Implementation.thy
changeset 97 c7ba70dc49bd
parent 95 8d2cc27f45f3
parent 93 524bd3caa6b6
child 104 43482ab31341
--- a/Implementation.thy	Thu Jan 28 14:57:36 2016 +0000
+++ b/Implementation.thy	Fri Jan 29 17:06:02 2016 +0000
@@ -37,30 +37,7 @@
 
 section {* The @{term Set} operation *}
 
-text {* (* ddd *)
-  The following locale @{text "step_set_cps"} investigates the recalculation 
-  after the @{text "Set"} operation.
-*}
-locale step_set_cps =
-  fixes s' th prio s 
-  -- {* @{text "s'"} is the system state before the operation *}
-  -- {* @{text "s"} is the system state after the operation *}
-  defines s_def : "s \<equiv> (Set th prio#s')" 
-  -- {* @{text "s"} is assumed to be a legitimate state, from which
-         the legitimacy of @{text "s"} can be derived. *}
-  assumes vt_s: "vt s"
-
-sublocale step_set_cps < vat_s : valid_trace "s"
-proof
-  from vt_s show "vt s" .
-qed
-
-sublocale step_set_cps < vat_s' : valid_trace "s'"
-proof
-  from step_back_vt[OF vt_s[unfolded s_def]] show "vt s'" .
-qed
-
-context step_set_cps 
+context valid_trace_set
 begin
 
 text {* (* ddd *)
@@ -69,26 +46,21 @@
   of the operation (or event).
 *}
 
+
 lemma eq_preced:
   assumes "th' \<noteq> th"
-  shows "preced th' s = preced th' s'"
+  shows "preced th' (e#s) = preced th' s"
 proof -
   from assms show ?thesis 
-    by (unfold s_def, auto simp:preced_def)
+    by (unfold is_set, auto simp:preced_def)
 qed
 
 lemma eq_the_preced: 
   assumes "th' \<noteq> th"
-  shows "the_preced s th' = the_preced s' th'"
+  shows "the_preced (e#s) th' = the_preced s th'"
   using assms
   by (unfold the_preced_def, intro eq_preced, simp)
 
-text {*
-  The following lemma assures that the resetting of priority does not change the RAG. 
-*}
-
-lemma eq_dep: "RAG s = RAG s'"
-  by (unfold s_def RAG_set_unchanged, auto)
 
 text {* (* ddd *)
   Th following lemma @{text "eq_cp_pre"} says that the priority change of @{text "th"}
@@ -99,18 +71,18 @@
 *}
 
 lemma eq_cp_pre:
-  assumes nd: "Th th \<notin> subtree (RAG s') (Th th')"
-  shows "cp s th' = cp s' th'"
+  assumes nd: "Th th \<notin> subtree (RAG s) (Th th')"
+  shows "cp (e#s) th' = cp s th'"
 proof -
   -- {* After unfolding using the alternative definition, elements 
         affecting the @{term "cp"}-value of threads become explicit. 
         We only need to prove the following: *}
-  have "Max (the_preced s ` {th'a. Th th'a \<in> subtree (RAG s) (Th th')}) =
-        Max (the_preced s' ` {th'a. Th th'a \<in> subtree (RAG s') (Th th')})"
+  have "Max (the_preced (e#s) ` {th'a. Th th'a \<in> subtree (RAG (e#s)) (Th th')}) =
+        Max (the_preced s ` {th'a. Th th'a \<in> subtree (RAG s) (Th th')})"
         (is "Max (?f ` ?S1) = Max (?g ` ?S2)")
   proof -
     -- {* The base sets are equal. *}
-    have "?S1 = ?S2" using eq_dep by simp
+    have "?S1 = ?S2" using RAG_unchanged by simp
     -- {* The function values on the base set are equal as well. *}
     moreover have "\<forall> e \<in> ?S2. ?f e = ?g e"
     proof
@@ -118,7 +90,7 @@
       assume "th1 \<in> ?S2"
       with nd have "th1 \<noteq> th" by (auto)
       from eq_the_preced[OF this]
-      show "the_preced s th1 = the_preced s' th1" .
+      show "the_preced (e#s) th1 = the_preced s th1" .
     qed
     -- {* Therefore, the image of the functions are equal. *}
     ultimately have "(?f ` ?S1) = (?g ` ?S2)" by (auto intro!:f_image_eq)
@@ -133,16 +105,9 @@
 *}
 lemma th_in_no_subtree:
   assumes "th' \<noteq> th"
-  shows "Th th \<notin> subtree (RAG s') (Th th')"
+  shows "Th th \<notin> subtree (RAG s) (Th th')"
 proof -
-  have "th \<in> readys s'"
-  proof -
-    from step_back_step [OF vt_s[unfolded s_def]]
-    have "step s' (Set th prio)" .
-    hence "th \<in> runing s'" by (cases, simp)
-    thus ?thesis by (simp add:readys_def runing_def)
-  qed
-  from vat_s'.readys_in_no_subtree[OF this assms(1)]
+  from readys_in_no_subtree[OF th_ready_s assms(1)]
   show ?thesis by blast
 qed
 
@@ -153,7 +118,7 @@
 *}
 lemma eq_cp:
   assumes "th' \<noteq> th"
-  shows "cp s th' = cp s' th'"
+  shows "cp (e#s) th' = cp s th'"
   by (rule eq_cp_pre[OF th_in_no_subtree[OF assms]])
 
 end
@@ -164,73 +129,33 @@
   The following @{text "step_v_cps"} is the locale for @{text "V"}-operation.
 *}
 
-locale step_v_cps =
-  -- {* @{text "th"} is the initiating thread *}
-  -- {* @{text "cs"} is the critical resource release by the @{text "V"}-operation *}
-  fixes s' th cs s    -- {* @{text "s'"} is the state before operation*}
-  defines s_def : "s \<equiv> (V th cs#s')" -- {* @{text "s"} is the state after operation*}
-  -- {* @{text "s"} is assumed to be valid, which implies the validity of @{text "s'"} *}
-  assumes vt_s: "vt s"
 
-sublocale step_v_cps < vat_s : valid_trace "s"
-proof
-  from vt_s show "vt s" .
-qed
-
-sublocale step_v_cps < vat_s' : valid_trace "s'"
-proof
-  from step_back_vt[OF vt_s[unfolded s_def]] show "vt s'" .
-qed
-
-context step_v_cps
+context valid_trace_v
 begin
 
