--- a/CpsG.thy~ Wed Jan 13 15:22:14 2016 +0000
+++ b/CpsG.thy~ Wed Jan 13 23:39:59 2016 +0800
@@ -1,47 +1,3208 @@
-section {*
- This file contains lemmas used to guide the recalculation of current precedence
- after every system call (or system operation)
+theory CpsG
+imports PIPDefs
+begin
+
+(* I am going to use this file as a start point to retrofiting
+ PIPBasics.thy, which is originally called CpsG.ghy *)
+
+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
+
+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 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 ind [consumes 0, case_names Nil Cons, induct type]:
+ assumes "PP []"
+ and "(\<And>s e. valid_trace s \<Longrightarrow> valid_trace (e#s) \<Longrightarrow>
+ PP s \<Longrightarrow> PIP s e \<Longrightarrow> PP (e # s))"
+ shows "PP s"
+proof(rule vt.induct[OF vt])
+ from assms(1) show "PP []" .
+next
+ fix s e
+ assume h: "vt s" "PP s" "PIP s e"
+ show "PP (e # s)"
+ proof(cases rule:assms(2))
+ from h(1) show v1: "valid_trace s" by (unfold_locales, simp)
+ next
+ from h(1,3) have "vt (e#s)" by auto
+ thus "valid_trace (e # s)" by (unfold_locales, simp)
+ qed (insert h, auto)
+qed
+
+lemma wq_distinct: "distinct (wq s cs)"
+proof(induct rule:ind)
+ case (Cons s e)
+ from Cons(4,3)
+ show ?case
+ proof(induct)
+ case (thread_P th s cs1)
+ show ?case
+ proof(cases "cs = cs1")
+ case True
+ thus ?thesis (is "distinct ?L")
+ proof -
+ have "?L = wq_fun (schs s) cs1 @ [th]" using True
+ by (simp add:wq_def wf_def Let_def split:list.splits)
+ moreover have "distinct ..."
+ proof -
+ have "th \<notin> set (wq_fun (schs s) cs1)"
+ proof
+ assume otherwise: "th \<in> set (wq_fun (schs s) cs1)"
+ from runing_head[OF thread_P(1) this]
+ have "th = hd (wq_fun (schs s) cs1)" .
+ hence "(Cs cs1, Th th) \<in> (RAG s)" using otherwise
+ by (simp add:s_RAG_def s_holding_def wq_def cs_holding_def)
+ with thread_P(2) show False by auto
+ qed
+ moreover have "distinct (wq_fun (schs s) cs1)"
+ using True thread_P wq_def by auto
+ ultimately show ?thesis by auto
+ qed
+ ultimately show ?thesis by simp
+ qed
+ next
+ case False
+ with thread_P(3)
+ show ?thesis
+ by (auto simp:wq_def wf_def Let_def split:list.splits)
+ qed
+ next
+ case (thread_V th s cs1)
+ thus ?case
+ proof(cases "cs = cs1")
+ case True
+ show ?thesis (is "distinct ?L")
+ proof(cases "(wq s cs)")
+ case Nil
+ thus ?thesis
+ by (auto simp:wq_def wf_def Let_def split:list.splits)
+ next
+ case (Cons w_hd w_tl)
+ moreover have "distinct (SOME q. distinct q \<and> set q = set w_tl)"
+ proof(rule someI2)
+ from thread_V(3)[unfolded Cons]
+ show "distinct w_tl \<and> set w_tl = set w_tl" by auto
+ qed auto
+ ultimately show ?thesis
+ by (auto simp:wq_def wf_def Let_def True split:list.splits)
+ qed
+ next
+ case False
+ with thread_V(3)
+ show ?thesis
+ by (auto simp:wq_def wf_def Let_def split:list.splits)
+ qed
+ qed (insert Cons, auto simp: wq_def Let_def split:list.splits)
+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
+
+text {*
+ The following lemmas is also obvious and shallow. It says
+ that only running thread can request for a critical resource
+ and that the requested resource must be one which is
+ not current held by the thread.
