (rule acyclic_RAG)
+qed
+
+sublocale valid_trace < rtree_s: rtree "tRAG s"
+proof(unfold_locales)
+  from sgv_tRAG show "single_valued (tRAG s)" .
+next
+  from acyclic_tRAG show "acyclic (tRAG s)" .
+qed
+
+sublocale valid_trace < fsbtRAGs : fsubtree "RAG s"
+proof -
+  show "fsubtree (RAG s)"
+  proof(intro_locales)
+    show "fbranch (RAG s)" using finite_fbranchI[OF finite_RAG] .
+  next
+    show "fsubtree_axioms (RAG s)"
+    proof(unfold fsubtree_axioms_def)
+      from wf_RAG show "wf (RAG s)" .
+    qed
+  qed
+qed
+
+lemma tRAG_alt_def: 
+  "tRAG s = {(Th th1, Th th2) | th1 th2. 
+                  \<exists> cs. (Th th1, Cs cs) \<in> RAG s \<and> (Cs cs, Th th2) \<in> RAG s}"
+ by (auto simp:tRAG_def RAG_split wRAG_def hRAG_def)
+
+sublocale valid_trace < fsbttRAGs: fsubtree "tRAG s"
+proof -
+  have "fsubtree (tRAG s)"
+  proof -
+    have "fbranch (tRAG s)"
+    proof(unfold tRAG_def, rule fbranch_compose)
+        show "fbranch (wRAG s)"
+        proof(rule finite_fbranchI)
+           from finite_RAG show "finite (wRAG s)"
+           by (unfold RAG_split, auto)
+        qed
+    next
+        show "fbranch (hRAG s)"
+        proof(rule finite_fbranchI)
+           from finite_RAG 
+           show "finite (hRAG s)" by (unfold RAG_split, auto)
+        qed
+    qed
+    moreover have "wf (tRAG s)"
+    proof(rule wf_subset)
+      show "wf (RAG s O RAG s)" using wf_RAG
+        by (fold wf_comp_self, simp)
+    next
+      show "tRAG s \<subseteq> (RAG s O RAG s)"
+        by (unfold tRAG_alt_def, auto)
+    qed
+    ultimately show ?thesis
+      by (unfold fsubtree_def fsubtree_axioms_def,auto)
+  qed
+  from this[folded tRAG_def] show "fsubtree (tRAG s)" .
+qed
+
+
+context valid_trace
+begin
+
+lemma finite_subtree_threads:
+    "finite {th'. Th th' \<in> subtree (RAG s) (Th th)}" (is "finite ?A")
+proof -
+  have "?A = the_thread ` {Th th' | th' . Th th' \<in> subtree (RAG s) (Th th)}"
+        by (auto, insert image_iff, fastforce)
+  moreover have "finite {Th th' | th' . Th th' \<in> subtree (RAG s) (Th th)}"
+        (is "finite ?B")
+  proof -
+     have "?B = (subtree (RAG s) (Th th)) \<inter> {Th th' | th'. True}"
+      by auto
+     moreover have "... \<subseteq> (subtree (RAG s) (Th th))" by auto
+     moreover have "finite ..." by (simp add: fsbtRAGs.finite_subtree) 
+     ultimately show ?thesis by auto
+  qed
+  ultimately show ?thesis by auto
+qed
+
+lemma le_cp:
+  shows "preced th s \<le> cp s th"
+  proof(unfold cp_alt_def, rule Max_ge)
+    show "finite (the_preced s ` {th'. Th th' \<in> subtree (RAG s) (Th th)})"
+      by (simp add: finite_subtree_threads)
+  next
+    show "preced th s \<in> the_preced s ` {th'. Th th' \<in> subtree (RAG s) (Th th)}"
+      by (simp add: subtree_def the_preced_def)   
+  qed
+
+lemma cp_le:
+  assumes th_in: "th \<in> threads s"
+  shows "cp s th \<le> Max (the_preced s ` threads s)"
+proof(unfold cp_alt_def, rule Max_f_mono)
+  show "finite (threads s)" by (simp add: finite_threads) 
+next
+  show " {th'. Th th' \<in> subtree (RAG s) (Th th)} \<noteq> {}"
+    using subtree_def by fastforce
+next
+  show "{th'. Th th' \<in> subtree (RAG s) (Th th)} \<subseteq> threads s"
+    using assms
+    by (smt Domain.DomainI dm_RAG_threads mem_Collect_eq 
+        node.inject(1) rtranclD subsetI subtree_def trancl_domain) 
+qed
+
+lemma max_cp_eq: 
+  shows "Max ((cp s) ` threads s) = Max (the_preced s ` threads s)"
+  (is "?L = ?R")
+proof -
+  have "?L \<le> ?R" 
+  proof(cases "threads s = {}")
+    case False
+    show ?thesis 
+      by (rule Max.boundedI, 
+          insert cp_le, 
+          auto simp:finite_threads False)
+  qed auto
+  moreover have "?R \<le> ?L"
+    by (rule Max_fg_mono, 
+        simp add: finite_threads,
+        simp add: le_cp the_preced_def)
+  ultimately show ?thesis by auto
+qed
+
+lemma max_cp_eq_the_preced:
+  shows "Max ((cp s) ` threads s) = Max (the_preced s ` threads s)"
+  using max_cp_eq using the_preced_def by presburger 
+
+lemma wf_RAG_converse: 
+  shows "wf ((RAG s)^-1)"
+proof(rule finite_acyclic_wf_converse)
+  from finite_RAG 
+  show "finite (RAG s)" .
+next
+  from acyclic_RAG
+  show "acyclic (RAG s)" .
+qed
+
+lemma chain_building:
+  assumes "node \<in> Domain (RAG s)"
+  obtains th' where "th' \<in> readys s" "(node, Th th') \<in> (RAG s)^+"
+proof -
+  from assms have "node \<in> Range ((RAG s)^-1)" by auto
+  from wf_base[OF wf_RAG_converse this]
+  obtain b where h_b: "(b, node) \<in> ((RAG s)\<inverse>)\<^sup>+" "\<forall>c. (c, b) \<notin> (RAG s)\<inverse>" by auto
+  obtain th' where eq_b: "b = Th th'"
+  proof(cases b)
+    case (Cs cs)
+    from h_b(1)[unfolded trancl_converse] 
+    have "(node, b) \<in> ((RAG s)\<^sup>+)" by auto
+    from tranclE[OF this]
+    obtain n where "(n, b) \<in> RAG s" by auto
+    from this[unfolded Cs]
+    obtain th1 where "waiting s th1 cs"
+      by (unfold s_RAG_def, fold waiting_eq, auto)
+    from waiting_holding[OF this]
+    obtain th2 where "holding s th2 cs" .
+    hence "(Cs cs, Th th2) \<in> RAG s"
+      by (unfold s_RAG_def, fold holding_eq, auto)
+    with h_b(2)[unfolded Cs, rule_format]
+    have False by auto
+    thus ?thesis by auto
+  qed auto
+  have "th' \<in> readys s" 
+  proof -
+    from h_b(2)[unfolded eq_b]
+    have "\<forall>cs. \<not> waiting s th' cs"
+      by (unfold s_RAG_def, fold waiting_eq, auto)
+    moreover have "th' \<in> threads s"
+    proof(rule rg_RAG_threads)
+      from tranclD[OF h_b(1), unfolded eq_b]
+      obtain z where "(z, Th th') \<in> (RAG s)" by auto
+      thus "Th th' \<in> Range (RAG s)" by auto
+    qed
+    ultimately show ?thesis by (auto simp:readys_def)
+  qed
+  moreover have "(node, Th th') \<in> (RAG s)^+" 
+    using h_b(1)[unfolded trancl_converse] eq_b by auto
+  ultimately show ?thesis using that by metis
+qed
+
+text {* \noindent
+  The following is just an instance of @{text "chain_building"}.
+*}
+lemma th_chain_to_ready:
+  assumes th_in: "th \<in> threads s"
+  shows "th \<in> readys s \<or> (\<exists> th'. th' \<in> readys s \<and> (Th th, Th th') \<in> (RAG 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 (RAG s)" 
+    by (auto simp:readys_def s_waiting_def s_RAG_def wq_def cs_waiting_def Domain_def)
+  from chain_building [rule_format, OF this]
+  show ?thesis by auto
+qed
+
+end
+
+lemma count_rec1 [simp]: 
+  assumes "Q e"
+  shows "count Q (e#es) = Suc (count Q es)"
+  using assms
+  by (unfold count_def, auto)
+
+lemma count_rec2 [simp]: 
+  assumes "\<not>Q e"
+  shows "count Q (e#es) = (count Q es)"
+  using assms
+  by (unfold count_def, auto)
+
+lemma count_rec3 [simp]: 
+  shows "count Q [] =  0"
+  by (unfold count_def, auto)
+
+lemma cntP_simp1[simp]:
+  "cntP (P th cs'#s) th = cntP s th + 1"
+  by (unfold cntP_def, simp)
+
+lemma cntP_simp2[simp]:
+  assumes "th' \<noteq> th"
+  shows "cntP (P th cs'#s) th' = cntP s th'"
+  using assms
+  by (unfold cntP_def, simp)
+
+lemma cntP_simp3[simp]:
+  assumes "\<not> isP e"
+  shows "cntP (e#s) th' = cntP s th'"
+  using assms
+  by (unfold cntP_def, cases e, simp+)
+
+lemma cntV_simp1[simp]:
+  "cntV (V th cs'#s) th = cntV s th + 1"
+  by (unfold cntV_def, simp)
+
+lemma cntV_simp2[simp]:
+  assumes "th' \<noteq> th"
+  shows "cntV (V th cs'#s) th' = cntV s th'"
+  using assms
+  by (unfold cntV_def, simp)
+
+lemma cntV_simp3[simp]:
+  assumes "\<not> isV e"
+  shows "cntV (e#s) th' = cntV s th'"
+  using assms
+  by (unfold cntV_def, cases e, simp+)
+
+lemma cntP_diff_inv:
+  assumes "cntP (e#s) th \<noteq> cntP s th"
+  shows "isP e \<and> actor e = th"
+proof(cases e)
+  case (P th' pty)
+  show ?thesis
+  by (cases "(\<lambda>e. \<exists>cs. e = P th cs) (P th' pty)", 
+        insert assms P, auto simp:cntP_def)
+qed (insert assms, auto simp:cntP_def)
+  
+lemma cntV_diff_inv:
+  assumes "cntV (e#s) th \<noteq> cntV s th"
+  shows "isV e \<and> actor e = th"
+proof(cases e)
+  case (V th' pty)
+  show ?thesis
+  by (cases "(\<lambda>e. \<exists>cs. e = V th cs) (V th' pty)", 
+        insert assms V, auto simp:cntV_def)
+qed (insert assms, auto simp:cntV_def)
+
+lemma children_RAG_alt_def:
+  "children (RAG (s::state)) (Th th) = Cs ` {cs. holding s th cs}"
+  by (unfold s_RAG_def, auto simp:children_def holding_eq)
+
+lemma holdents_alt_def:
+  "holdents s th = the_cs ` (children (RAG (s::state)) (Th th))"
+  by (unfold children_RAG_alt_def holdents_def, simp add: image_image)
+
+lemma cntCS_alt_def:
+  "cntCS s th = card (children (RAG s) (Th th))"
+  apply (unfold children_RAG_alt_def cntCS_def holdents_def)
+  by (rule card_image[symmetric], auto simp:inj_on_def)
+
+context valid_trace
+begin
+
+lemma finite_holdents: "finite (holdents s th)"
+  by (unfold holdents_alt_def, insert fsbtRAGs.finite_children, auto)
+  
+end
+
+context valid_trace_p_w
+begin
+
+lemma holding_s_holder: "holding s holder cs"
+  by (unfold s_holding_def, fold wq_def, unfold wq_s_cs, auto)
+
+lemma holding_es_holder: "holding (e#s) holder cs"
+  by (unfold s_holding_def, fold wq_def, unfold wq_es_cs wq_s_cs, auto)
+
+lemma holdents_es:
+  shows "holdents (e#s) th' = holdents s th'" (is "?L = ?R") 
+proof -
+  { fix cs'
+    assume "cs' \<in> ?L"
+    hence h: "holding (e#s) th' cs'" by (auto simp:holdents_def)
+    have "holding s th' cs'"
+    proof(cases "cs' = cs")
+      case True
+      from held_unique[OF h[unfolded True] holding_es_holder]
+      have "th' = holder" .