-lemma ready_th_s': "th \<in> readys s'"
-  using step_back_step[OF vt_s[unfolded s_def]]
-  by (cases, simp add:runing_def)
-
-lemma ancestors_th: "ancestors (RAG s') (Th th) = {}"
+lemma ancestors_th: "ancestors (RAG s) (Th th) = {}"
 proof -
-  from vat_s'.readys_root[OF ready_th_s']
+  from readys_root[OF th_ready_s]
   show ?thesis
   by (unfold root_def, simp)
 qed
 
-lemma holding_th: "holding s' th cs"
+lemma edge_of_th:
+    "(Cs cs, Th th) \<in> RAG s" 
 proof -
-  from vt_s[unfolded s_def]
-  have " PIP s' (V th cs)" by (cases, simp)
-  thus ?thesis by (cases, auto)
-qed
-
-lemma edge_of_th:
-    "(Cs cs, Th th) \<in> RAG s'" 
-proof -
- from holding_th
+ from holding_th_cs_s
  show ?thesis 
     by (unfold s_RAG_def holding_eq, auto)
 qed
 
 lemma ancestors_cs: 
-  "ancestors (RAG s') (Cs cs) = {Th th}"
+  "ancestors (RAG s) (Cs cs) = {Th th}"
 proof -
-  have "ancestors (RAG s') (Cs cs) = ancestors (RAG s') (Th th)  \<union>  {Th th}"
-  proof(rule vat_s'.rtree_RAG.ancestors_accum)
-    from vt_s[unfolded s_def]
-    have " PIP s' (V th cs)" by (cases, simp)
-    thus "(Cs cs, Th th) \<in> RAG s'" 
-    proof(cases)
-      assume "holding s' th cs"
-      from this[unfolded holding_eq]
-      show ?thesis by (unfold s_RAG_def, auto)
-    qed
-  qed
+  have "ancestors (RAG s) (Cs cs) = ancestors (RAG s) (Th th)  \<union>  {Th th}"
+   by (rule rtree_RAG.ancestors_accum[OF edge_of_th])
   from this[unfolded ancestors_th] show ?thesis by simp
 qed
 
-lemma preced_kept: "the_preced s = the_preced s'"
-  by (auto simp: s_def the_preced_def preced_def)
-
 end
 
 text {*
@@ -238,147 +163,99 @@
   which represents the case when there is another thread @{text "th'"}
   to take over the critical resource released by the initiating thread @{text "th"}.
 *}
-locale step_v_cps_nt = step_v_cps +
-  fixes th'
-  -- {* @{text "th'"} is assumed to take over @{text "cs"} *}
-  assumes nt: "next_th s' th cs th'" 
 
-context step_v_cps_nt
+context valid_trace_v_n
 begin
 
-text {*
-  Lemma @{text "RAG_s"} confirms the change of RAG:
-  two edges removed and one added, as shown by the following diagram.
-*}
-
-(*
-  RAG before the V-operation
-    th1 ----|
-            |
-    th' ----|
-            |----> cs -----|
-    th2 ----|              |
-            |              |
-    th3 ----|              |
-                           |------> th
-    th4 ----|              |
-            |              |
-    th5 ----|              |
-            |----> cs'-----|
-    th6 ----|
-            |
-    th7 ----|
-
- RAG after the V-operation
-    th1 ----|
-            |
-            |----> cs ----> th'
-    th2 ----|              
-            |              
-    th3 ----|              
-                           
-    th4 ----|              
-            |              
-    th5 ----|              
-            |----> cs'----> th
-    th6 ----|
-            |
-    th7 ----|
-*)
-
-lemma sub_RAGs': "{(Cs cs, Th th), (Th th', Cs cs)} \<subseteq> RAG s'"
-                using next_th_RAG[OF nt]  .
+lemma sub_RAGs': 
+  "{(Cs cs, Th th), (Th taker, Cs cs)} \<subseteq> RAG s"
+     using next_th_RAG[OF next_th_taker]  .
 
 lemma ancestors_th': 
-  "ancestors (RAG s') (Th th') = {Th th, Cs cs}" 
+  "ancestors (RAG s) (Th taker) = {Th th, Cs cs}" 
 proof -
-  have "ancestors (RAG s') (Th th') = ancestors (RAG s') (Cs cs) \<union> {Cs cs}"
-  proof(rule  vat_s'.rtree_RAG.ancestors_accum)
-    from sub_RAGs' show "(Th th', Cs cs) \<in> RAG s'" by auto
+  have "ancestors (RAG s) (Th taker) = ancestors (RAG s) (Cs cs) \<union> {Cs cs}"
+  proof(rule  rtree_RAG.ancestors_accum)
+    from sub_RAGs' show "(Th taker, Cs cs) \<in> RAG s" by auto
   qed
   thus ?thesis using ancestors_th ancestors_cs by auto
 qed
 
 lemma RAG_s:
-  "RAG s = (RAG s' - {(Cs cs, Th th), (Th th', Cs cs)}) \<union>
-                                         {(Cs cs, Th th')}"
-proof -
-  from step_RAG_v[OF vt_s[unfolded s_def], folded s_def]
-    and nt show ?thesis  by (auto intro:next_th_unique)
-qed
+  "RAG (e#s) = (RAG s - {(Cs cs, Th th), (Th taker, Cs cs)}) \<union>
+                                         {(Cs cs, Th taker)}"
+ by (unfold RAG_es waiting_set_eq holding_set_eq, auto)
 