+*}
+
+lemma p_pre: "\<lbrakk>vt ((P thread cs)#s)\<rbrakk> \<Longrightarrow>
+ thread \<in> runing s \<and> (Cs cs, Th thread) \<notin> (RAG s)^+"
+apply (ind_cases "vt ((P thread cs)#s)")
+apply (ind_cases "step s (P thread cs)")
+by auto
+
+lemma abs1:
+ assumes ein: "e \<in> set es"
+ and neq: "hd es \<noteq> hd (es @ [x])"
+ shows "False"
+proof -
+ from ein have "es \<noteq> []" by auto
+ then obtain e ess where "es = e # ess" by (cases es, auto)
+ with neq show ?thesis by auto
+qed
+
+lemma q_head: "Q (hd es) \<Longrightarrow> hd es = hd [th\<leftarrow>es . Q th]"
+ by (cases es, auto)
+
+inductive_cases evt_cons: "vt (a#s)"
+
+context valid_trace_e
+begin
+
+lemma abs2:
+ assumes inq: "thread \<in> set (wq s cs)"
+ and nh: "thread = hd (wq s cs)"
+ and qt: "thread \<noteq> hd (wq (e#s) cs)"
+ and inq': "thread \<in> set (wq (e#s) cs)"
+ shows "False"
+proof -
+ from vt_e assms show "False"
+ apply (cases e)
+ apply ((simp split:if_splits add:Let_def wq_def)[1])+
+ apply (insert abs1, fast)[1]
+ apply (auto simp:wq_def simp:Let_def split:if_splits list.splits)
+ proof -
+ fix th qs
+ assume vt: "vt (V th cs # s)"
+ and th_in: "thread \<in> set (SOME q. distinct q \<and> set q = set qs)"
+ and eq_wq: "wq_fun (schs s) cs = thread # qs"
+ show "False"
+ proof -
+ from wq_distinct[of cs]
+ and eq_wq[folded wq_def] have "distinct (thread#qs)" by simp
+ moreover have "thread \<in> set qs"
+ proof -
+ have "set (SOME q. distinct q \<and> set q = set qs) = set qs"
+ proof(rule someI2)
+ from wq_distinct [of cs]
+ and eq_wq [folded wq_def]
+ show "distinct qs \<and> set qs = set qs" by auto
+ next
+ fix x assume "distinct x \<and> set x = set qs"
+ thus "set x = set qs" by auto
+ qed
+ with th_in show ?thesis by auto
+ qed
+ ultimately show ?thesis by auto
+ qed
+ qed
+qed
+
+end
+
+
+context valid_trace
+begin
+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)
+ 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
+end
+
+
+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)
+
+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: (* ccc *)
+ 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 i1 i2
+ let ?i3 = "Suc i2"
+ assume lt12: "i1 < i2"
+ and "i1 < length s" "i2 < length s"
+ hence le_i3: "?i3 \<le> length s" by auto
+ from moment_plus [OF this]
+ obtain e where eq_m: "moment ?i3 s = e#moment i2 s" by auto
+ have "i2 < ?i3" 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(cases "thread \<in> set (wq (moment t2 s) cs2)")
+ case True
+ from True and np2 have eq_th: "thread = hd (wq (moment t2 s) cs2)"
+ by auto
+ from vt_e.abs2 [OF True eq_th h2 h1]
+ show ?thesis by auto
+ next
+ case False
+ from vt_e.block_pre[OF False h1]
+ have "e = P thread cs2" .
+ with vt_e.vt_e have "vt ((P thread cs2)# moment t2 s)" by simp
+ from p_pre [OF this] have "thread \<in> runing (moment t2 s)" by simp
+ with runing_ready have "thread \<in> readys (moment t2 s)" by auto
+ with nn1 [rule_format, OF lt12]
+ show ?thesis by (simp add:readys_def wq_def s_waiting_def, auto)
+ qed
+ }
+ show ?thesis
+ proof -
+ {
+ assume lt12: "t1 < t2"
+ let ?t3 = "Suc t2"
+ from lt2 have le_t3: "?t3 \<le> length s" by auto
+ from moment_plus [OF this]
+ obtain e where eq_m: "moment ?t3 s = e#moment t2 s" by auto
+ have "t2 < ?t3" by simp
+ from nn2 [rule_format, OF this] and eq_m
+ have h1: "thread \<in> set (wq (e#moment t2 s) cs2)" and
+ h2: "thread \<noteq> hd (wq (e#moment t2 s) cs2)" by auto
+ have "vt (e#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(cases "thread \<in> set (wq (moment t2 s) cs2)")
+ case True
+ from True and np2 have eq_th: "thread = hd (wq (moment t2 s) cs2)"
+ by auto
+ from vt_e.abs2 [OF True eq_th h2 h1]
+ show ?thesis by auto
+ next
+ case False
+ from vt_e.block_pre[OF False h1]
+ have "e = P thread cs2" .