+      thus ?thesis 
+        by (unfold True holdents_def, insert holding_s_holder, simp)
+    next
+      case False
+      hence "wq (e#s) cs' = wq s cs'" by simp
+      from h[unfolded s_holding_def, folded wq_def, unfolded this]
+      show ?thesis
+       by (unfold s_holding_def, fold wq_def, auto)
+    qed 
+    hence "cs' \<in> ?R" by (auto simp:holdents_def)
+  } moreover {
+    fix cs'
+    assume "cs' \<in> ?R"
+    hence h: "holding s th' cs'" by (auto simp:holdents_def)
+    have "holding (e#s) th' cs'"
+    proof(cases "cs' = cs")
+      case True
+      from held_unique[OF h[unfolded True] holding_s_holder]
+      have "th' = holder" .
+      thus ?thesis 
+        by (unfold True holdents_def, insert holding_es_holder, simp)
+    next
+      case False
+      hence "wq s cs' = wq (e#s) cs'" by simp
+      from h[unfolded s_holding_def, folded wq_def, unfolded this]
+      show ?thesis
+       by (unfold s_holding_def, fold wq_def, auto)
+    qed 
+    hence "cs' \<in> ?L" by (auto simp:holdents_def)
+  } ultimately show ?thesis by auto
+qed
+
+lemma cntCS_es_th[simp]: "cntCS (e#s) th' = cntCS s th'"
+ by (unfold cntCS_def holdents_es, simp)
+
+lemma th_not_ready_es: 
+  shows "th \<notin> readys (e#s)"
+  using waiting_es_th_cs 
+  by (unfold readys_def, auto)
+
+end
+  
+context valid_trace_p_h
+begin
+
+lemma th_not_waiting':
+  "\<not> waiting (e#s) th cs'"
+proof(cases "cs' = cs")
+  case True
+  show ?thesis
+    by (unfold True s_waiting_def, fold wq_def, unfold wq_es_cs', auto)
+next
+  case False
+  from th_not_waiting[of cs', unfolded s_waiting_def, folded wq_def]
+  show ?thesis
+    by (unfold s_waiting_def, fold wq_def, insert False, simp)
+qed
+
+lemma ready_th_es: 
+  shows "th \<in> readys (e#s)"
+  using th_not_waiting'
+  by (unfold readys_def, insert live_th_es, auto)
+
+lemma holdents_es_th:
+  "holdents (e#s) th = (holdents s th) \<union> {cs}" (is "?L = ?R")
+proof -
+  { fix cs'
+    assume "cs' \<in> ?L" 
+    hence "holding (e#s) th cs'"
+      by (unfold holdents_def, auto)
+    hence "cs' \<in> ?R"
+     by (cases rule:holding_esE, auto simp:holdents_def)
+  } moreover {
+    fix cs'
+    assume "cs' \<in> ?R"
+    hence "holding s th cs' \<or> cs' = cs" 
+      by (auto simp:holdents_def)
+    hence "cs' \<in> ?L"
+    proof
+      assume "holding s th cs'"
+      from holding_kept[OF this]
+      show ?thesis by (auto simp:holdents_def)
+    next
+      assume "cs' = cs"
+      thus ?thesis using holding_es_th_cs
+        by (unfold holdents_def, auto)
+    qed
+  } ultimately show ?thesis by auto
+qed
+
+lemma cntCS_es_th: "cntCS (e#s) th = cntCS s th + 1"
+proof -
+  have "card (holdents s th \<union> {cs}) = card (holdents s th) + 1"
+  proof(subst card_Un_disjoint)
+    show "holdents s th \<inter> {cs} = {}"
+      using not_holding_s_th_cs by (auto simp:holdents_def)
+  qed (auto simp:finite_holdents)
+  thus ?thesis
+   by (unfold cntCS_def holdents_es_th, simp)
+qed
+
+lemma no_holder: 
+  "\<not> holding s th' cs"
+proof
+  assume otherwise: "holding s th' cs"
+  from this[unfolded s_holding_def, folded wq_def, unfolded we]
+  show False by auto
+qed
+
+lemma holdents_es_th':
+  assumes "th' \<noteq> th"
+  shows "holdents (e#s) th' = holdents s th'" (is "?L = ?R")
+proof -
+  { fix cs'
+    assume "cs' \<in> ?L"
+    hence h_e: "holding (e#s) th' cs'" by (auto simp:holdents_def)
+    have "cs' \<noteq> cs"
+    proof
+      assume "cs' = cs"
+      from held_unique[OF h_e[unfolded this] holding_es_th_cs]
+      have "th' = th" .
+      with assms show False by simp
+    qed
+    from h_e[unfolded s_holding_def, folded wq_def, unfolded wq_neq_simp[OF this]]
+    have "th' \<in> set (wq s cs') \<and> th' = hd (wq s cs')" .
+    hence "cs' \<in> ?R" 
+      by (unfold holdents_def s_holding_def, fold wq_def, auto)
+  } moreover {
+    fix cs'
+    assume "cs' \<in> ?R"
+    hence "holding s th' cs'" by (auto simp:holdents_def)
+    from holding_kept[OF this]
+    have "holding (e # s) th' cs'" .
+    hence "cs' \<in> ?L"
+      by (unfold holdents_def, auto)
+  } ultimately show ?thesis by auto
+qed
+
+lemma cntCS_es_th'[simp]: 
+  assumes "th' \<noteq> th"
+  shows "cntCS (e#s) th' = cntCS s th'"
+  by (unfold cntCS_def holdents_es_th'[OF assms], simp)
+
+end
+
+context valid_trace_p
+begin
+
+lemma readys_kept1: 
+  assumes "th' \<noteq> th"
+  and "th' \<in> readys (e#s)"
+  shows "th' \<in> readys s"
+proof -
+  { fix cs'
+    assume wait: "waiting s th' cs'"
+    have n_wait: "\<not> waiting (e#s) th' cs'" 
+        using assms(2)[unfolded readys_def] by auto
+    have False
+    proof(cases "cs' = cs")
+      case False
+      with n_wait wait
+      show ?thesis 
+        by (unfold s_waiting_def, fold wq_def, auto)
+    next
+      case True
+      show ?thesis
+      proof(cases "wq s cs = []")
+        case True
+        then interpret vt: valid_trace_p_h
+          by (unfold_locales, simp)
+        show ?thesis using n_wait wait waiting_kept by auto 
+      next
+        case False
+        then interpret vt: valid_trace_p_w by (unfold_locales, simp)
+        show ?thesis using n_wait wait waiting_kept by blast 
+      qed
+    qed
+  } with assms(2) show ?thesis  
+    by (unfold readys_def, auto)
+qed
+
+lemma readys_kept2: 
+  assumes "th' \<noteq> th"
+  and "th' \<in> readys s"
+  shows "th' \<in> readys (e#s)"
+proof -
+  { fix cs'
+    assume wait: "waiting (e#s) th' cs'"
+    have n_wait: "\<not> waiting s th' cs'" 
+        using assms(2)[unfolded readys_def] by auto
+    have False
+    proof(cases "cs' = cs")
+      case False
+      with n_wait wait
+      show ?thesis 
+        by (unfold s_waiting_def, fold wq_def, auto)
+    next
+      case True
+      show ?thesis
+      proof(cases "wq s cs = []")
+        case True
+        then interpret vt: valid_trace_p_h
+          by (unfold_locales, simp)
+        show ?thesis using n_wait vt.waiting_esE wait by blast 
+      next
+        case False
+        then interpret vt: valid_trace_p_w by (unfold_locales, simp)
+        show ?thesis using assms(1) n_wait vt.waiting_esE wait by auto 
+      qed
+    qed
+  } with assms(2) show ?thesis  
+    by (unfold readys_def, auto)
+qed
+
+lemma readys_simp [simp]:
+  assumes "th' \<noteq> th"
+  shows "(th' \<in> readys (e#s)) = (th' \<in> readys s)"
+  using readys_kept1[OF assms] readys_kept2[OF assms]
+  by metis
+
+lemma cnp_cnv_cncs_kept: (* ddd *)
+  assumes "cntP s th' = cntV s th' + cntCS s th' + pvD s th'"
+  shows "cntP (e#s) th' = cntV (e#s) th' +  cntCS (e#s) th' + pvD (e#s) th'"
+proof(cases "th' = th")
+  case True
+  note eq_th' = this
+  show ?thesis
+  proof(cases "wq s cs = []")
+    case True
+    then interpret vt: valid_trace_p_h by (unfold_locales, simp)
+    show ?thesis
+      using assms eq_th' is_p ready_th_s vt.cntCS_es_th vt.ready_th_es pvD_def by auto 
+  next
+    case False
+    then interpret vt: valid_trace_p_w by (unfold_locales, simp)
+    show ?thesis
+      using add.commute add.left_commute assms eq_th' is_p live_th_s 
+            ready_th_s vt.th_not_ready_es pvD_def
+      apply (auto)
+      by (fold is_p, simp)
+  qed
+next
+  case False
+  note h_False = False
+  thus ?thesis
+  proof(cases "wq s cs = []")
+    case True
+    then interpret vt: valid_trace_p_h by (unfold_locales, simp)
+    show ?thesis using assms
+      by (insert True h_False pvD_def, auto split:if_splits,unfold is_p, auto)
+  next
+    case False
+    then interpret vt: valid_trace_p_w by (unfold_locales, simp)
+    show ?thesis using assms
+      by (insert False h_False pvD_def, auto split:if_splits,unfold is_p, auto)
+  qed
+qed
+
+end
+
+
+context valid_trace_v (* ccc *)
+begin
+
+lemma holding_th_cs_s: 
+  "holding s th cs" 
+ by  (unfold s_holding_def, fold wq_def, unfold wq_s_cs, auto)
+
+lemma th_ready_s [simp]: "th \<in> readys s"
+  using runing_th_s
+  by (unfold runing_def readys_def, auto)
+
+lemma th_live_s [simp]: "th \<in> threads s"
+  using th_ready_s by (unfold readys_def, auto)
+
+lemma th_ready_es [simp]: "th \<in> readys (e#s)"
+  using runing_th_s neq_t_th
+  by (unfold is_v runing_def readys_def, auto)
+
+lemma th_live_es [simp]: "th \<in> threads (e#s)"
+  using th_ready_es by (unfold readys_def, auto)
+
+lemma pvD_th_s[simp]: "pvD s th = 0"
+  by (unfold pvD_def, simp)
+
+lemma pvD_th_es[simp]: "pvD (e#s) th = 0"
+  by (unfold pvD_def, simp)
+
+lemma cntCS_s_th [simp]: "cntCS s th > 0"
+proof -
+  have "cs \<in> holdents s th" using holding_th_cs_s
+    by (unfold holdents_def, simp)
+  moreover have "finite (holdents s th)" using finite_holdents
+    by simp
+  ultimately show ?thesis
+    by (unfold cntCS_def, 
+        auto intro!:card_gt_0_iff[symmetric, THEN iffD1])
+qed
+
+end
+
+context valid_trace_v_n
+begin
+
+lemma not_ready_taker_s[simp]: 
+  "taker \<notin> readys s"
+  using waiting_taker
+  by (unfold readys_def, auto)
+
+lemma taker_live_s [simp]: "taker \<in> threads s"
+proof -
+  have "taker \<in> set wq'" by (simp add: eq_wq') 
+  from th'_in_inv[OF this]
+  have "taker \<in> set rest" .