 lemma subtree_kept: (* ddd *)
-  assumes "th1 \<notin> {th, th'}"
-  shows "subtree (RAG s) (Th th1) = subtree (RAG s') (Th th1)" (is "_ = ?R")
+  assumes "th1 \<notin> {th, taker}"
+  shows "subtree (RAG (e#s)) (Th th1) = 
+                     subtree (RAG s) (Th th1)" (is "_ = ?R")
 proof -
-  let ?RAG' = "(RAG s' - {(Cs cs, Th th), (Th th', Cs cs)})"
-  let ?RAG'' = "?RAG' \<union> {(Cs cs, Th th')}"
+  let ?RAG' = "(RAG s - {(Cs cs, Th th), (Th taker, Cs cs)})"
+  let ?RAG'' = "?RAG' \<union> {(Cs cs, Th taker)}"
   have "subtree ?RAG' (Th th1) = ?R" 
   proof(rule subset_del_subtree_outside)
-    show "Range {(Cs cs, Th th), (Th th', Cs cs)} \<inter> subtree (RAG s') (Th th1) = {}"
+    show "Range {(Cs cs, Th th), (Th taker, Cs cs)} \<inter> subtree (RAG s) (Th th1) = {}"
     proof -
-      have "(Th th) \<notin> subtree (RAG s') (Th th1)"
+      have "(Th th) \<notin> subtree (RAG s) (Th th1)"
       proof(rule subtree_refute)
-        show "Th th1 \<notin> ancestors (RAG s') (Th th)"
+        show "Th th1 \<notin> ancestors (RAG s) (Th th)"
           by (unfold ancestors_th, simp)
       next
         from assms show "Th th1 \<noteq> Th th" by simp
       qed
-      moreover have "(Cs cs) \<notin>  subtree (RAG s') (Th th1)"
+      moreover have "(Cs cs) \<notin>  subtree (RAG s) (Th th1)"
       proof(rule subtree_refute)
-        show "Th th1 \<notin> ancestors (RAG s') (Cs cs)"
+        show "Th th1 \<notin> ancestors (RAG s) (Cs cs)"
           by (unfold ancestors_cs, insert assms, auto)
       qed simp
-      ultimately have "{Th th, Cs cs} \<inter> subtree (RAG s') (Th th1) = {}" by auto
+      ultimately have "{Th th, Cs cs} \<inter> subtree (RAG s) (Th th1) = {}" by auto
       thus ?thesis by simp
      qed
   qed
   moreover have "subtree ?RAG'' (Th th1) =  subtree ?RAG' (Th th1)"
   proof(rule subtree_insert_next)
-    show "Th th' \<notin> subtree (RAG s' - {(Cs cs, Th th), (Th th', Cs cs)}) (Th th1)"
+    show "Th taker \<notin> subtree (RAG s - {(Cs cs, Th th), (Th taker, Cs cs)}) (Th th1)"
     proof(rule subtree_refute)
-      show "Th th1 \<notin> ancestors (RAG s' - {(Cs cs, Th th), (Th th', Cs cs)}) (Th th')"
+      show "Th th1 \<notin> ancestors (RAG s - {(Cs cs, Th th), (Th taker, Cs cs)}) (Th taker)"
             (is "_ \<notin> ?R")
       proof -
-          have "?R \<subseteq> ancestors (RAG s') (Th th')" by (rule ancestors_mono, auto)
+          have "?R \<subseteq> ancestors (RAG s) (Th taker)" by (rule ancestors_mono, auto)
           moreover have "Th th1 \<notin> ..." using ancestors_th' assms by simp
           ultimately show ?thesis by auto
       qed
     next
-      from assms show "Th th1 \<noteq> Th th'" by simp
+      from assms show "Th th1 \<noteq> Th taker" by simp
     qed
   qed
   ultimately show ?thesis by (unfold RAG_s, simp)
 qed
 
 lemma cp_kept:
-  assumes "th1 \<notin> {th, th'}"
-  shows "cp s th1 = cp s' th1"
-    by (unfold cp_alt_def preced_kept subtree_kept[OF assms], simp)
+  assumes "th1 \<notin> {th, taker}"
+  shows "cp (e#s) th1 = cp s th1"
+    by (unfold cp_alt_def the_preced_es subtree_kept[OF assms], simp)
 
 end
 
-locale step_v_cps_nnt = step_v_cps +
-  assumes nnt: "\<And> th'. (\<not> next_th s' th cs th')"
 
-context step_v_cps_nnt
+context valid_trace_v_e
 begin
 
-lemma RAG_s: "RAG s = RAG s' - {(Cs cs, Th th)}"
-proof -
-  from nnt and  step_RAG_v[OF vt_s[unfolded s_def], folded s_def]
-  show ?thesis by auto
-qed
+find_theorems RAG s e
+
+lemma RAG_s: "RAG (e#s) = RAG s - {(Cs cs, Th th)}"
+  by (unfold RAG_es waiting_set_eq holding_set_eq, simp)
 
 lemma subtree_kept:
   assumes "th1 \<noteq> th"
-  shows "subtree (RAG s) (Th th1) = subtree (RAG s') (Th th1)"
+  shows "subtree (RAG (e#s)) (Th th1) = subtree (RAG s) (Th th1)"
 proof(unfold RAG_s, rule subset_del_subtree_outside)
-  show "Range {(Cs cs, Th th)} \<inter> subtree (RAG s') (Th th1) = {}"
+  show "Range {(Cs cs, Th th)} \<inter> subtree (RAG s) (Th th1) = {}"
   proof -
-    have "(Th th) \<notin> subtree (RAG s') (Th th1)"
+    have "(Th th) \<notin> subtree (RAG s) (Th th1)"
     proof(rule subtree_refute)
-      show "Th th1 \<notin> ancestors (RAG s') (Th th)"
+      show "Th th1 \<notin> ancestors (RAG s) (Th th)"
           by (unfold ancestors_th, simp)
     next
       from assms show "Th th1 \<noteq> Th th" by simp
@@ -389,94 +266,72 @@
 
 lemma cp_kept_1:
   assumes "th1 \<noteq> th"
-  shows "cp s th1 = cp s' th1"
-    by (unfold cp_alt_def preced_kept subtree_kept[OF assms], simp)
+  shows "cp (e#s) th1 = cp s th1"
+    by (unfold cp_alt_def the_preced_es subtree_kept[OF assms], simp)
 