+ with vt_e.vt_e have "vt ((P thread cs2)# moment t2 s)" by simp
+ from p_pre [OF this] have "thread \<in> runing (moment t2 s)" by simp
+ with runing_ready have "thread \<in> readys (moment t2 s)" by auto
+ with nn1 [rule_format, OF lt12]
+ show ?thesis by (simp add:readys_def wq_def s_waiting_def, auto)
+ qed
+ } moreover {
+ assume lt12: "t2 < t1"
+ let ?t3 = "Suc t1"
+ from lt1 have le_t3: "?t3 \<le> length s" by auto
+ from moment_plus [OF this]
+ obtain e where eq_m: "moment ?t3 s = e#moment t1 s" by auto
+ have lt_t3: "t1 < ?t3" by simp
+ from nn1 [rule_format, OF this] and eq_m
+ have h1: "thread \<in> set (wq (e#moment t1 s) cs1)" and
+ h2: "thread \<noteq> hd (wq (e#moment t1 s) cs1)" by auto
+ have "vt (e#moment t1 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 t1 s" e
+ by (unfold_locales, auto, cases, auto)
+ have ?thesis
+ proof(cases "thread \<in> set (wq (moment t1 s) cs1)")
+ case True
+ from True and np1 have eq_th: "thread = hd (wq (moment t1 s) cs1)"
+ by auto
+ from vt_e.abs2 True eq_th h2 h1
+ show ?thesis by auto
+ next
+ case False
+ from vt_e.block_pre [OF False h1]
+ have "e = P thread cs1" .
+ with vt_e.vt_e have "vt ((P thread cs1)# moment t1 s)" by simp
+ from p_pre [OF this] have "thread \<in> runing (moment t1 s)" by simp
+ with runing_ready have "thread \<in> readys (moment t1 s)" by auto
+ with nn2 [rule_format, OF lt12]
+ show ?thesis by (simp add:readys_def wq_def s_waiting_def, auto)
+ qed
+ } moreover {
+ assume eqt12: "t1 = t2"
+ let ?t3 = "Suc t1"
+ from lt1 have le_t3: "?t3 \<le> length s" by auto
+ from moment_plus [OF this]
+ obtain e where eq_m: "moment ?t3 s = e#moment t1 s" by auto
+ have lt_t3: "t1 < ?t3" by simp
+ from nn1 [rule_format, OF this] and eq_m
+ have h1: "thread \<in> set (wq (e#moment t1 s) cs1)" and
+ h2: "thread \<noteq> hd (wq (e#moment t1 s) cs1)" by auto
+ have vt_e: "vt (e#moment t1 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 t1 s" e
+ by (unfold_locales, auto, cases, auto)
+ have ?thesis
+ proof(cases "thread \<in> set (wq (moment t1 s) cs1)")
+ case True
+ from True and np1 have eq_th: "thread = hd (wq (moment t1 s) cs1)"
+ by auto
+ from vt_e.abs2 [OF True eq_th h2 h1]
+ show ?thesis by auto
+ next
+ case False
+ from vt_e.block_pre [OF False h1]
+ have eq_e1: "e = P thread cs1" .
+ have lt_t3: "t1 < ?t3" by simp
+ with eqt12 have "t2 < ?t3" by simp
+ from nn2 [rule_format, OF this] and eq_m and eqt12
+ have h1: "thread \<in> set (wq (e#moment t2 s) cs2)" and
+ h2: "thread \<noteq> hd (wq (e#moment t2 s) cs2)" by auto
+ show ?thesis
+ proof(cases "thread \<in> set (wq (moment t2 s) cs2)")
+ case True
+ from True and np2 have eq_th: "thread = hd (wq (moment t2 s) cs2)"
+ by auto
+ from vt_e and eqt12 have "vt (e#moment t2 s)" by simp
+ then interpret vt_e2: valid_trace_e "moment t2 s" e
+ by (unfold_locales, auto, cases, auto)
+ from vt_e2.abs2 [OF True eq_th h2 h1]
+ show ?thesis .
+ next
+ case False
+ have "vt (e#moment t2 s)"
+ proof -
+ from vt_moment eqt12
+ have "vt (moment (Suc t2) s)" by auto
+ with eq_m eqt12 show ?thesis by simp
+ qed
+ then interpret vt_e2: valid_trace_e "moment t2 s" e
+ by (unfold_locales, auto, cases, auto)
+ from vt_e2.block_pre [OF False h1]
+ have "e = P thread cs2" .