+  hence "taker \<in> set (wq s cs)" by (simp add: wq_s_cs) 
+  thus ?thesis using wq_threads by auto 
+qed
+
+lemma taker_live_es [simp]: "taker \<in> threads (e#s)"
+  using taker_live_s threads_es by blast
+
+lemma taker_ready_es [simp]:
+  shows "taker \<in> readys (e#s)"
+proof -
+  { fix cs'
+    assume "waiting (e#s) taker cs'"
+    hence False
+    proof(cases rule:waiting_esE)
+      case 1
+      thus ?thesis using waiting_taker waiting_unique by auto 
+    qed simp
+  } thus ?thesis by (unfold readys_def, auto)
+qed
+
+lemma neq_taker_th: "taker \<noteq> th"
+  using th_not_waiting waiting_taker by blast
+
+lemma not_holding_taker_s_cs:
+  shows "\<not> holding s taker cs"
+  using holding_cs_eq_th neq_taker_th by auto
+
+lemma holdents_es_taker:
+  "holdents (e#s) taker = holdents s taker \<union> {cs}" (is "?L = ?R")
+proof -
+  { fix cs'
+    assume "cs' \<in> ?L"
+    hence "holding (e#s) taker cs'" by (auto simp:holdents_def)
+    hence "cs' \<in> ?R"
+    proof(cases rule:holding_esE)
+      case 2
+      thus ?thesis by (auto simp:holdents_def)
+    qed auto
+  } moreover {
+    fix cs'
+    assume "cs' \<in> ?R"
+    hence "holding s taker cs' \<or> cs' = cs" by (auto simp:holdents_def)
+    hence "cs' \<in> ?L" 
+    proof
+      assume "holding s taker cs'"
+      hence "holding (e#s) taker cs'" 
+          using holding_esI2 holding_taker by fastforce 
+      thus ?thesis by (auto simp:holdents_def)
+    next
+      assume "cs' = cs"
+      with holding_taker
+      show ?thesis by (auto simp:holdents_def)
+    qed
+  } ultimately show ?thesis by auto
+qed
+
+lemma cntCS_es_taker [simp]: "cntCS (e#s) taker = cntCS s taker + 1"
+proof -
+  have "card (holdents s taker \<union> {cs}) = card (holdents s taker) + 1"
+  proof(subst card_Un_disjoint)
+    show "holdents s taker \<inter> {cs} = {}"
+      using not_holding_taker_s_cs by (auto simp:holdents_def)
+  qed (auto simp:finite_holdents)
+  thus ?thesis 
+    by (unfold cntCS_def, insert holdents_es_taker, simp)
+qed
+
+lemma pvD_taker_s[simp]: "pvD s taker = 1"
+  by (unfold pvD_def, simp)
+
+lemma pvD_taker_es[simp]: "pvD (e#s) taker = 0"
+  by (unfold pvD_def, simp)  
+
+lemma pvD_th_s[simp]: "pvD s th = 0"
+  by (unfold pvD_def, simp)
+
+lemma pvD_th_es[simp]: "pvD (e#s) th = 0"
+  by (unfold pvD_def, simp)
+
+lemma holdents_es_th:
+  "holdents (e#s) th = holdents s th - {cs}" (is "?L = ?R")
+proof -
+  { fix cs'
+    assume "cs' \<in> ?L"
+    hence "holding (e#s) th cs'" by (auto simp:holdents_def)
+    hence "cs' \<in> ?R"
+    proof(cases rule:holding_esE)
+      case 2
+      thus ?thesis by (auto simp:holdents_def)
+    qed (insert neq_taker_th, auto)
+  } moreover {
+    fix cs'
+    assume "cs' \<in> ?R"
+    hence "cs' \<noteq> cs" "holding s th cs'" by (auto simp:holdents_def)
+    from holding_esI2[OF this]
+    have "cs' \<in> ?L" by (auto simp:holdents_def)
+  } ultimately show ?thesis by auto
+qed
+
+lemma cntCS_es_th [simp]: "cntCS (e#s) th = cntCS s th - 1"
+proof -
+  have "card (holdents s th - {cs}) = card (holdents s th) - 1"
+  proof -
+    have "cs \<in> holdents s th" using holding_th_cs_s
+      by (auto simp:holdents_def)
+    moreover have "finite (holdents s th)"
+        by (simp add: finite_holdents) 
+    ultimately show ?thesis by auto
+  qed
+  thus ?thesis by (unfold cntCS_def holdents_es_th)
+qed
+
+lemma holdents_kept:
+  assumes "th' \<noteq> taker"
+  and "th' \<noteq> th"
+  shows "holdents (e#s) th' = holdents s th'" (is "?L = ?R")
+proof -
+  { fix cs'
+    assume h: "cs' \<in> ?L"
+    have "cs' \<in> ?R"
+    proof(cases "cs' = cs")
+      case False
+      hence eq_wq: "wq (e#s) cs' = wq s cs'" by simp
+      from h have "holding (e#s) th' cs'" by (auto simp:holdents_def)
+      from this[unfolded s_holding_def, folded wq_def, unfolded eq_wq]
+      show ?thesis
+        by (unfold holdents_def s_holding_def, fold wq_def, auto)
+    next
+      case True
+      from h[unfolded this]
+      have "holding (e#s) th' cs" by (auto simp:holdents_def)
+      from held_unique[OF this holding_taker]
+      have "th' = taker" .
+      with assms show ?thesis by auto
+    qed
+  } moreover {
+    fix cs'
+    assume h: "cs' \<in> ?R"
+    have "cs' \<in> ?L"
+    proof(cases "cs' = cs")
+      case False
+      hence eq_wq: "wq (e#s) cs' = wq s cs'" by simp
+      from h have "holding s th' cs'" by (auto simp:holdents_def)
+      from this[unfolded s_holding_def, folded wq_def, unfolded eq_wq]
+      show ?thesis
+        by (unfold holdents_def s_holding_def, fold wq_def, insert eq_wq, simp)
+    next
+      case True
+      from h[unfolded this]
+      have "holding s th' cs" by (auto simp:holdents_def)
+      from held_unique[OF this holding_th_cs_s]
+      have "th' = th" .
+      with assms show ?thesis by auto
+    qed
+  } ultimately show ?thesis by auto
+qed
+
+lemma cntCS_kept [simp]:
+  assumes "th' \<noteq> taker"
+  and "th' \<noteq> th"
+  shows "cntCS (e#s) th' = cntCS s th'"
+  by (unfold cntCS_def holdents_kept[OF assms], simp)
+
+lemma readys_kept1: 
+  assumes "th' \<noteq> taker"
+  and "th' \<in> readys (e#s)"
+  shows "th' \<in> readys s"
+proof -
+  { fix cs'
+    assume wait: "waiting s th' cs'"
+    have n_wait: "\<not> waiting (e#s) th' cs'" 
+        using assms(2)[unfolded readys_def] by auto
+    have False
+    proof(cases "cs' = cs")
+      case False
+      with n_wait wait
+      show ?thesis 
+        by (unfold s_waiting_def, fold wq_def, auto)
+    next
+      case True
+      have "th' \<in> set (th # rest) \<and> th' \<noteq> hd (th # rest)" 
+        using wait[unfolded True s_waiting_def, folded wq_def, unfolded wq_s_cs] .
+      moreover have "\<not> (th' \<in> set rest \<and> th' \<noteq> hd (taker # rest'))" 
+        using n_wait[unfolded True s_waiting_def, folded wq_def, 
+                    unfolded wq_es_cs set_wq', unfolded eq_wq'] .
+      ultimately have "th' = taker" by auto
+      with assms(1)
+      show ?thesis by simp
+    qed
+  } with assms(2) show ?thesis  
+    by (unfold readys_def, auto)
+qed
+
+lemma readys_kept2: 
+  assumes "th' \<noteq> taker"
+  and "th' \<in> readys s"
+  shows "th' \<in> readys (e#s)"
+proof -
+  { fix cs'
+    assume wait: "waiting (e#s) th' cs'"
+    have n_wait: "\<not> waiting s th' cs'" 
+        using assms(2)[unfolded readys_def] by auto
+    have False
+    proof(cases "cs' = cs")
+      case False
+      with n_wait wait
+      show ?thesis 
+        by (unfold s_waiting_def, fold wq_def, auto)
+    next
+      case True
+      have "th' \<in> set rest \<and> th' \<noteq> hd (taker # rest')"
+          using  wait [unfolded True s_waiting_def, folded wq_def, 
+                    unfolded wq_es_cs set_wq', unfolded eq_wq']  .
+      moreover have "\<not> (th' \<in> set (th # rest) \<and> th' \<noteq> hd (th # rest))"
+          using n_wait[unfolded True s_waiting_def, folded wq_def, unfolded wq_s_cs] .
+      ultimately have "th' = taker" by auto
+      with assms(1)
+      show ?thesis by simp
+    qed
+  } with assms(2) show ?thesis  
+    by (unfold readys_def, auto)
+qed
+
+lemma readys_simp [simp]:
+  assumes "th' \<noteq> taker"
+  shows "(th' \<in> readys (e#s)) = (th' \<in> readys s)"
+  using readys_kept1[OF assms] readys_kept2[OF assms]
+  by metis
+
+lemma cnp_cnv_cncs_kept:
+  assumes "cntP s th' = cntV s th' + cntCS s th' + pvD s th'"
+  shows "cntP (e#s) th' = cntV (e#s) th' +  cntCS (e#s) th' + pvD (e#s) th'"
+proof -
+  { assume eq_th': "th' = taker"
+    have ?thesis
+      apply (unfold eq_th' pvD_taker_es cntCS_es_taker)
+      by (insert neq_taker_th assms[unfolded eq_th'], unfold is_v, simp)
+  } moreover {
+    assume eq_th': "th' = th"
+    have ?thesis 
+      apply (unfold eq_th' pvD_th_es cntCS_es_th)
+      by (insert assms[unfolded eq_th'], unfold is_v, simp)
+  } moreover {
+    assume h: "th' \<noteq> taker" "th' \<noteq> th"
+    have ?thesis using assms
+      apply (unfold cntCS_kept[OF h], insert h, unfold is_v, simp)
+      by (fold is_v, unfold pvD_def, simp)
+  } ultimately show ?thesis by metis
+qed
+
+end
+
+context valid_trace_v_e
+begin
+
+lemma holdents_es_th:
+  "holdents (e#s) th = holdents s th - {cs}" (is "?L = ?R")
+proof -
+  { fix cs'
+    assume "cs' \<in> ?L"
+    hence "holding (e#s) th cs'" by (auto simp:holdents_def)
+    hence "cs' \<in> ?R"
+    proof(cases rule:holding_esE)
+      case 1
+      thus ?thesis by (auto simp:holdents_def)
+    qed 
+  } moreover {
+    fix cs'
+    assume "cs' \<in> ?R"
+    hence "cs' \<noteq> cs" "holding s th cs'" by (auto simp:holdents_def)
+    from holding_esI2[OF this]
+    have "cs' \<in> ?L" by (auto simp:holdents_def)
+  } ultimately show ?thesis by auto
+qed
+
+lemma cntCS_es_th [simp]: "cntCS (e#s) th = cntCS s th - 1"
+proof -
+  have "card (holdents s th - {cs}) = card (holdents s th) - 1"
+  proof -
+    have "cs \<in> holdents s th" using holding_th_cs_s
+      by (auto simp:holdents_def)
+    moreover have "finite (holdents s th)"
+        by (simp add: finite_holdents) 
+    ultimately show ?thesis by auto
+  qed
+  thus ?thesis by (unfold cntCS_def holdents_es_th)
+qed
+
+lemma holdents_kept:
+  assumes "th' \<noteq> th"
+  shows "holdents (e#s) th' = holdents s th'" (is "?L = ?R")
+proof -
+  { fix cs'
+    assume h: "cs' \<in> ?L"
+    have "cs' \<in> ?R"
+    proof(cases "cs' = cs")
+      case False
+      hence eq_wq: "wq (e#s) cs' = wq s cs'" by simp
+      from h have "holding (e#s) th' cs'" by (auto simp:holdents_def)
+      from this[unfolded s_holding_def, folded wq_def, unfolded eq_wq]
+      show ?thesis
+        by (unfold holdents_def s_holding_def, fold wq_def, auto)
+    next
+      case True
+      from h[unfolded this]
+      have "holding (e#s) th' cs" by (auto simp:holdents_def)
+      from this[unfolded s_holding_def, folded wq_def, 
+            unfolded wq_es_cs nil_wq']
+      show ?thesis by auto
+    qed
+  } moreover {
+    fix cs'
+    assume h: "cs' \<in> ?R"
+    have "cs' \<in> ?L"
+    proof(cases "cs' = cs")
+      case False
+      hence eq_wq: "wq (e#s) cs' = wq s cs'" by simp
+      from h have "holding s th' cs'" by (auto simp:holdents_def)
+      from this[unfolded s_holding_def, folded wq_def, unfolded eq_wq]
+      show ?thesis
+        by (unfold holdents_def s_holding_def, fold wq_def, insert eq_wq, simp)
+    next
+      case True
+      from h[unfolded this]
+      have "holding s th' cs" by (auto simp:holdents_def)
+      from held_unique[OF this holding_th_cs_s]
+      have "th' = th" .