-lemma subtree_cs: "subtree (RAG s') (Cs cs) = {Cs cs}"
+lemma subtree_cs: "subtree (RAG s) (Cs cs) = {Cs cs}"
 proof -
   { fix n
-    have "(Cs cs) \<notin> ancestors (RAG s') n"
+    have "(Cs cs) \<notin> ancestors (RAG s) n"
     proof
-      assume "Cs cs \<in> ancestors (RAG s') n"
-      hence "(n, Cs cs) \<in> (RAG s')^+" by (auto simp:ancestors_def)
-      from tranclE[OF this] obtain nn where h: "(nn, Cs cs) \<in> RAG s'" by auto
+      assume "Cs cs \<in> ancestors (RAG s) n"
+      hence "(n, Cs cs) \<in> (RAG s)^+" by (auto simp:ancestors_def)
+      from tranclE[OF this] obtain nn where h: "(nn, Cs cs) \<in> RAG s" by auto
       then obtain th' where "nn = Th th'"
         by (unfold s_RAG_def, auto)
-      from h[unfolded this] have "(Th th', Cs cs) \<in> RAG s'" .
+      from h[unfolded this] have "(Th th', Cs cs) \<in> RAG s" .
       from this[unfolded s_RAG_def]
-      have "waiting (wq s') th' cs" by auto
+      have "waiting (wq s) th' cs" by auto
       from this[unfolded cs_waiting_def]
-      have "1 < length (wq s' cs)"
-          by (cases "wq s' cs", auto)
-      from holding_next_thI[OF holding_th this]
-      obtain th' where "next_th s' th cs th'" by auto
-      with nnt show False by auto
+      have "1 < length (wq s cs)"
+          by (cases "wq s cs", auto)
+      from holding_next_thI[OF holding_th_cs_s this]
+      obtain th' where "next_th s th cs th'" by auto
+      thus False using no_taker by blast
     qed
   } note h = this
   {  fix n
-     assume "n \<in> subtree (RAG s') (Cs cs)"
+     assume "n \<in> subtree (RAG s) (Cs cs)"
      hence "n = (Cs cs)"
      by (elim subtreeE, insert h, auto)
-  } moreover have "(Cs cs) \<in> subtree (RAG s') (Cs cs)"
+  } moreover have "(Cs cs) \<in> subtree (RAG s) (Cs cs)"
       by (auto simp:subtree_def)
   ultimately show ?thesis by auto 
 qed
 
 lemma subtree_th: 
-  "subtree (RAG s) (Th th) = subtree (RAG s') (Th th) - {Cs cs}"
-proof(unfold RAG_s, fold subtree_cs, rule vat_s'.rtree_RAG.subtree_del_inside)
+  "subtree (RAG (e#s)) (Th th) = subtree (RAG s) (Th th) - {Cs cs}"
+proof(unfold RAG_s, fold subtree_cs, rule rtree_RAG.subtree_del_inside)
   from edge_of_th
-  show "(Cs cs, Th th) \<in> edges_in (RAG s') (Th th)"
+  show "(Cs cs, Th th) \<in> edges_in (RAG s) (Th th)"
     by (unfold edges_in_def, auto simp:subtree_def)
 qed
 
 lemma cp_kept_2: 
-  shows "cp s th = cp s' th" 
- by (unfold cp_alt_def subtree_th preced_kept, auto)
+  shows "cp (e#s) th = cp s th" 
+ by (unfold cp_alt_def subtree_th the_preced_es, auto)
 
 lemma eq_cp:
-  shows "cp s th' = cp s' th'"
+  shows "cp (e#s) th' = cp s th'"
   using cp_kept_1 cp_kept_2
   by (cases "th' = th", auto)
+
 end
 
 
-locale step_P_cps =
-  fixes s' th cs s 
-  defines s_def : "s \<equiv> (P th cs#s')"
-  assumes vt_s: "vt s"
-
-sublocale step_P_cps < vat_s : valid_trace "s"
-proof
-  from vt_s show "vt s" .
-qed
-
 section {* The @{term P} operation *}
 
-sublocale step_P_cps < vat_s' : valid_trace "s'"
-proof
-  from step_back_vt[OF vt_s[unfolded s_def]] show "vt s'" .
-qed
-
-context step_P_cps
+context valid_trace_p
 begin
 
-lemma readys_th: "th \<in> readys s'"
-proof -
-    from step_back_step [OF vt_s[unfolded s_def]]
-    have "PIP s' (P th cs)" .
-    hence "th \<in> runing s'" by (cases, simp)
-    thus ?thesis by (simp add:readys_def runing_def)
-qed
-
-lemma root_th: "root (RAG s') (Th th)"
-  using readys_root[OF readys_th] .
+lemma root_th: "root (RAG s) (Th th)"
+  by (simp add: ready_th_s readys_root)
 
 lemma in_no_others_subtree:
   assumes "th' \<noteq> th"
-  shows "Th th \<notin> subtree (RAG s') (Th th')"
+  shows "Th th \<notin> subtree (RAG s) (Th th')"
 proof
-  assume "Th th \<in> subtree (RAG s') (Th th')"
+  assume "Th th \<in> subtree (RAG s) (Th th')"
   thus False
   proof(cases rule:subtreeE)
     case 1
@@ -487,162 +342,140 @@
   qed
 qed
 
-lemma preced_kept: "the_preced s = the_preced s'"
-  by (auto simp: s_def the_preced_def preced_def)
+lemma preced_kept: "the_preced (e#s) = the_preced s"
+proof
+  fix th'
+  show "the_preced (e # s) th' = the_preced s th'"
+    by (unfold the_preced_def is_p preced_def, simp)
+qed
 
 end
 
-locale step_P_cps_ne =step_P_cps +
-  fixes th'
-  assumes ne: "wq s' cs \<noteq> []"
-  defines th'_def: "th' \<equiv> hd (wq s' cs)"
 
-locale step_P_cps_e =step_P_cps +
-  assumes ee: "wq s' cs = []"
-
-context step_P_cps_e
+context valid_trace_p_h
 begin
 
-lemma RAG_s: "RAG s = RAG s' \<union> {(Cs cs, Th th)}"
-proof -
-  from ee and  step_RAG_p[OF vt_s[unfolded s_def], folded s_def]
-  show ?thesis by auto
-qed
-
 lemma subtree_kept:
   assumes "th' \<noteq> th"
-  shows "subtree (RAG s) (Th th') = subtree (RAG s') (Th th')"
-proof(unfold RAG_s, rule subtree_insert_next)
+  shows "subtree (RAG (e#s)) (Th th') = subtree (RAG s) (Th th')"
+proof(unfold RAG_es, rule subtree_insert_next)
   from in_no_others_subtree[OF assms] 
-  show "Th th \<notin> subtree (RAG s') (Th th')" .
+  show "Th th \<notin> subtree (RAG s) (Th th')" .
 qed
 
 lemma cp_kept: 
   assumes "th' \<noteq> th"
-  shows "cp s th' = cp s' th'"
+  shows "cp (e#s) th' = cp s th'"
 proof -
-  have "(the_preced s ` {th'a. Th th'a \<in> subtree (RAG s) (Th th')}) =
-        (the_preced s' ` {th'a. Th th'a \<in> subtree (RAG s') (Th th')})"
+  have "(the_preced (e#s) ` {th'a. Th th'a \<in> subtree (RAG (e#s)) (Th th')}) =
+        (the_preced s ` {th'a. Th th'a \<in> subtree (RAG s) (Th th')})"
         by (unfold preced_kept subtree_kept[OF assms], simp)
   thus ?thesis by (unfold cp_alt_def, simp)
 qed
 
 end
 
-context step_P_cps_ne 
+context valid_trace_p_w
 begin
 
-lemma RAG_s: "RAG s = RAG s' \<union> {(Th th, Cs cs)}"
-proof -
-  from step_RAG_p[OF vt_s[unfolded s_def]] and ne
-  show ?thesis by (simp add:s_def)
-qed
+interpretation vat_e: valid_trace "e#s"
+  by (unfold_locales, insert vt_e, simp)
 