+ with eq_e1 neq12 show ?thesis by auto
+ qed
+ qed
+ } ultimately show ?thesis by arith
+ qed
+qed
+
+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
+
+(* An aux lemma used later *)
+lemma unique_minus:
+ assumes unique: "\<And> a b c. \<lbrakk>(a, b) \<in> r; (a, c) \<in> r\<rbrakk> \<Longrightarrow> b = c"
+ and xy: "(x, y) \<in> r"
+ and xz: "(x, z) \<in> r^+"
+ and neq: "y \<noteq> z"
+ shows "(y, z) \<in> r^+"
+proof -
+ from xz and neq show ?thesis
+ proof(induct)
+ case (base ya)
+ have "(x, ya) \<in> r" by fact
+ from unique [OF xy this] have "y = ya" .
+ with base show ?case by auto
+ next
+ case (step ya z)
+ show ?case
+ proof(cases "y = ya")
+ case True
+ from step True show ?thesis by simp
+ next
+ case False
+ from step False
+ show ?thesis by auto
+ qed
+ qed
+qed
+
+lemma unique_base:
+ assumes unique: "\<And> a b c. \<lbrakk>(a, b) \<in> r; (a, c) \<in> r\<rbrakk> \<Longrightarrow> b = c"
+ and xy: "(x, y) \<in> r"
+ and xz: "(x, z) \<in> r^+"
+ and neq_yz: "y \<noteq> z"
+ shows "(y, z) \<in> r^+"
+proof -
+ from xz neq_yz show ?thesis
+ proof(induct)
+ case (base ya)
+ from xy unique base show ?case by auto
+ next
+ case (step ya z)
+ show ?case
+ proof(cases "y = ya")
+ case True
+ from True step show ?thesis by auto
+ next
+ case False
+ from False step
+ have "(y, ya) \<in> r\<^sup>+" by auto
+ with step show ?thesis by auto
+ qed
+ qed
+qed
+
+lemma unique_chain:
+ assumes unique: "\<And> a b c. \<lbrakk>(a, b) \<in> r; (a, c) \<in> r\<rbrakk> \<Longrightarrow> b = c"
+ and xy: "(x, y) \<in> r^+"
+ and xz: "(x, z) \<in> r^+"
+ and neq_yz: "y \<noteq> z"
+ shows "(y, z) \<in> r^+ \<or> (z, y) \<in> r^+"
+proof -
+ from xy xz neq_yz show ?thesis
+ proof(induct)
+ case (base y)
+ have h1: "(x, y) \<in> r" and h2: "(x, z) \<in> r\<^sup>+" and h3: "y \<noteq> z" using base by auto
+ from unique_base [OF _ h1 h2 h3] and unique show ?case by auto
+ next
+ case (step y za)
+ show ?case
+ proof(cases "y = z")
+ case True
+ from True step show ?thesis by auto
+ next
+ case False
+ from False step have "(y, z) \<in> r\<^sup>+ \<or> (z, y) \<in> r\<^sup>+" by auto
+ thus ?thesis
+ proof
+ assume "(z, y) \<in> r\<^sup>+"
+ with step have "(z, za) \<in> r\<^sup>+" by auto
+ thus ?thesis by auto
+ next
+ assume h: "(y, z) \<in> r\<^sup>+"
+ from step have yza: "(y, za) \<in> r" by simp
+ from step have "za \<noteq> z" by simp
+ from unique_minus [OF _ yza h this] and unique
+ have "(za, z) \<in> r\<^sup>+" by auto
+ thus ?thesis by auto
+ qed
+ qed
+ qed
+qed
+
+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 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 RAG_exit_unchanged: "(RAG (Exit th # s)) = RAG s"
+apply (unfold s_RAG_def s_waiting_def wq_def)
+by (simp add:Let_def)
+
+
+text {*
+ The following lemmas are used in the proof of
+ lemma @{text "step_RAG_v"}, which characterizes how the @{text "RAG"} is changed
+ by @{text "V"}-events.
+ However, since our model is very concise, such seemingly obvious lemmas need to be derived from scratch,
+ starting from the model definitions.