+      with assms show ?thesis by auto
+    qed
+  } ultimately show ?thesis by auto
+qed
+
+lemma cntCS_kept [simp]:
+  assumes "th' \<noteq> th"
+  shows "cntCS (e#s) th' = cntCS s th'"
+  by (unfold cntCS_def holdents_kept[OF assms], simp)
+
+lemma readys_kept1: 
+  assumes "th' \<in> readys (e#s)"
+  shows "th' \<in> readys s"
+proof -
+  { fix cs'
+    assume wait: "waiting s th' cs'"
+    have n_wait: "\<not> waiting (e#s) th' cs'" 
+        using assms(1)[unfolded readys_def] by auto
+    have False
+    proof(cases "cs' = cs")
+      case False
+      with n_wait wait
+      show ?thesis 
+        by (unfold s_waiting_def, fold wq_def, auto)
+    next
+      case True
+      have "th' \<in> set (th # rest) \<and> th' \<noteq> hd (th # rest)" 
+        using wait[unfolded True s_waiting_def, folded wq_def, unfolded wq_s_cs] . 
+      hence "th' \<in> set rest" by auto
+      with set_wq' have "th' \<in> set wq'" by metis
+      with nil_wq' show ?thesis by simp
+    qed
+  } thus ?thesis using assms
+    by (unfold readys_def, auto)
+qed
+
+lemma readys_kept2: 
+  assumes "th' \<in> readys s"
+  shows "th' \<in> readys (e#s)"
+proof -
+  { fix cs'
+    assume wait: "waiting (e#s) th' cs'"
+    have n_wait: "\<not> waiting s th' cs'" 
+        using assms[unfolded readys_def] by auto
+    have False
+    proof(cases "cs' = cs")
+      case False
+      with n_wait wait
+      show ?thesis 
+        by (unfold s_waiting_def, fold wq_def, auto)
+    next
+      case True
+      have "th' \<in> set [] \<and> th' \<noteq> hd []"
+        using wait[unfolded True s_waiting_def, folded wq_def, 
+              unfolded wq_es_cs nil_wq'] .
+      thus ?thesis by simp
+    qed
+  } with assms show ?thesis  
+    by (unfold readys_def, auto)
+qed
+
+lemma readys_simp [simp]:
+  shows "(th' \<in> readys (e#s)) = (th' \<in> readys s)"
+  using readys_kept1[OF assms] readys_kept2[OF assms]
+  by metis
+
+lemma cnp_cnv_cncs_kept:
+  assumes "cntP s th' = cntV s th' + cntCS s th' + pvD s th'"
+  shows "cntP (e#s) th' = cntV (e#s) th' +  cntCS (e#s) th' + pvD (e#s) th'"
+proof -
+  {
+    assume eq_th': "th' = th"
+    have ?thesis 
+      apply (unfold eq_th' pvD_th_es cntCS_es_th)
+      by (insert assms[unfolded eq_th'], unfold is_v, simp)
+  } moreover {
+    assume h: "th' \<noteq> th"
+    have ?thesis using assms
+      apply (unfold cntCS_kept[OF h], insert h, unfold is_v, simp)
+      by (fold is_v, unfold pvD_def, simp)
+  } ultimately show ?thesis by metis
+qed
+
+end
+
+context valid_trace_v
+begin
+
+lemma cnp_cnv_cncs_kept:
+  assumes "cntP s th' = cntV s th' + cntCS s th' + pvD s th'"
+  shows "cntP (e#s) th' = cntV (e#s) th' +  cntCS (e#s) th' + pvD (e#s) th'"
+proof(cases "rest = []")
+  case True
+  then interpret vt: valid_trace_v_e by (unfold_locales, simp)
+  show ?thesis using assms using vt.cnp_cnv_cncs_kept by blast 
+next
+  case False
+  then interpret vt: valid_trace_v_n by (unfold_locales, simp)
+  show ?thesis using assms using vt.cnp_cnv_cncs_kept by blast 
+qed
+
+end
+
+context valid_trace_create
+begin
+
+lemma th_not_live_s [simp]: "th \<notin> threads s"
+proof -
+  from pip_e[unfolded is_create]
+  show ?thesis by (cases, simp)
+qed
+
+lemma th_not_ready_s [simp]: "th \<notin> readys s"
+  using th_not_live_s by (unfold readys_def, simp)
+
+lemma th_live_es [simp]: "th \<in> threads (e#s)"
+  by (unfold is_create, simp)
+
+lemma not_waiting_th_s [simp]: "\<not> waiting s th cs'"
+proof
+  assume "waiting s th cs'"
+  from this[unfolded s_waiting_def, folded wq_def, unfolded wq_neq_simp]
+  have "th \<in> set (wq s cs')" by auto
+  from wq_threads[OF this] have "th \<in> threads s" .
+  with th_not_live_s show False by simp
+qed
+
+lemma not_holding_th_s [simp]: "\<not> holding s th cs'"
+proof
+  assume "holding s th cs'"
+  from this[unfolded s_holding_def, folded wq_def, unfolded wq_neq_simp]
+  have "th \<in> set (wq s cs')" by auto
+  from wq_threads[OF this] have "th \<in> threads s" .
+  with th_not_live_s show False by simp
+qed
+
+lemma not_waiting_th_es [simp]: "\<not> waiting (e#s) th cs'"
+proof
+  assume "waiting (e # s) th cs'"
+  from this[unfolded s_waiting_def, folded wq_def, unfolded wq_neq_simp]
+  have "th \<in> set (wq s cs')" by auto
+  from wq_threads[OF this] have "th \<in> threads s" .
+  with th_not_live_s show False by simp
+qed
+
+lemma not_holding_th_es [simp]: "\<not> holding (e#s) th cs'"
+proof
+  assume "holding (e # s) th cs'"
+  from this[unfolded s_holding_def, folded wq_def, unfolded wq_neq_simp]
+  have "th \<in> set (wq s cs')" by auto
+  from wq_threads[OF this] have "th \<in> threads s" .
+  with th_not_live_s show False by simp
+qed
+
+lemma ready_th_es [simp]: "th \<in> readys (e#s)"
+  by (simp add:readys_def)
+
+lemma holdents_th_s: "holdents s th = {}"
+  by (unfold holdents_def, auto)
+
+lemma holdents_th_es: "holdents (e#s) th = {}"
+  by (unfold holdents_def, auto)
+
+lemma cntCS_th_s [simp]: "cntCS s th = 0"
+  by (unfold cntCS_def, simp add:holdents_th_s)
+
+lemma cntCS_th_es [simp]: "cntCS (e#s) th = 0"
+  by (unfold cntCS_def, simp add:holdents_th_es)
+
+lemma pvD_th_s [simp]: "pvD s th = 0"
+  by (unfold pvD_def, simp)
+
+lemma pvD_th_es [simp]: "pvD (e#s) th = 0"
+  by (unfold pvD_def, simp)
+
+lemma holdents_kept:
+  assumes "th' \<noteq> th"
+  shows "holdents (e#s) th' = holdents s th'" (is "?L = ?R")
+proof -
+  { fix cs'
+    assume h: "cs' \<in> ?L"
+    hence "cs' \<in> ?R"
+      by (unfold holdents_def s_holding_def, fold wq_def, 
+             unfold wq_neq_simp, auto)
+  } moreover {
+    fix cs'
+    assume h: "cs' \<in> ?R"
+    hence "cs' \<in> ?L"
+      by (unfold holdents_def s_holding_def, fold wq_def, 
+             unfold wq_neq_simp, auto)
+  } ultimately show ?thesis by auto
+qed
+
+lemma cntCS_kept [simp]:
+  assumes "th' \<noteq> th"
+  shows "cntCS (e#s) th' = cntCS s th'" (is "?L = ?R")
+  using holdents_kept[OF assms]
+  by (unfold cntCS_def, simp)
+
+lemma readys_kept1: 
+  assumes "th' \<noteq> th"
+  and "th' \<in> readys (e#s)"
+  shows "th' \<in> readys s"
+proof -
+  { fix cs'
+    assume wait: "waiting s th' cs'"
+    have n_wait: "\<not> waiting (e#s) th' cs'" 
+      using assms by (auto simp:readys_def)
+    from wait[unfolded s_waiting_def, folded wq_def]
+         n_wait[unfolded s_waiting_def, folded wq_def, unfolded wq_neq_simp]
+    have False by auto
+  } thus ?thesis using assms
+    by (unfold readys_def, auto)
+qed
+
+lemma readys_kept2: 
+  assumes "th' \<noteq> th"
+  and "th' \<in> readys s"
+  shows "th' \<in> readys (e#s)"
+proof -
+  { fix cs'
+    assume wait: "waiting (e#s) th' cs'"
+    have n_wait: "\<not> waiting s th' cs'"
+      using assms(2) by (auto simp:readys_def)
+    from wait[unfolded s_waiting_def, folded wq_def, unfolded wq_neq_simp]
+         n_wait[unfolded s_waiting_def, folded wq_def]
+    have False by auto
+  } with assms show ?thesis  
+    by (unfold readys_def, auto)
+qed
+
+lemma readys_simp [simp]:
+  assumes "th' \<noteq> th"
+  shows "(th' \<in> readys (e#s)) = (th' \<in> readys s)"
+  using readys_kept1[OF assms] readys_kept2[OF assms]
+  by metis
+
+lemma pvD_kept [simp]:
+  assumes "th' \<noteq> th"
+  shows "pvD (e#s) th' = pvD s th'"
+  using assms
+  by (unfold pvD_def, simp)
+
+lemma cnp_cnv_cncs_kept:
+  assumes "cntP s th' = cntV s th' + cntCS s th' + pvD s th'"
+  shows "cntP (e#s) th' = cntV (e#s) th' +  cntCS (e#s) th' + pvD (e#s) th'"
+proof -
+  {
+    assume eq_th': "th' = th"
+    have ?thesis using assms
+      by (unfold eq_th', simp, unfold is_create, simp)
+  } moreover {
+    assume h: "th' \<noteq> th"
+    hence ?thesis using assms
+      by (simp, simp add:is_create)
+  } ultimately show ?thesis by metis
+qed
+
+end
+
+context valid_trace_exit
+begin
+
+lemma th_live_s [simp]: "th \<in> threads s"
+proof -
+  from pip_e[unfolded is_exit]
+  show ?thesis
+  by (cases, unfold runing_def readys_def, simp)
+qed
+
+lemma th_ready_s [simp]: "th \<in> readys s"
+proof -
+  from pip_e[unfolded is_exit]
+  show ?thesis
+  by (cases, unfold runing_def, simp)
+qed
+
+lemma th_not_live_es [simp]: "th \<notin> threads (e#s)"
+  by (unfold is_exit, simp)
+
+lemma not_holding_th_s [simp]: "\<not> holding s th cs'"
+proof -
+  from pip_e[unfolded is_exit]
+  show ?thesis 
+   by (cases, unfold holdents_def, auto)
+qed
+
+lemma cntCS_th_s [simp]: "cntCS s th = 0"
+proof -
+  from pip_e[unfolded is_exit]
+  show ?thesis 
+   by (cases, unfold cntCS_def, simp)
+qed
+
+lemma not_holding_th_es [simp]: "\<not> holding (e#s) th cs'"
+proof
+  assume "holding (e # s) th cs'"
+  from this[unfolded s_holding_def, folded wq_def, unfolded wq_neq_simp]
+  have "holding s th cs'" 
+    by (unfold s_holding_def, fold wq_def, auto)
+  with not_holding_th_s 
+  show False by simp
+qed
+
+lemma ready_th_es [simp]: "th \<notin> readys (e#s)"
+  by (simp add:readys_def)
+
+lemma holdents_th_s: "holdents s th = {}"
+  by (unfold holdents_def, auto)
+
+lemma holdents_th_es: "holdents (e#s) th = {}"
+  by (unfold holdents_def, auto)
+
+lemma cntCS_th_es [simp]: "cntCS (e#s) th = 0"
+  by (unfold cntCS_def, simp add:holdents_th_es)
+
+lemma pvD_th_s [simp]: "pvD s th = 0"
+  by (unfold pvD_def, simp)
+
+lemma pvD_th_es [simp]: "pvD (e#s) th = 0"
+  by (unfold pvD_def, simp)
+
+lemma holdents_kept:
+  assumes "th' \<noteq> th"
+  shows "holdents (e#s) th' = holdents s th'" (is "?L = ?R")
+proof -
+  { fix cs'
+    assume h: "cs' \<in> ?L"
+    hence "cs' \<in> ?R"
+      by (unfold holdents_def s_holding_def, fold wq_def, 
+             unfold wq_neq_simp, auto)
+  } moreover {
+    fix cs'
+    assume h: "cs' \<in> ?R"