-lemma cs_held: "(Cs cs, Th th') \<in> RAG s'"
-proof -
-  have "(Cs cs, Th th') \<in> hRAG s'"
-  proof -
-    from ne
-    have " holding s' th' cs"
-      by (unfold th'_def holding_eq cs_holding_def, auto)
-    thus ?thesis 
-      by (unfold hRAG_def, auto)
-  qed
-  thus ?thesis by (unfold RAG_split, auto)
-qed
+lemma cs_held: "(Cs cs, Th holder) \<in> RAG s"
+  using holding_s_holder
+  by (unfold s_RAG_def, fold holding_eq, auto)
 
 lemma tRAG_s: 
-  "tRAG s = tRAG s' \<union> {(Th th, Th th')}"
-  using RAG_tRAG_transfer[OF RAG_s cs_held] .
+  "tRAG (e#s) = tRAG s \<union> {(Th th, Th holder)}"
+  using local.RAG_tRAG_transfer[OF RAG_es cs_held] .
 
 lemma cp_kept:
-  assumes "Th th'' \<notin> ancestors (tRAG s) (Th th)"
-  shows "cp s th'' = cp s' th''"
+  assumes "Th th'' \<notin> ancestors (tRAG (e#s)) (Th th)"
+  shows "cp (e#s) th'' = cp s th''"
 proof -
-  have h: "subtree (tRAG s) (Th th'') = subtree (tRAG s') (Th th'')"
+  have h: "subtree (tRAG (e#s)) (Th th'') = subtree (tRAG s) (Th th'')"
   proof -
-    have "Th th' \<notin> subtree (tRAG s') (Th th'')"
+    have "Th holder \<notin> subtree (tRAG s) (Th th'')"
     proof
-      assume "Th th' \<in> subtree (tRAG s') (Th th'')"
+      assume "Th holder \<in> subtree (tRAG s) (Th th'')"
       thus False
       proof(rule subtreeE)
-         assume "Th th' = Th th''"
+         assume "Th holder = Th th''"
          from assms[unfolded tRAG_s ancestors_def, folded this]
          show ?thesis by auto
       next
-         assume "Th th'' \<in> ancestors (tRAG s') (Th th')"
-         moreover have "... \<subseteq> ancestors (tRAG s) (Th th')"
+         assume "Th th'' \<in> ancestors (tRAG s) (Th holder)"
+         moreover have "... \<subseteq> ancestors (tRAG (e#s)) (Th holder)"
          proof(rule ancestors_mono)
-            show "tRAG s' \<subseteq> tRAG s" by (unfold tRAG_s, auto)
+            show "tRAG s \<subseteq> tRAG (e#s)" by (unfold tRAG_s, auto)
          qed 
-         ultimately have "Th th'' \<in> ancestors (tRAG s) (Th th')" by auto
-         moreover have "Th th' \<in> ancestors (tRAG s) (Th th)"
+         ultimately have "Th th'' \<in> ancestors (tRAG (e#s)) (Th holder)" by auto
+         moreover have "Th holder \<in> ancestors (tRAG (e#s)) (Th th)"
            by (unfold tRAG_s, auto simp:ancestors_def)
-         ultimately have "Th th'' \<in> ancestors (tRAG s) (Th th)"
+         ultimately have "Th th'' \<in> ancestors (tRAG (e#s)) (Th th)"
                        by (auto simp:ancestors_def)
          with assms show ?thesis by auto
       qed
     qed
     from subtree_insert_next[OF this]
-    have "subtree (tRAG s' \<union> {(Th th, Th th')}) (Th th'') = subtree (tRAG s') (Th th'')" .
+    have "subtree (tRAG s \<union> {(Th th, Th holder)}) (Th th'') = subtree (tRAG s) (Th th'')" .
     from this[folded tRAG_s] show ?thesis .
   qed
   show ?thesis by (unfold cp_alt_def1 h preced_kept, simp)
 qed
 
 lemma cp_gen_update_stop: (* ddd *)
-  assumes "u \<in> ancestors (tRAG s) (Th th)"
-  and "cp_gen s u = cp_gen s' u"
-  and "y \<in> ancestors (tRAG s) u"
-  shows "cp_gen s y = cp_gen s' y"
+  assumes "u \<in> ancestors (tRAG (e#s)) (Th th)"
+  and "cp_gen (e#s) u = cp_gen s u"
+  and "y \<in> ancestors (tRAG (e#s)) u"
+  shows "cp_gen (e#s) y = cp_gen s y"
   using assms(3)
-proof(induct rule:wf_induct[OF vat_s.fsbttRAGs.wf])
+proof(induct rule:wf_induct[OF vat_e.fsbttRAGs.wf])
   case (1 x)
   show ?case (is "?L = ?R")
   proof -
     from tRAG_ancestorsE[OF 1(2)]
     obtain th2 where eq_x: "x = Th th2" by blast
-    from vat_s.cp_gen_rec[OF this]
+    from vat_e.cp_gen_rec[OF this]
     have "?L = 
-          Max ({the_preced s th2} \<union> cp_gen s ` RTree.children (tRAG s) x)" .
+          Max ({the_preced (e#s) th2} \<union> cp_gen (e#s) ` RTree.children (tRAG (e#s)) x)" .
     also have "... = 
-          Max ({the_preced s' th2} \<union> cp_gen s' ` RTree.children (tRAG s') x)"
-  
+          Max ({the_preced s th2} \<union> cp_gen s ` RTree.children (tRAG s) x)"
     proof -
-      from preced_kept have "the_preced s th2 = the_preced s' th2" by simp
-      moreover have "cp_gen s ` RTree.children (tRAG s) x =
-                     cp_gen s' ` RTree.children (tRAG s') x"
+      from preced_kept have "the_preced (e#s) th2 = the_preced s th2" by simp
+      moreover have "cp_gen (e#s) ` RTree.children (tRAG (e#s)) x =
+                     cp_gen s ` RTree.children (tRAG s) x"
       proof -
-        have "RTree.children (tRAG s) x =  RTree.children (tRAG s') x"
+        have "RTree.children (tRAG (e#s)) x =  RTree.children (tRAG s) x"
         proof(unfold tRAG_s, rule children_union_kept)
-          have start: "(Th th, Th th') \<in> tRAG s"
+          have start: "(Th th, Th holder) \<in> tRAG (e#s)"
             by (unfold tRAG_s, auto)
           note x_u = 1(2)
-          show "x \<notin> Range {(Th th, Th th')}"
+          show "x \<notin> Range {(Th th, Th holder)}"
           proof
-            assume "x \<in> Range {(Th th, Th th')}"
-            hence eq_x: "x = Th th'" using RangeE by auto
+            assume "x \<in> Range {(Th th, Th holder)}"
+            hence eq_x: "x = Th holder" using RangeE by auto
             show False
-            proof(cases rule:vat_s.rtree_s.ancestors_headE[OF assms(1) start])
+            proof(cases rule:vat_e.ancestors_headE[OF assms(1) start])
               case 1
-              from x_u[folded this, unfolded eq_x] vat_s.acyclic_tRAG
+              from x_u[folded this, unfolded eq_x] vat_e.acyclic_tRAG
               show ?thesis by (auto simp:ancestors_def acyclic_def)
             next
               case 2
               with x_u[unfolded eq_x]
-              have "(Th th', Th th') \<in> (tRAG s)^+" by (auto simp:ancestors_def)
-              with vat_s.acyclic_tRAG show ?thesis by (auto simp:acyclic_def)
+              have "(Th holder, Th holder) \<in> (tRAG (e#s))^+" by (auto simp:ancestors_def)
+              with vat_e.acyclic_tRAG show ?thesis by (auto simp:acyclic_def)
             qed
           qed
         qed
-        moreover have "cp_gen s ` RTree.children (tRAG s) x =
-                       cp_gen s' ` RTree.children (tRAG s) x" (is "?f ` ?A = ?g ` ?A")
+        moreover have "cp_gen (e#s) ` RTree.children (tRAG (e#s)) x =
+                       cp_gen s ` RTree.children (tRAG (e#s)) x" (is "?f ` ?A = ?g ` ?A")
         proof(rule f_image_eq)
           fix a
           assume a_in: "a \<in> ?A"
           from 1(2)
           show "?f a = ?g a"
-          proof(cases rule:vat_s.rtree_s.ancestors_childrenE[case_names in_ch out_ch])
+          proof(cases rule:vat_e.rtree_s.ancestors_childrenE[case_names in_ch out_ch])
              case in_ch
              show ?thesis
              proof(cases "a = u")
@@ -650,58 +483,58 @@
                 from assms(2)[folded this] show ?thesis .
              next
                 case False
-                have a_not_in: "a \<notin> ancestors (tRAG s) (Th th)"
+                have a_not_in: "a \<notin> ancestors (tRAG (e#s)) (Th th)"
                 proof
-                  assume a_in': "a \<in> ancestors (tRAG s) (Th th)"
+                  assume a_in': "a \<in> ancestors (tRAG (e#s)) (Th th)"
                   have "a = u"
-                  proof(rule vat_s.rtree_s.ancestors_children_unique)
-                    from a_in' a_in show "a \<in> ancestors (tRAG s) (Th th) \<inter> 
-                                          RTree.children (tRAG s) x" by auto
+                  proof(rule vat_e.rtree_s.ancestors_children_unique)
+                    from a_in' a_in show "a \<in> ancestors (tRAG (e#s)) (Th th) \<inter> 
+                                          RTree.children (tRAG (e#s)) x" by auto
                   next 
-                    from assms(1) in_ch show "u \<in> ancestors (tRAG s) (Th th) \<inter> 
-                                      RTree.children (tRAG s) x" by auto
+                    from assms(1) in_ch show "u \<in> ancestors (tRAG (e#s)) (Th th) \<inter> 
+                                      RTree.children (tRAG (e#s)) x" by auto
                   qed
                   with False show False by simp
                 qed
                 from a_in obtain th_a where eq_a: "a = Th th_a" 
                     by (unfold RTree.children_def tRAG_alt_def, auto)
                 from cp_kept[OF a_not_in[unfolded eq_a]]
-                have "cp s th_a = cp s' th_a" .
+                have "cp (e#s) th_a = cp s th_a" .
                 from this [unfolded cp_gen_def_cond[OF eq_a], folded eq_a]
                 show ?thesis .
              qed
           next
             case (out_ch z)
-            hence h: "z \<in> ancestors (tRAG s) u" "z \<in> RTree.children (tRAG s) x" by auto
+            hence h: "z \<in> ancestors (tRAG (e#s)) u" "z \<in> RTree.children (tRAG (e#s)) x" by auto
             show ?thesis
             proof(cases "a = z")
               case True
-              from h(2) have zx_in: "(z, x) \<in> (tRAG s)" by (auto simp:RTree.children_def)
+              from h(2) have zx_in: "(z, x) \<in> (tRAG (e#s))" by (auto simp:RTree.children_def)
               from 1(1)[rule_format, OF this h(1)]
-              have eq_cp_gen: "cp_gen s z = cp_gen s' z" .
+              have eq_cp_gen: "cp_gen (e#s) z = cp_gen s z" .
               with True show ?thesis by metis
             next
               case False
               from a_in obtain th_a where eq_a: "a = Th th_a"
                 by (auto simp:RTree.children_def tRAG_alt_def)
-              have "a \<notin> ancestors (tRAG s) (Th th)"
+              have "a \<notin> ancestors (tRAG (e#s)) (Th th)"
               proof
-                assume a_in': "a \<in> ancestors (tRAG s) (Th th)"
+                assume a_in': "a \<in> ancestors (tRAG (e#s)) (Th th)"
                 have "a = z"
-                proof(rule vat_s.rtree_s.ancestors_children_unique)
-                  from assms(1) h(1) have "z \<in> ancestors (tRAG s) (Th th)"
+                proof(rule vat_e.rtree_s.ancestors_children_unique)
+                  from assms(1) h(1) have "z \<in> ancestors (tRAG (e#s)) (Th th)"
                       by (auto simp:ancestors_def)
-                  with h(2) show " z \<in> ancestors (tRAG s) (Th th) \<inter> 
-                                       RTree.children (tRAG s) x" by auto
+                  with h(2) show " z \<in> ancestors (tRAG (e#s)) (Th th) \<inter> 
+                                       RTree.children (tRAG (e#s)) x" by auto
                 next
                   from a_in a_in'
-                  show "a \<in> ancestors (tRAG s) (Th th) \<inter> RTree.children (tRAG s) x"
+                  show "a \<in> ancestors (tRAG (e#s)) (Th th) \<inter> RTree.children (tRAG (e#s)) x"
                     by auto
                 qed
                 with False show False by auto
               qed
               from cp_kept[OF this[unfolded eq_a]]
-              have "cp s th_a = cp s' th_a" .
+              have "cp (e#s) th_a = cp s th_a" .
               from this[unfolded cp_gen_def_cond[OF eq_a], folded eq_a]
               show ?thesis .
             qed
@@ -712,21 +545,21 @@
       ultimately show ?thesis by simp
     qed
     also have "... = ?R"
-      by (fold vat_s'.cp_gen_rec[OF eq_x], simp)
+      by (fold cp_gen_rec[OF eq_x], simp)
     finally show ?thesis .
   qed
 qed
 