+    hence "cs' \<in> ?L"
+      by (unfold holdents_def s_holding_def, fold wq_def, 
+             unfold wq_neq_simp, auto)
+  } ultimately show ?thesis by auto
+qed
+
+lemma cntCS_kept [simp]:
+  assumes "th' \<noteq> th"
+  shows "cntCS (e#s) th' = cntCS s th'" (is "?L = ?R")
+  using holdents_kept[OF assms]
+  by (unfold cntCS_def, simp)
+
+lemma readys_kept1: 
+  assumes "th' \<noteq> th"
+  and "th' \<in> readys (e#s)"
+  shows "th' \<in> readys s"
+proof -
+  { fix cs'
+    assume wait: "waiting s th' cs'"
+    have n_wait: "\<not> waiting (e#s) th' cs'" 
+      using assms by (auto simp:readys_def)
+    from wait[unfolded s_waiting_def, folded wq_def]
+         n_wait[unfolded s_waiting_def, folded wq_def, unfolded wq_neq_simp]
+    have False by auto
+  } thus ?thesis using assms
+    by (unfold readys_def, auto)
+qed
+
+lemma readys_kept2: 
+  assumes "th' \<noteq> th"
+  and "th' \<in> readys s"
+  shows "th' \<in> readys (e#s)"
+proof -
+  { fix cs'
+    assume wait: "waiting (e#s) th' cs'"
+    have n_wait: "\<not> waiting s th' cs'"
+      using assms(2) by (auto simp:readys_def)
+    from wait[unfolded s_waiting_def, folded wq_def, unfolded wq_neq_simp]
+         n_wait[unfolded s_waiting_def, folded wq_def]
+    have False by auto
+  } with assms show ?thesis  
+    by (unfold readys_def, auto)
+qed
+
+lemma readys_simp [simp]:
+  assumes "th' \<noteq> th"
+  shows "(th' \<in> readys (e#s)) = (th' \<in> readys s)"
+  using readys_kept1[OF assms] readys_kept2[OF assms]
+  by metis
+
+lemma pvD_kept [simp]:
+  assumes "th' \<noteq> th"
+  shows "pvD (e#s) th' = pvD s th'"
+  using assms
+  by (unfold pvD_def, simp)
+
+lemma cnp_cnv_cncs_kept:
+  assumes "cntP s th' = cntV s th' + cntCS s th' + pvD s th'"
+  shows "cntP (e#s) th' = cntV (e#s) th' +  cntCS (e#s) th' + pvD (e#s) th'"
+proof -
+  {
+    assume eq_th': "th' = th"
+    have ?thesis using assms
+      by (unfold eq_th', simp, unfold is_exit, simp)
+  } moreover {
+    assume h: "th' \<noteq> th"
+    hence ?thesis using assms
+      by (simp, simp add:is_exit)
+  } ultimately show ?thesis by metis
+qed
+
+end
+
+context valid_trace_set
+begin
+
+lemma th_live_s [simp]: "th \<in> threads s"
+proof -
+  from pip_e[unfolded is_set]
+  show ?thesis
+  by (cases, unfold runing_def readys_def, simp)
+qed
+
+lemma th_ready_s [simp]: "th \<in> readys s"
+proof -
+  from pip_e[unfolded is_set]
+  show ?thesis
+  by (cases, unfold runing_def, simp)
+qed
+
+lemma th_not_live_es [simp]: "th \<in> threads (e#s)"
+  by (unfold is_set, simp)
+
+
+lemma holdents_kept:
+  shows "holdents (e#s) th' = holdents s th'" (is "?L = ?R")
+proof -
+  { fix cs'
+    assume h: "cs' \<in> ?L"
+    hence "cs' \<in> ?R"
+      by (unfold holdents_def s_holding_def, fold wq_def, 
+             unfold wq_neq_simp, auto)
+  } moreover {
+    fix cs'
+    assume h: "cs' \<in> ?R"
+    hence "cs' \<in> ?L"
+      by (unfold holdents_def s_holding_def, fold wq_def, 
+             unfold wq_neq_simp, auto)
+  } ultimately show ?thesis by auto
+qed
+
+lemma cntCS_kept [simp]:
+  shows "cntCS (e#s) th' = cntCS s th'" (is "?L = ?R")
+  using holdents_kept
+  by (unfold cntCS_def, simp)
+
+lemma threads_kept[simp]:
+  "threads (e#s) = threads s"
+  by (unfold is_set, simp)
+
+lemma readys_kept1: 
+  assumes "th' \<in> readys (e#s)"
+  shows "th' \<in> readys s"
+proof -
+  { fix cs'
+    assume wait: "waiting s th' cs'"
+    have n_wait: "\<not> waiting (e#s) th' cs'" 
+      using assms by (auto simp:readys_def)
+    from wait[unfolded s_waiting_def, folded wq_def]
+         n_wait[unfolded s_waiting_def, folded wq_def, unfolded wq_neq_simp]
+    have False by auto
+  } moreover have "th' \<in> threads s" 
+    using assms[unfolded readys_def] by auto
+  ultimately show ?thesis 
+    by (unfold readys_def, auto)
+qed
+
+lemma readys_kept2: 
+  assumes "th' \<in> readys s"
+  shows "th' \<in> readys (e#s)"
+proof -
+  { fix cs'
+    assume wait: "waiting (e#s) th' cs'"
+    have n_wait: "\<not> waiting s th' cs'"
+      using assms by (auto simp:readys_def)
+    from wait[unfolded s_waiting_def, folded wq_def, unfolded wq_neq_simp]
+         n_wait[unfolded s_waiting_def, folded wq_def]
+    have False by auto
+  } with assms show ?thesis  
+    by (unfold readys_def, auto)
+qed
+
+lemma readys_simp [simp]:
+  shows "(th' \<in> readys (e#s)) = (th' \<in> readys s)"
+  using readys_kept1 readys_kept2
+  by metis
+
+lemma pvD_kept [simp]:
+  shows "pvD (e#s) th' = pvD s th'"
+  by (unfold pvD_def, simp)
+
+lemma cnp_cnv_cncs_kept:
+  assumes "cntP s th' = cntV s th' + cntCS s th' + pvD s th'"
+  shows "cntP (e#s) th' = cntV (e#s) th' +  cntCS (e#s) th' + pvD (e#s) th'"
+  using assms
+  by (unfold is_set, simp, fold is_set, simp)
+
+end
+
+context valid_trace
+begin
+
+lemma cnp_cnv_cncs: "cntP s th' = cntV s th' + cntCS s th' + pvD s th'"
+proof(induct rule:ind)
+  case Nil
+  thus ?case 
+    by (unfold cntP_def cntV_def pvD_def cntCS_def holdents_def 
+              s_holding_def, simp)
+next
+  case (Cons s e)
+  interpret vt_e: valid_trace_e s e using Cons by simp
+  show ?case
+  proof(cases e)
+    case (Create th prio)
+    interpret vt_create: valid_trace_create s e th prio 
+      using Create by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt_create.cnp_cnv_cncs_kept) 
+  next
+    case (Exit th)
+    interpret vt_exit: valid_trace_exit s e th  
+        using Exit by (unfold_locales, simp)
+   show ?thesis using Cons by (simp add: vt_exit.cnp_cnv_cncs_kept) 
+  next
+    case (P th cs)
+    interpret vt_p: valid_trace_p s e th cs using P by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt_p.cnp_cnv_cncs_kept) 
+  next
+    case (V th cs)
+    interpret vt_v: valid_trace_v s e th cs using V by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt_v.cnp_cnv_cncs_kept) 
+  next
+    case (Set th prio)
+    interpret vt_set: valid_trace_set s e th prio
+        using Set by (unfold_locales, simp)
+    show ?thesis using Cons by (simp add: vt_set.cnp_cnv_cncs_kept) 
+  qed
+qed
+
+lemma not_thread_holdents:
+  assumes not_in: "th \<notin> threads s" 
+  shows "holdents s th = {}"
+proof -
+  { fix cs
+    assume "cs \<in> holdents s th"
+    hence "holding s th cs" by (auto simp:holdents_def)
+    from this[unfolded s_holding_def, folded wq_def]
+    have "th \<in> set (wq s cs)" by auto
+    with wq_threads have "th \<in> threads s" by auto
+    with assms
+    have False by simp
+  } thus ?thesis by auto
+qed
+
+lemma not_thread_cncs:
+  assumes not_in: "th \<notin> threads s" 
+  shows "cntCS s th = 0"
+  using not_thread_holdents[OF assms]
+  by (simp add:cntCS_def)
+
+lemma cnp_cnv_eq:
+  assumes "th \<notin> threads s"
+  shows "cntP s th = cntV s th"
+  using assms cnp_cnv_cncs not_thread_cncs pvD_def
+  by (auto)
+
+lemma runing_unique:
+  assumes 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"
+    unfolding runing_def by auto
+  from this[unfolded cp_alt_def]
+  have eq_max: 
+    "Max (the_preced s ` {th'. Th th' \<in> subtree (RAG s) (Th th1)}) =
+     Max (the_preced s ` {th'. Th th' \<in> subtree (RAG s) (Th th2)})" 
+        (is "Max ?L = Max ?R") .
+  have "Max ?L \<in> ?L"
+  proof(rule Max_in)
+    show "finite ?L" by (simp add: finite_subtree_threads)
+  next
+    show "?L \<noteq> {}" using subtree_def by fastforce 
+  qed
+  then obtain th1' where 
+    h_1: "Th th1' \<in> subtree (RAG s) (Th th1)" "the_preced s th1' = Max ?L"
+    by auto
+  have "Max ?R \<in> ?R"
+  proof(rule Max_in)
+    show "finite ?R" by (simp add: finite_subtree_threads)
+  next
+    show "?R \<noteq> {}" using subtree_def by fastforce 
+  qed
+  then obtain th2' where 
+    h_2: "Th th2' \<in> subtree (RAG s) (Th th2)" "the_preced s th2' = Max ?R"
+    by auto
+  have "th1' = th2'"
+  proof(rule preced_unique)
+    from h_1(1)
+    show "th1' \<in> threads s"
+    proof(cases rule:subtreeE)
+      case 1
+      hence "th1' = th1" by simp
+      with runing_1 show ?thesis by (auto simp:runing_def readys_def)
+    next
+      case 2
+      from this(2)
+      have "(Th th1', Th th1) \<in> (RAG s)^+" by (auto simp:ancestors_def)
+      from tranclD[OF this]
+      have "(Th th1') \<in> Domain (RAG s)" by auto
+      from dm_RAG_threads[OF this] show ?thesis .
+    qed
+  next
+    from h_2(1)
+    show "th2' \<in> threads s"
+    proof(cases rule:subtreeE)
+      case 1
+      hence "th2' = th2" by simp
+      with runing_2 show ?thesis by (auto simp:runing_def readys_def)
+    next
+      case 2
+      from this(2)
+      have "(Th th2', Th th2) \<in> (RAG s)^+" by (auto simp:ancestors_def)
+      from tranclD[OF this]
+      have "(Th th2') \<in> Domain (RAG s)" by auto
+      from dm_RAG_threads[OF this] show ?thesis .
+    qed
+  next
+    have "the_preced s th1' = the_preced s th2'" 
+     using eq_max h_1(2) h_2(2) by metis
+    thus "preced th1' s = preced th2' s" by (simp add:the_preced_def)
+  qed
+  from h_1(1)[unfolded this]
+  have star1: "(Th th2', Th th1) \<in> (RAG s)^*" by (auto simp:subtree_def)
+  from h_2(1)[unfolded this]
+  have star2: "(Th th2', Th th2) \<in> (RAG s)^*" by (auto simp:subtree_def)
+  from star_rpath[OF star1] obtain xs1 
+    where rp1: "rpath (RAG s) (Th th2') xs1 (Th th1)"
+    by auto
+  from star_rpath[OF star2] obtain xs2 
+    where rp2: "rpath (RAG s) (Th th2') xs2 (Th th2)"
+    by auto
+  from rp1 rp2
+  show ?thesis
+  proof(cases)
+    case (less_1 xs')
+    moreover have "xs' = []"
+    proof(rule ccontr)
+      assume otherwise: "xs' \<noteq> []"
+      from rpath_plus[OF less_1(3) this]
+      have "(Th th1, Th th2) \<in> (RAG s)\<^sup>+" .