 lemma cp_up:
-  assumes "(Th th') \<in> ancestors (tRAG s) (Th th)"
-  and "cp s th' = cp s' th'"
-  and "(Th th'') \<in> ancestors (tRAG s) (Th th')"
-  shows "cp s th'' = cp s' th''"
+  assumes "(Th th') \<in> ancestors (tRAG (e#s)) (Th th)"
+  and "cp (e#s) th' = cp s th'"
+  and "(Th th'') \<in> ancestors (tRAG (e#s)) (Th th')"
+  shows "cp (e#s) th'' = cp s th''"
 proof -
-  have "cp_gen s (Th th'') = cp_gen s' (Th th'')"
+  have "cp_gen (e#s) (Th th'') = cp_gen s (Th th'')"
   proof(rule cp_gen_update_stop[OF assms(1) _ assms(3)])
     from assms(2) cp_gen_def_cond[OF refl[of "Th th'"]]
-    show "cp_gen s (Th th') = cp_gen s' (Th th')" by metis
+    show "cp_gen (e#s) (Th th') = cp_gen s (Th th')" by metis
   qed
   with cp_gen_def_cond[OF refl[of "Th th''"]]
   show ?thesis by metis
@@ -736,50 +569,32 @@
 
 section {* The @{term Create} operation *}
 
-locale step_create_cps =
-  fixes s' th prio s 
-  defines s_def : "s \<equiv> (Create th prio#s')"
-  assumes vt_s: "vt s"
-
-sublocale step_create_cps < vat_s: valid_trace "s"
-  by (unfold_locales, insert vt_s, simp)
+context valid_trace_create
+begin 
 
-sublocale step_create_cps < vat_s': valid_trace "s'"
-  by (unfold_locales, insert step_back_vt[OF vt_s[unfolded s_def]], simp)
-
-context step_create_cps
-begin
+interpretation vat_e: valid_trace "e#s"
+  by (unfold_locales, insert vt_e, simp)
 
-lemma RAG_kept: "RAG s = RAG s'"
-  by (unfold s_def RAG_create_unchanged, auto)
-
-lemma tRAG_kept: "tRAG s = tRAG s'"
-  by (unfold tRAG_alt_def RAG_kept, auto)
+lemma tRAG_kept: "tRAG (e#s) = tRAG s"
+  by (unfold tRAG_alt_def RAG_unchanged, auto)
 
 lemma preced_kept:
   assumes "th' \<noteq> th"
-  shows "the_preced s th' = the_preced s' th'"
-  by (unfold s_def the_preced_def preced_def, insert assms, auto)
+  shows "the_preced (e#s) th' = the_preced s th'"
+  by (unfold the_preced_def preced_def is_create, insert assms, auto)
 
-lemma th_not_in: "Th th \<notin> Field (tRAG s')"
-proof -
-  from vt_s[unfolded s_def]
-  have "PIP s' (Create th prio)" by (cases, simp)
-  hence "th \<notin> threads s'" by(cases, simp)
-  from vat_s'.not_in_thread_isolated[OF this]
-  have "Th th \<notin> Field (RAG s')" .
-  with tRAG_Field show ?thesis by auto
-qed
+lemma th_not_in: "Th th \<notin> Field (tRAG s)"
+  by (meson not_in_thread_isolated subsetCE tRAG_Field th_not_live_s)
 
 lemma eq_cp:
   assumes neq_th: "th' \<noteq> th"
-  shows "cp s th' = cp s' th'"
+  shows "cp (e#s) th' = cp s th'"
 proof -
-  have "(the_preced s \<circ> the_thread) ` subtree (tRAG s) (Th th') =
-        (the_preced s' \<circ> the_thread) ` subtree (tRAG s') (Th th')"
+  have "(the_preced (e#s) \<circ> the_thread) ` subtree (tRAG (e#s)) (Th th') =
+        (the_preced s \<circ> the_thread) ` subtree (tRAG s) (Th th')"
   proof(unfold tRAG_kept, rule f_image_eq)
     fix a
-    assume a_in: "a \<in> subtree (tRAG s') (Th th')"
+    assume a_in: "a \<in> subtree (tRAG s) (Th th')"
     then obtain th_a where eq_a: "a = Th th_a" 
     proof(cases rule:subtreeE)
       case 2
@@ -788,9 +603,9 @@
     qed auto
     have neq_th_a: "th_a \<noteq> th"
     proof -
-      have "(Th th) \<notin> subtree (tRAG s') (Th th')"
+      have "(Th th) \<notin> subtree (tRAG s) (Th th')"
       proof
-        assume "Th th \<in> subtree (tRAG s') (Th th')"
+        assume "Th th \<in> subtree (tRAG s) (Th th')"
         thus False
         proof(cases rule:subtreeE)
           case 2
@@ -802,99 +617,72 @@
       with a_in[unfolded eq_a] show ?thesis by auto
     qed
     from preced_kept[OF this]
-    show "(the_preced s \<circ> the_thread) a = (the_preced s' \<circ> the_thread) a"
+    show "(the_preced (e#s) \<circ> the_thread) a = (the_preced s \<circ> the_thread) a"
       by (unfold eq_a, simp)
   qed
   thus ?thesis by (unfold cp_alt_def1, simp)
 qed
 