+      from tranclD[OF this]
+      obtain cs where "waiting s th1 cs"
+        by (unfold s_RAG_def, fold waiting_eq, auto)
+      with runing_1 show False
+        by (unfold runing_def readys_def, auto)
+    qed
+    ultimately have "xs2 = xs1" by simp
+    from rpath_dest_eq[OF rp1 rp2[unfolded this]]
+    show ?thesis by simp
+  next
+    case (less_2 xs')
+    moreover have "xs' = []"
+    proof(rule ccontr)
+      assume otherwise: "xs' \<noteq> []"
+      from rpath_plus[OF less_2(3) this]
+      have "(Th th2, Th th1) \<in> (RAG s)\<^sup>+" .
+      from tranclD[OF this]
+      obtain cs where "waiting s th2 cs"
+        by (unfold s_RAG_def, fold waiting_eq, auto)
+      with runing_2 show False
+        by (unfold runing_def readys_def, auto)
+    qed
+    ultimately have "xs2 = xs1" by simp
+    from rpath_dest_eq[OF rp1 rp2[unfolded this]]
+    show ?thesis by simp
+  qed
+qed
+
+lemma card_runing: "card (runing s) \<le> 1"
+proof(cases "runing s = {}")
+  case True
+  thus ?thesis by auto
+next
+  case False
+  then obtain th where [simp]: "th \<in> runing s" by auto
+  from runing_unique[OF this]
+  have "runing s = {th}" by auto
+  thus ?thesis by auto
+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 thread prio)
+    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 eq_pv_children:
+  assumes eq_pv: "cntP s th = cntV s th"
+  shows "children (RAG s) (Th th) = {}"
+proof -
+    from cnp_cnv_cncs and eq_pv
+    have "cntCS s th = 0" 
+      by (auto split:if_splits)
+    from this[unfolded cntCS_def holdents_alt_def]
+    have card_0: "card (the_cs ` children (RAG s) (Th th)) = 0" .
+    have "finite (the_cs ` children (RAG s) (Th th))"
+      by (simp add: fsbtRAGs.finite_children)
+    from card_0[unfolded card_0_eq[OF this]]
+    show ?thesis by auto
+qed
+
+lemma eq_pv_holdents:
+  assumes eq_pv: "cntP s th = cntV s th"
+  shows "holdents s th = {}"
+  by (unfold holdents_alt_def eq_pv_children[OF assms], simp)
+
+lemma eq_pv_subtree:
+  assumes eq_pv: "cntP s th = cntV s th"
+  shows "subtree (RAG s) (Th th) = {Th th}"
+  using eq_pv_children[OF assms]
+    by (unfold subtree_children, simp)
+
+end
+
+lemma cp_gen_alt_def:
+  "cp_gen s = (Max \<circ> (\<lambda>x. (the_preced s \<circ> the_thread) ` subtree (tRAG s) x))"
+    by (auto simp:cp_gen_def)
+
+lemma tRAG_nodeE:
+  assumes "(n1, n2) \<in> tRAG s"
+  obtains th1 th2 where "n1 = Th th1" "n2 = Th th2"
+  using assms
+  by (auto simp: tRAG_def wRAG_def hRAG_def tRAG_def)
+
+lemma subtree_nodeE:
+  assumes "n \<in> subtree (tRAG s) (Th th)"
+  obtains th1 where "n = Th th1"
+proof -
+  show ?thesis
+  proof(rule subtreeE[OF assms])
+    assume "n = Th th"
+    from that[OF this] show ?thesis .
+  next
+    assume "Th th \<in> ancestors (tRAG s) n"
+    hence "(n, Th th) \<in> (tRAG s)^+" by (auto simp:ancestors_def)
+    hence "\<exists> th1. n = Th th1"
+    proof(induct)
+      case (base y)
+      from tRAG_nodeE[OF this] show ?case by metis
+    next
+      case (step y z)
+      thus ?case by auto
+    qed
+    with that show ?thesis by auto
+  qed
+qed
+
+lemma tRAG_star_RAG: "(tRAG s)^* \<subseteq> (RAG s)^*"
+proof -
+  have "(wRAG s O hRAG s)^* \<subseteq> (RAG s O RAG s)^*" 
+    by (rule rtrancl_mono, auto simp:RAG_split)
+  also have "... \<subseteq> ((RAG s)^*)^*"
+    by (rule rtrancl_mono, auto)
+  also have "... = (RAG s)^*" by simp
+  finally show ?thesis by (unfold tRAG_def, simp)
+qed
+
+lemma tRAG_subtree_RAG: "subtree (tRAG s) x \<subseteq> subtree (RAG s) x"
+proof -
+  { fix a
+    assume "a \<in> subtree (tRAG s) x"
+    hence "(a, x) \<in> (tRAG s)^*" by (auto simp:subtree_def)
+    with tRAG_star_RAG
+    have "(a, x) \<in> (RAG s)^*" by auto
+    hence "a \<in> subtree (RAG s) x" by (auto simp:subtree_def)
+  } thus ?thesis by auto
+qed
+
+lemma tRAG_trancl_eq:
+   "{th'. (Th th', Th th)  \<in> (tRAG s)^+} = 
+    {th'. (Th th', Th th)  \<in> (RAG s)^+}"
+   (is "?L = ?R")
+proof -
+  { fix th'
+    assume "th' \<in> ?L"
+    hence "(Th th', Th th) \<in> (tRAG s)^+" by auto
+    from tranclD[OF this]
+    obtain z where h: "(Th th', z) \<in> tRAG s" "(z, Th th) \<in> (tRAG s)\<^sup>*" by auto
+    from tRAG_subtree_RAG and this(2)
+    have "(z, Th th) \<in> (RAG s)^*" by (meson subsetCE tRAG_star_RAG) 
+    moreover from h(1) have "(Th th', z) \<in> (RAG s)^+" using tRAG_alt_def by auto 
+    ultimately have "th' \<in> ?R"  by auto 
+  } moreover 
+  { fix th'
+    assume "th' \<in> ?R"
+    hence "(Th th', Th th) \<in> (RAG s)^+" by (auto)
+    from plus_rpath[OF this]
+    obtain xs where rp: "rpath (RAG s) (Th th') xs (Th th)" "xs \<noteq> []" by auto
+    hence "(Th th', Th th) \<in> (tRAG s)^+"
+    proof(induct xs arbitrary:th' th rule:length_induct)
+      case (1 xs th' th)
+      then obtain x1 xs1 where Cons1: "xs = x1#xs1" by (cases xs, auto)
+      show ?case
+      proof(cases "xs1")
+        case Nil
+        from 1(2)[unfolded Cons1 Nil]
+        have rp: "rpath (RAG s) (Th th') [x1] (Th th)" .
+        hence "(Th th', x1) \<in> (RAG s)" 
+          by (cases, auto)
+        then obtain cs where "x1 = Cs cs" 
+              by (unfold s_RAG_def, auto)
+        from rpath_nnl_lastE[OF rp[unfolded this]]
+        show ?thesis by auto
+      next
+        case (Cons x2 xs2)
+        from 1(2)[unfolded Cons1[unfolded this]]
+        have rp: "rpath (RAG s) (Th th') (x1 # x2 # xs2) (Th th)" .
+        from rpath_edges_on[OF this]
+        have eds: "edges_on (Th th' # x1 # x2 # xs2) \<subseteq> RAG s" .
+        have "(Th th', x1) \<in> edges_on (Th th' # x1 # x2 # xs2)"
+            by (simp add: edges_on_unfold)
+        with eds have rg1: "(Th th', x1) \<in> RAG s" by auto
+        then obtain cs1 where eq_x1: "x1 = Cs cs1" by (unfold s_RAG_def, auto)
+        have "(x1, x2) \<in> edges_on (Th th' # x1 # x2 # xs2)"
+            by (simp add: edges_on_unfold)
+        from this eds
+        have rg2: "(x1, x2) \<in> RAG s" by auto
+        from this[unfolded eq_x1] 
+        obtain th1 where eq_x2: "x2 = Th th1" by (unfold s_RAG_def, auto)
+        from rg1[unfolded eq_x1] rg2[unfolded eq_x1 eq_x2]
+        have rt1: "(Th th', Th th1) \<in> tRAG s" by (unfold tRAG_alt_def, auto)
+        from rp have "rpath (RAG s) x2 xs2 (Th th)"
+           by  (elim rpath_ConsE, simp)
+        from this[unfolded eq_x2] have rp': "rpath (RAG s) (Th th1) xs2 (Th th)" .
+        show ?thesis
+        proof(cases "xs2 = []")
+          case True
+          from rpath_nilE[OF rp'[unfolded this]]
+          have "th1 = th" by auto
+          from rt1[unfolded this] show ?thesis by auto
+        next
+          case False
+          from 1(1)[rule_format, OF _ rp' this, unfolded Cons1 Cons]
+          have "(Th th1, Th th) \<in> (tRAG s)\<^sup>+" by simp
+          with rt1 show ?thesis by auto
+        qed
+      qed
+    qed
+    hence "th' \<in> ?L" by auto
+  } ultimately show ?thesis by blast
+qed
+
+lemma tRAG_trancl_eq_Th:
+   "{Th th' | th'. (Th th', Th th)  \<in> (tRAG s)^+} = 
+    {Th th' | th'. (Th th', Th th)  \<in> (RAG s)^+}"
+    using tRAG_trancl_eq by auto
+
+lemma dependants_alt_def:
+  "dependants s th = {th'. (Th th', Th th) \<in> (tRAG s)^+}"
+  by (metis eq_RAG s_dependants_def tRAG_trancl_eq)
+
+lemma dependants_alt_def1:
+  "dependants (s::state) th = {th'. (Th th', Th th) \<in> (RAG s)^+}"
+  using dependants_alt_def tRAG_trancl_eq by auto
+
+context valid_trace
+begin
+lemma count_eq_RAG_plus:
+  assumes "cntP s th = cntV s th"
+  shows "{th'. (Th th', Th th) \<in> (RAG s)^+} = {}"
+proof(rule ccontr)
+    assume otherwise: "{th'. (Th th', Th th) \<in> (RAG s)\<^sup>+} \<noteq> {}"
+    then obtain th' where "(Th th', Th th) \<in> (RAG s)^+" by auto
+    from tranclD2[OF this]
+    obtain z where "z \<in> children (RAG s) (Th th)" 
+      by (auto simp:children_def)
+    with eq_pv_children[OF assms]
+    show False by simp
+qed
+
+lemma eq_pv_dependants:
+  assumes eq_pv: "cntP s th = cntV s th"
+  shows "dependants s th = {}"
+proof -
+  from count_eq_RAG_plus[OF assms, folded dependants_alt_def1]
+  show ?thesis .
+qed
+
+end
+
+lemma eq_dependants: "dependants (wq s) = dependants s"
+  by (simp add: s_dependants_abv wq_def)
+
+context valid_trace
+begin
+
+lemma count_eq_tRAG_plus:
+  assumes "cntP s th = cntV s th"
+  shows "{th'. (Th th', Th th) \<in> (tRAG s)^+} = {}"
+  using assms eq_pv_dependants dependants_alt_def eq_dependants by auto 
+
+lemma count_eq_RAG_plus_Th:
+  assumes "cntP s th = cntV s th"
+  shows "{Th th' | th'. (Th th', Th th) \<in> (RAG s)^+} = {}"
+  using count_eq_RAG_plus[OF assms] by auto
+
+lemma count_eq_tRAG_plus_Th:
+  assumes "cntP s th = cntV s th"
+  shows "{Th th' | th'. (Th th', Th th) \<in> (tRAG s)^+} = {}"
+   using count_eq_tRAG_plus[OF assms] by auto
+end
+
+lemma inj_the_preced: 
+  "inj_on (the_preced s) (threads s)"
+  by (metis inj_onI preced_unique the_preced_def)
+
+lemma tRAG_Field:
+  "Field (tRAG s) \<subseteq> Field (RAG s)"
+  by (unfold tRAG_alt_def Field_def, auto)
+
+lemma tRAG_ancestorsE:
+  assumes "x \<in> ancestors (tRAG s) u"
+  obtains th where "x = Th th"
+proof -
+  from assms have "(u, x) \<in> (tRAG s)^+" 
+      by (unfold ancestors_def, auto)
+  from tranclE[OF this] obtain c where "(c, x) \<in> tRAG s" by auto
+  then obtain th where "x = Th th"
+    by (unfold tRAG_alt_def, auto)
+  from that[OF this] show ?thesis .
+qed
+
+lemma tRAG_mono:
+  assumes "RAG s' \<subseteq> RAG s"
+  shows "tRAG s' \<subseteq> tRAG s"
+  using assms 
+  by (unfold tRAG_alt_def, auto)
+
+lemma holding_next_thI:
+  assumes "holding s th cs"
+  and "length (wq s cs) > 1"
+  obtains th' where "next_th s th cs th'"
+proof -
+  from assms(1)[folded holding_eq, unfolded cs_holding_def]
+  have " th \<in> set (wq s cs) \<and> th = hd (wq s cs)" 
+    by (unfold s_holding_def, fold wq_def, auto)
+  then obtain rest where h1: "wq s cs = th#rest" 
+    by (cases "wq s cs", auto)
+  with assms(2) have h2: "rest \<noteq> []" by auto
+  let ?th' = "hd (SOME q. distinct q \<and> set q = set rest)"
+  have "next_th s th cs ?th'" using  h1(1) h2 
+    by (unfold next_th_def, auto)
+  from that[OF this] show ?thesis .
+qed
+
+lemma RAG_tRAG_transfer:
+  assumes "vt s'"
+  assumes "RAG s = RAG s' \<union> {(Th th, Cs cs)}"
+  and "(Cs cs, Th th'') \<in> RAG s'"
+  shows "tRAG s = tRAG s' \<union> {(Th th, Th th'')}" (is "?L = ?R")
+proof -
+  interpret vt_s': valid_trace "s'" using assms(1)
+    by (unfold_locales, simp)
+  { fix n1 n2
+    assume "(n1, n2) \<in> ?L"
+    from this[unfolded tRAG_alt_def]
+    obtain th1 th2 cs' where 
+      h: "n1 = Th th1" "n2 = Th th2" 
+         "(Th th1, Cs cs') \<in> RAG s"
+         "(Cs cs', Th th2) \<in> RAG s" by auto
+    from h(4) and assms(2) have cs_in: "(Cs cs', Th th2) \<in> RAG s'" by auto
+    from h(3) and assms(2) 
+    have "(Th th1, Cs cs') = (Th th, Cs cs) \<or> 
+          (Th th1, Cs cs') \<in> RAG s'" by auto
+    hence "(n1, n2) \<in> ?R"
+    proof
+      assume h1: "(Th th1, Cs cs') = (Th th, Cs cs)"
+      hence eq_th1: "th1 = th" by simp
+      moreover have "th2 = th''"
+      proof -
+        from h1 have "cs' = cs" by simp
+        from assms(3) cs_in[unfolded this]
+        show ?thesis using vt_s'.unique_RAG by auto 
+      qed
+      ultimately show ?thesis using h(1,2) by auto
+    next
+      assume "(Th th1, Cs cs') \<in> RAG s'"
+      with cs_in have "(Th th1, Th th2) \<in> tRAG s'"
+        by (unfold tRAG_alt_def, auto)
+      from this[folded h(1, 2)] show ?thesis by auto
+    qed
+  } moreover {
+    fix n1 n2
+    assume "(n1, n2) \<in> ?R"
+    hence "(n1, n2) \<in>tRAG s' \<or> (n1, n2) = (Th th, Th th'')" by auto
+    hence "(n1, n2) \<in> ?L" 
+    proof
+      assume "(n1, n2) \<in> tRAG s'"
+      moreover have "... \<subseteq> ?L"
+      proof(rule tRAG_mono)
+        show "RAG s' \<subseteq> RAG s" by (unfold assms(2), auto)
+      qed
+      ultimately show ?thesis by auto
+    next
+      assume eq_n: "(n1, n2) = (Th th, Th th'')"
+      from assms(2, 3) have "(Cs cs, Th th'') \<in> RAG s" by auto
+      moreover have "(Th th, Cs cs) \<in> RAG s" using assms(2) by auto
+      ultimately show ?thesis 
+        by (unfold eq_n tRAG_alt_def, auto)
+    qed
+  } ultimately show ?thesis by auto
+qed
+
+context valid_trace
+begin
+
+lemmas RAG_tRAG_transfer = RAG_tRAG_transfer[OF vt]
+
+lemma tRAG_subtree_eq: 
+   "(subtree (tRAG s) (Th th)) = {Th th' | th'. Th th'  \<in> (subtree (RAG s) (Th th))}"
+   (is "?L = ?R")
+proof -
+  { fix n 
+    assume h: "n \<in> ?L"
+    hence "n \<in> ?R"
+    by (smt mem_Collect_eq subsetCE subtree_def subtree_nodeE tRAG_subtree_RAG) 
+  } moreover {
+    fix n
+    assume "n \<in> ?R"
+    then obtain th' where h: "n = Th th'" "(Th th', Th th) \<in> (RAG s)^*"
+      by (auto simp:subtree_def)
+    from rtranclD[OF this(2)]
+    have "n \<in> ?L"
+    proof
+      assume "Th th' \<noteq> Th th \<and> (Th th', Th th) \<in> (RAG s)\<^sup>+"
+      with h have "n \<in> {Th th' | th'. (Th th', Th th)  \<in> (RAG s)^+}" by auto
+      thus ?thesis using subtree_def tRAG_trancl_eq by fastforce
+    qed (insert h, auto simp:subtree_def)
+  } ultimately show ?thesis by auto
+qed
+
+lemma threads_set_eq: 
+   "the_thread ` (subtree (tRAG s) (Th th)) = 
+                  {th'. Th th' \<in> (subtree (RAG s) (Th th))}" (is "?L = ?R")
+   by (auto intro:rev_image_eqI simp:tRAG_subtree_eq)
+
+lemma cp_alt_def1: 
+  "cp s th = Max ((the_preced s o the_thread) ` (subtree (tRAG s) (Th th)))"
+proof -
+  have "(the_preced s ` the_thread ` subtree (tRAG s) (Th th)) =
+       ((the_preced s \<circ> the_thread) ` subtree (tRAG s) (Th th))"
+       by auto
+  thus ?thesis by (unfold cp_alt_def, fold threads_set_eq, auto)
+qed
+
+lemma cp_gen_def_cond: 
+  assumes "x = Th th"
+  shows "cp s th = cp_gen s (Th th)"
+by (unfold cp_alt_def1 cp_gen_def, simp)
+
+lemma cp_gen_over_set:
+  assumes "\<forall> x \<in> A. \<exists> th. x = Th th"
+  shows "cp_gen s ` A = (cp s \<circ> the_thread) ` A"
+proof(rule f_image_eq)
+  fix a
+  assume "a \<in> A"
+  from assms[rule_format, OF this]
+  obtain th where eq_a: "a = Th th" by auto
+  show "cp_gen s a = (cp s \<circ> the_thread) a"
+    by  (unfold eq_a, simp, unfold cp_gen_def_cond[OF refl[of "Th th"]], simp)
+qed
+
+lemma subtree_tRAG_thread:
+  assumes "th \<in> threads s"
+  shows "subtree (tRAG s) (Th th) \<subseteq> Th ` threads s" (is "?L \<subseteq> ?R")
+proof -
+  have "?L = {Th th' |th'. Th th' \<in> subtree (RAG s) (Th th)}"
+    by (unfold tRAG_subtree_eq, simp)
+  also have "... \<subseteq> ?R"
+  proof
+    fix x
+    assume "x \<in> {Th th' |th'. Th th' \<in> subtree (RAG s) (Th th)}"
+    then obtain th' where h: "x = Th th'" "Th th' \<in> subtree (RAG s) (Th th)" by auto
+    from this(2)
+    show "x \<in> ?R"
+    proof(cases rule:subtreeE)
+      case 1
+      thus ?thesis by (simp add: assms h(1)) 
+    next
+      case 2
+      thus ?thesis by (metis ancestors_Field dm_RAG_threads h(1) image_eqI) 
+    qed
+  qed
+  finally show ?thesis .
+qed
+
+lemma readys_root:
+  assumes "th \<in> readys s"
+  shows "root (RAG s) (Th th)"
+proof -
+  { fix x
+    assume "x \<in> ancestors (RAG s) (Th th)"
+    hence h: "(Th th, x) \<in> (RAG s)^+" by (auto simp:ancestors_def)
+    from tranclD[OF this]
+    obtain z where "(Th th, z) \<in> RAG s" by auto
+    with assms(1) have False
+         apply (case_tac z, auto simp:readys_def s_RAG_def s_waiting_def cs_waiting_def)
+         by (fold wq_def, blast)
+  } thus ?thesis by (unfold root_def, auto)
+qed
+
+lemma readys_in_no_subtree:
+  assumes "th \<in> readys s"
+  and "th' \<noteq> th"
+  shows "Th th \<notin> subtree (RAG s) (Th th')" 
+proof
+   assume "Th th \<in> subtree (RAG s) (Th th')"
+   thus False
+   proof(cases rule:subtreeE)
+      case 1
+      with assms show ?thesis by auto
+   next
+      case 2
+      with readys_root[OF assms(1)]
+      show ?thesis by (auto simp:root_def)
+   qed
+qed
+
+lemma not_in_thread_isolated:
+  assumes "th \<notin> threads s"
+  shows "(Th th) \<notin> Field (RAG s)"
+proof
+  assume "(Th th) \<in> Field (RAG s)"
+  with dm_RAG_threads and rg_RAG_threads assms
+  show False by (unfold Field_def, blast)
+qed
+
+end
+
+definition detached :: "state \<Rightarrow> thread \<Rightarrow> bool"
+  where "detached s th \<equiv> (\<not>(\<exists> cs. holding s th cs)) \<and> (\<not>(\<exists>cs. waiting s th cs))"
+
+
+lemma detached_test:
+  shows "detached s th = (Th th \<notin> Field (RAG s))"
+apply(simp add: detached_def Field_def)
+apply(simp add: s_RAG_def)
+apply(simp add: s_holding_abv s_waiting_abv)
+apply(simp add: Domain_iff Range_iff)
+apply(simp add: wq_def)
+apply(auto)
+done
+
+context valid_trace
+begin
+
+lemma detached_intro:
+  assumes eq_pv: "cntP s th = cntV s th"
+  shows "detached s th"
+proof -
+  from eq_pv cnp_cnv_cncs
+  have "th \<in> readys s \<or> th \<notin> threads s" by (auto simp:pvD_def)
+  thus ?thesis
+  proof
+    assume "th \<notin> threads s"
+    with rg_RAG_threads dm_RAG_threads
+    show ?thesis
+      by (auto simp add: detached_def s_RAG_def s_waiting_abv 
+              s_holding_abv wq_def Domain_iff Range_iff)
+  next
+    assume "th \<in> readys s"
+    moreover have "Th th \<notin> Range (RAG s)"
+    proof -
+      from eq_pv_children[OF assms]
+      have "children (RAG s) (Th th) = {}" .
+      thus ?thesis
+      by (unfold children_def, auto)
+    qed
+    ultimately show ?thesis
+      by (auto simp add: detached_def s_RAG_def s_waiting_abv 
+              s_holding_abv wq_def readys_def)
+  qed
+qed
+
+lemma detached_elim:
+  assumes dtc: "detached s th"
+  shows "cntP s th = cntV s th"
+proof -
+  have cncs_z: "cntCS s th = 0"
+  proof -
+    from dtc have "holdents s th = {}"
+      unfolding detached_def holdents_test s_RAG_def
+      by (simp add: s_waiting_abv wq_def s_holding_abv Domain_iff Range_iff)
+    thus ?thesis by (auto simp:cntCS_def)
+  qed
+  show ?thesis
+  proof(cases "th \<in> threads s")
+    case True
+    with dtc 
+    have "th \<in> readys s"
+      by (unfold readys_def detached_def Field_def Domain_def Range_def, 
+           auto simp:waiting_eq s_RAG_def)
+    with cncs_z  show ?thesis using cnp_cnv_cncs by (simp add:pvD_def)
+  next
+    case False
+    with cncs_z and cnp_cnv_cncs show ?thesis by (simp add:pvD_def)
+  qed
+qed
+
+lemma detached_eq:
+  shows "(detached s th) = (cntP s th = cntV s th)"
+  by (insert vt, auto intro:detached_intro detached_elim)
+
+lemma tRAG_nodeE:
+  assumes "(n1, n2) \<in> tRAG s"
+  obtains th1 th2 where "n1 = Th th1" "n2 = Th th2"
+  using assms
+  by (auto simp: tRAG_def wRAG_def hRAG_def tRAG_def)
+
+lemma subtree_nodeE:
+  assumes "n \<in> subtree (tRAG s) (Th th)"
+  obtains th1 where "n = Th th1"
+proof -
+  show ?thesis
+  proof(rule subtreeE[OF assms])
+    assume "n = Th th"
+    from that[OF this] show ?thesis .