-lemma children_of_th: "RTree.children (tRAG s) (Th th) = {}"
+lemma children_of_th: "RTree.children (tRAG (e#s)) (Th th) = {}"
 proof -
   { fix a
-    assume "a \<in> RTree.children (tRAG s) (Th th)"
-    hence "(a, Th th) \<in> tRAG s" by (auto simp:RTree.children_def)
+    assume "a \<in> RTree.children (tRAG (e#s)) (Th th)"
+    hence "(a, Th th) \<in> tRAG (e#s)" by (auto simp:RTree.children_def)
     with th_not_in have False 
      by (unfold Field_def tRAG_kept, auto)
   } thus ?thesis by auto
 qed
 
-lemma eq_cp_th: "cp s th = preced th s"
- by (unfold vat_s.cp_rec children_of_th, simp add:the_preced_def)
+lemma eq_cp_th: "cp (e#s) th = preced th (e#s)"
+ by (unfold vat_e.cp_rec children_of_th, simp add:the_preced_def)
 
 end
 
-locale step_exit_cps =
-  fixes s' th prio s 
-  defines s_def : "s \<equiv> Exit th # s'"
-  assumes vt_s: "vt s"
 
-sublocale step_exit_cps < vat_s: valid_trace "s"
-  by (unfold_locales, insert vt_s, simp)
-
-sublocale step_exit_cps < vat_s': valid_trace "s'"
-  by (unfold_locales, insert step_back_vt[OF vt_s[unfolded s_def]], simp)
-
-context step_exit_cps
+context valid_trace_exit
 begin
 
 lemma preced_kept:
   assumes "th' \<noteq> th"
-  shows "the_preced s th' = the_preced s' th'"
-  by (unfold s_def the_preced_def preced_def, insert assms, auto)
-
-lemma RAG_kept: "RAG s = RAG s'"
-  by (unfold s_def RAG_exit_unchanged, auto)
-
-lemma tRAG_kept: "tRAG s = tRAG s'"
-  by (unfold tRAG_alt_def RAG_kept, auto)
+  shows "the_preced (e#s) th' = the_preced s th'"
+  using assms
+  by (unfold the_preced_def is_exit preced_def, simp)
 
-lemma th_ready: "th \<in> readys s'"
-proof -
-  from vt_s[unfolded s_def]
-  have "PIP s' (Exit th)" by (cases, simp)
-  hence h: "th \<in> runing s' \<and> holdents s' th = {}" by (cases, metis)
-  thus ?thesis by (unfold runing_def, auto)
-qed
+lemma tRAG_kept: "tRAG (e#s) = tRAG s"
+  by (unfold tRAG_alt_def RAG_unchanged, auto)
 
-lemma th_holdents: "holdents s' th = {}"
+lemma th_RAG: "Th th \<notin> Field (RAG s)"
 proof -
- from vt_s[unfolded s_def]
-  have "PIP s' (Exit th)" by (cases, simp)
-  thus ?thesis by (cases, metis)
-qed
-
-lemma th_RAG: "Th th \<notin> Field (RAG s')"
-proof -
-  have "Th th \<notin> Range (RAG s')"
+  have "Th th \<notin> Range (RAG s)"
   proof
-    assume "Th th \<in> Range (RAG s')"
-    then obtain cs where "holding (wq s') th cs"
+    assume "Th th \<in> Range (RAG s)"
+    then obtain cs where "holding (wq s) th cs"
       by (unfold Range_iff s_RAG_def, auto)
-    with th_holdents[unfolded holdents_def]
-    show False by (unfold eq_holding, auto)
+    with holdents_th_s[unfolded holdents_def]
+    show False by (unfold holding_eq, auto)
   qed
-  moreover have "Th th \<notin> Domain (RAG s')"
+  moreover have "Th th \<notin> Domain (RAG s)"
   proof
-    assume "Th th \<in> Domain (RAG s')"
-    then obtain cs where "waiting (wq s') th cs"
+    assume "Th th \<in> Domain (RAG s)"
+    then obtain cs where "waiting (wq s) th cs"
       by (unfold Domain_iff s_RAG_def, auto)
-    with th_ready show False by (unfold readys_def eq_waiting, auto)
+    with th_ready_s show False by (unfold readys_def waiting_eq, auto)
   qed
   ultimately show ?thesis by (auto simp:Field_def)
 qed
 
-lemma th_tRAG: "(Th th) \<notin> Field (tRAG s')"
-  using th_RAG tRAG_Field[of s'] by auto
+lemma th_tRAG: "(Th th) \<notin> Field (tRAG s)"
+  using th_RAG tRAG_Field by auto
 
 lemma eq_cp:
   assumes neq_th: "th' \<noteq> th"
-  shows "cp s th' = cp s' th'"
+  shows "cp (e#s) th' = cp s th'"
 proof -
-  have "(the_preced s \<circ> the_thread) ` subtree (tRAG s) (Th th') =
-        (the_preced s' \<circ> the_thread) ` subtree (tRAG s') (Th th')"
+  have "(the_preced (e#s) \<circ> the_thread) ` subtree (tRAG (e#s)) (Th th') =
+        (the_preced s \<circ> the_thread) ` subtree (tRAG s) (Th th')"
   proof(unfold tRAG_kept, rule f_image_eq)
     fix a
-    assume a_in: "a \<in> subtree (tRAG s') (Th th')"
+    assume a_in: "a \<in> subtree (tRAG s) (Th th')"
     then obtain th_a where eq_a: "a = Th th_a" 
     proof(cases rule:subtreeE)
       case 2
@@ -903,14 +691,14 @@
     qed auto
     have neq_th_a: "th_a \<noteq> th"
     proof -
-      from vat_s'.readys_in_no_subtree[OF th_ready assms]
-      have "(Th th) \<notin> subtree (RAG s') (Th th')" .
-      with tRAG_subtree_RAG[of s' "Th th'"]
-      have "(Th th) \<notin> subtree (tRAG s') (Th th')" by auto
+      from readys_in_no_subtree[OF th_ready_s assms]
+      have "(Th th) \<notin> subtree (RAG s) (Th th')" .
+      with tRAG_subtree_RAG[of s "Th th'"]
+      have "(Th th) \<notin> subtree (tRAG s) (Th th')" by auto
       with a_in[unfolded eq_a] show ?thesis by auto
     qed
     from preced_kept[OF this]
-    show "(the_preced s \<circ> the_thread) a = (the_preced s' \<circ> the_thread) a"
+    show "(the_preced (e#s) \<circ> the_thread) a = (the_preced s \<circ> the_thread) a"
       by (unfold eq_a, simp)
   qed
   thus ?thesis by (unfold cp_alt_def1, simp)
@@ -920,3 +708,4 @@
 
 end
 
+