+  next
+    assume "Th th \<in> ancestors (tRAG s) n"
+    hence "(n, Th th) \<in> (tRAG s)^+" by (auto simp:ancestors_def)
+    hence "\<exists> th1. n = Th th1"
+    proof(induct)
+      case (base y)
+      from tRAG_nodeE[OF this] show ?case by metis
+    next
+      case (step y z)
+      thus ?case by auto
+    qed
+    with that show ?thesis by auto
+  qed
+qed
+
+lemma tRAG_star_RAG: "(tRAG s)^* \<subseteq> (RAG s)^*"
+proof -
+  have "(wRAG s O hRAG s)^* \<subseteq> (RAG s O RAG s)^*" 
+    by (rule rtrancl_mono, auto simp:RAG_split)
+  also have "... \<subseteq> ((RAG s)^*)^*"
+    by (rule rtrancl_mono, auto)
+  also have "... = (RAG s)^*" by simp
+  finally show ?thesis by (unfold tRAG_def, simp)
+qed
+
+lemma tRAG_subtree_RAG: "subtree (tRAG s) x \<subseteq> subtree (RAG s) x"
+proof -
+  { fix a
+    assume "a \<in> subtree (tRAG s) x"
+    hence "(a, x) \<in> (tRAG s)^*" by (auto simp:subtree_def)
+    with tRAG_star_RAG
+    have "(a, x) \<in> (RAG s)^*" by auto
+    hence "a \<in> subtree (RAG s) x" by (auto simp:subtree_def)
+  } thus ?thesis by auto
+qed
+
+lemma tRAG_trancl_eq:
+   "{th'. (Th th', Th th)  \<in> (tRAG s)^+} = 
+    {th'. (Th th', Th th)  \<in> (RAG s)^+}"
+   (is "?L = ?R")
+proof -
+  { fix th'
+    assume "th' \<in> ?L"
+    hence "(Th th', Th th) \<in> (tRAG s)^+" by auto
+    from tranclD[OF this]
+    obtain z where h: "(Th th', z) \<in> tRAG s" "(z, Th th) \<in> (tRAG s)\<^sup>*" by auto
+    from tRAG_subtree_RAG and this(2)
+    have "(z, Th th) \<in> (RAG s)^*" by (meson subsetCE tRAG_star_RAG) 
+    moreover from h(1) have "(Th th', z) \<in> (RAG s)^+" using tRAG_alt_def by auto 
+    ultimately have "th' \<in> ?R"  by auto 
+  } moreover 
+  { fix th'
+    assume "th' \<in> ?R"
+    hence "(Th th', Th th) \<in> (RAG s)^+" by (auto)
+    from plus_rpath[OF this]
+    obtain xs where rp: "rpath (RAG s) (Th th') xs (Th th)" "xs \<noteq> []" by auto
+    hence "(Th th', Th th) \<in> (tRAG s)^+"
+    proof(induct xs arbitrary:th' th rule:length_induct)
+      case (1 xs th' th)
+      then obtain x1 xs1 where Cons1: "xs = x1#xs1" by (cases xs, auto)
+      show ?case
+      proof(cases "xs1")
+        case Nil
+        from 1(2)[unfolded Cons1 Nil]
+        have rp: "rpath (RAG s) (Th th') [x1] (Th th)" .
+        hence "(Th th', x1) \<in> (RAG s)" by (cases, auto)
+        then obtain cs where "x1 = Cs cs" 
+              by (unfold s_RAG_def, auto)
+        from rpath_nnl_lastE[OF rp[unfolded this]]
+        show ?thesis by auto
+      next
+        case (Cons x2 xs2)
+        from 1(2)[unfolded Cons1[unfolded this]]
+        have rp: "rpath (RAG s) (Th th') (x1 # x2 # xs2) (Th th)" .
+        from rpath_edges_on[OF this]
+        have eds: "edges_on (Th th' # x1 # x2 # xs2) \<subseteq> RAG s" .
+        have "(Th th', x1) \<in> edges_on (Th th' # x1 # x2 # xs2)"
+            by (simp add: edges_on_unfold)
+        with eds have rg1: "(Th th', x1) \<in> RAG s" by auto
+        then obtain cs1 where eq_x1: "x1 = Cs cs1" by (unfold s_RAG_def, auto)
+        have "(x1, x2) \<in> edges_on (Th th' # x1 # x2 # xs2)"
+            by (simp add: edges_on_unfold)
+        from this eds
+        have rg2: "(x1, x2) \<in> RAG s" by auto
+        from this[unfolded eq_x1] 
+        obtain th1 where eq_x2: "x2 = Th th1" by (unfold s_RAG_def, auto)
+        from rg1[unfolded eq_x1] rg2[unfolded eq_x1 eq_x2]
+        have rt1: "(Th th', Th th1) \<in> tRAG s" by (unfold tRAG_alt_def, auto)
+        from rp have "rpath (RAG s) x2 xs2 (Th th)"
+           by  (elim rpath_ConsE, simp)
+        from this[unfolded eq_x2] have rp': "rpath (RAG s) (Th th1) xs2 (Th th)" .
+        show ?thesis
+        proof(cases "xs2 = []")
+          case True
+          from rpath_nilE[OF rp'[unfolded this]]
+          have "th1 = th" by auto
+          from rt1[unfolded this] show ?thesis by auto
+        next
+          case False
+          from 1(1)[rule_format, OF _ rp' this, unfolded Cons1 Cons]
+          have "(Th th1, Th th) \<in> (tRAG s)\<^sup>+" by simp
+          with rt1 show ?thesis by auto
+        qed
+      qed
+    qed
+    hence "th' \<in> ?L" by auto
+  } ultimately show ?thesis by blast
+qed
+
+lemma tRAG_trancl_eq_Th:
+   "{Th th' | th'. (Th th', Th th)  \<in> (tRAG s)^+} = 
+    {Th th' | th'. (Th th', Th th)  \<in> (RAG s)^+}"
+    using tRAG_trancl_eq by auto
+
+lemma dependants_alt_def:
+  "dependants s th = {th'. (Th th', Th th) \<in> (tRAG s)^+}"
+  by (metis eq_RAG s_dependants_def tRAG_trancl_eq)
+
+(* ddd *)
+lemma cp_gen_rec:
+  assumes "x = Th th"
+  shows "cp_gen s x = Max ({the_preced s th} \<union> (cp_gen s) ` children (tRAG s) x)"
+proof(cases "children (tRAG s) x = {}")
+  case True
+  show ?thesis
+    by (unfold True cp_gen_def subtree_children, simp add:assms)
+next
+  case False
+  hence [simp]: "children (tRAG s) x \<noteq> {}" by auto
+  note fsbttRAGs.finite_subtree[simp]
+  have [simp]: "finite (children (tRAG s) x)"
+     by (intro rev_finite_subset[OF fsbttRAGs.finite_subtree], 
+            rule children_subtree)
+  { fix r x
+    have "subtree r x \<noteq> {}" by (auto simp:subtree_def)
+  } note this[simp]
+  have [simp]: "\<exists>x\<in>children (tRAG s) x. subtree (tRAG s) x \<noteq> {}"
+  proof -
+    from False obtain q where "q \<in> children (tRAG s) x" by blast
+    moreover have "subtree (tRAG s) q \<noteq> {}" by simp
+    ultimately show ?thesis by blast
+  qed
+  have h: "Max ((the_preced s \<circ> the_thread) `
+                ({x} \<union> \<Union>(subtree (tRAG s) ` children (tRAG s) x))) =
+        Max ({the_preced s th} \<union> cp_gen s ` children (tRAG s) x)"
+                     (is "?L = ?R")
+  proof -
+    let "Max (?f ` (?A \<union> \<Union> (?g ` ?B)))" = ?L
+    let "Max (_ \<union> (?h ` ?B))" = ?R
+    let ?L1 = "?f ` \<Union>(?g ` ?B)"
+    have eq_Max_L1: "Max ?L1 = Max (?h ` ?B)"
+    proof -
+      have "?L1 = ?f ` (\<Union> x \<in> ?B.(?g x))" by simp
+      also have "... =  (\<Union> x \<in> ?B. ?f ` (?g x))" by auto
+      finally have "Max ?L1 = Max ..." by simp
+      also have "... = Max (Max ` (\<lambda>x. ?f ` subtree (tRAG s) x) ` ?B)"
+        by (subst Max_UNION, simp+)
+      also have "... = Max (cp_gen s ` children (tRAG s) x)"
+          by (unfold image_comp cp_gen_alt_def, simp)
+      finally show ?thesis .
+    qed
+    show ?thesis
+    proof -
+      have "?L = Max (?f ` ?A \<union> ?L1)" by simp
+      also have "... = max (the_preced s (the_thread x)) (Max ?L1)"
+            by (subst Max_Un, simp+)
+      also have "... = max (?f x) (Max (?h ` ?B))"
+        by (unfold eq_Max_L1, simp)
+      also have "... =?R"
+        by (rule max_Max_eq, (simp)+, unfold assms, simp)
+      finally show ?thesis .
+    qed
+  qed  thus ?thesis 
+          by (fold h subtree_children, unfold cp_gen_def, simp) 
+qed
+
+lemma cp_rec:
+  "cp s th = Max ({the_preced s th} \<union> 
+                     (cp s o the_thread) ` children (tRAG s) (Th th))"
+proof -
+  have "Th th = Th th" by simp
+  note h =  cp_gen_def_cond[OF this] cp_gen_rec[OF this]
+  show ?thesis 
+  proof -
+    have "cp_gen s ` children (tRAG s) (Th th) = 
+                (cp s \<circ> the_thread) ` children (tRAG s) (Th th)"
+    proof(rule cp_gen_over_set)
+      show " \<forall>x\<in>children (tRAG s) (Th th). \<exists>th. x = Th th"
+        by (unfold tRAG_alt_def, auto simp:children_def)
+    qed
+    thus ?thesis by (subst (1) h(1), unfold h(2), simp)
+  qed
+qed
+
+lemma next_th_holding:
+  assumes nxt: "next_th s th cs th'"
+  shows "holding (wq s) th cs"
+proof -
+  from nxt[unfolded next_th_def]
+  obtain rest where h: "wq s cs = th # rest"
+                       "rest \<noteq> []" 
+                       "th' = hd (SOME q. distinct q \<and> set q = set rest)" by auto
+  thus ?thesis
+    by (unfold cs_holding_def, auto)
+qed
+
+lemma next_th_waiting:
+  assumes nxt: "next_th s th cs th'"
+  shows "waiting (wq s) th' cs"
+proof -
+  from nxt[unfolded next_th_def]
+  obtain rest where h: "wq s cs = th # rest"
+                       "rest \<noteq> []" 
+                       "th' = hd (SOME q. distinct q \<and> set q = set rest)" by auto
+  from wq_distinct[of cs, unfolded h]
+  have dst: "distinct (th # rest)" .
+  have in_rest: "th' \<in> set rest"
+  proof(unfold h, rule someI2)
+    show "distinct rest \<and> set rest = set rest" using dst by auto
+  next
+    fix x assume "distinct x \<and> set x = set rest"
+    with h(2)
+    show "hd x \<in> set (rest)" by (cases x, auto)
+  qed
+  hence "th' \<in> set (wq s cs)" by (unfold h(1), auto)
+  moreover have "th' \<noteq> hd (wq s cs)"
+    by (unfold h(1), insert in_rest dst, auto)
+  ultimately show ?thesis by (auto simp:cs_waiting_def)
+qed
+
+lemma next_th_RAG:
+  assumes nxt: "next_th (s::event list) th cs th'"
+  shows "{(Cs cs, Th th), (Th th', Cs cs)} \<subseteq> RAG s"
+  using vt assms next_th_holding next_th_waiting
+  by (unfold s_RAG_def, simp)
+
+end
+
+end
+