*}
-theory CpsG
-imports PrioG Max RTree
+lemma step_v_hold_inv[elim_format]:
+ "\<And>c t. \<lbrakk>vt (V th cs # s);
+ \<not> holding (wq s) t c; holding (wq (V th cs # s)) t c\<rbrakk> \<Longrightarrow>
+ next_th s th cs t \<and> c = cs"
+proof -
+ fix c t
+ assume vt: "vt (V th cs # s)"
+ and nhd: "\<not> holding (wq s) t c"
+ and hd: "holding (wq (V th cs # s)) t c"
+ show "next_th s th cs t \<and> c = cs"
+ proof(cases "c = cs")
+ case False
+ with nhd hd show ?thesis
+ by (unfold cs_holding_def wq_def, auto simp:Let_def)
+ next
+ case True
+ with step_back_step [OF vt]
+ have "step s (V th c)" by simp
+ hence "next_th s th cs t"
+ proof(cases)
+ assume "holding s th c"
+ with nhd hd show ?thesis
+ apply (unfold s_holding_def cs_holding_def wq_def next_th_def,
+ auto simp:Let_def split:list.splits if_splits)
+ proof -
+ assume " hd (SOME q. distinct q \<and> q = []) \<in> set (SOME q. distinct q \<and> q = [])"
+ moreover have "\<dots> = set []"
+ proof(rule someI2)
+ show "distinct [] \<and> [] = []" by auto
+ next
+ fix x assume "distinct x \<and> x = []"
+ thus "set x = set []" by auto
+ qed
+ ultimately show False by auto
+ next
+ assume " hd (SOME q. distinct q \<and> q = []) \<in> set (SOME q. distinct q \<and> q = [])"
+ moreover have "\<dots> = set []"
+ proof(rule someI2)
+ show "distinct [] \<and> [] = []" by auto
+ next
+ fix x assume "distinct x \<and> x = []"
+ thus "set x = set []" by auto
+ qed
+ ultimately show False by auto
+ qed
+ qed
+ with True show ?thesis by auto
+ qed
+qed
+
+text {*
+ The following @{text "step_v_wait_inv"} is also an obvious lemma, which, however, needs to be
+ derived from scratch, which confirms the correctness of the definition of @{text "next_th"}.
+*}
+lemma step_v_wait_inv[elim_format]:
+ "\<And>t c. \<lbrakk>vt (V th cs # s); \<not> waiting (wq (V th cs # s)) t c; waiting (wq s) t c
+ \<rbrakk>
+ \<Longrightarrow> (next_th s th cs t \<and> cs = c)"
+proof -
+ fix t c
+ assume vt: "vt (V th cs # s)"
+ and nw: "\<not> waiting (wq (V th cs # s)) t c"
+ and wt: "waiting (wq s) t c"
+ from vt interpret vt_v: valid_trace_e s "V th cs"
+ by (cases, unfold_locales, simp)
+ show "next_th s th cs t \<and> cs = c"
+ proof(cases "cs = c")
+ case False
+ with nw wt show ?thesis
+ by (auto simp:cs_waiting_def wq_def Let_def)
+ next
+ case True
+ from nw[folded True] wt[folded True]
+ have "next_th s th cs t"
+ apply (unfold next_th_def, auto simp:cs_waiting_def wq_def Let_def split:list.splits)
+ proof -
+ fix a list
+ assume t_in: "t \<in> set list"
+ and t_ni: "t \<notin> set (SOME q. distinct q \<and> set q = set list)"
+ and eq_wq: "wq_fun (schs s) cs = a # list"
+ have " set (SOME q. distinct q \<and> set q = set list) = set list"
+ proof(rule someI2)
+ from vt_v.wq_distinct[of cs] and eq_wq[folded wq_def]
+ show "distinct list \<and> set list = set list" by auto
+ next
+ show "\<And>x. distinct x \<and> set x = set list \<Longrightarrow> set x = set list"
+ by auto
+ qed
+ with t_ni and t_in show "a = th" by auto
+ next
+ fix a list
+ assume t_in: "t \<in> set list"
+ and t_ni: "t \<notin> set (SOME q. distinct q \<and> set q = set list)"
+ and eq_wq: "wq_fun (schs s) cs = a # list"
+ have " set (SOME q. distinct q \<and> set q = set list) = set list"
+ proof(rule someI2)
+ from vt_v.wq_distinct[of cs] and eq_wq[folded wq_def]
+ show "distinct list \<and> set list = set list" by auto
+ next
+ show "\<And>x. distinct x \<and> set x = set list \<Longrightarrow> set x = set list"
+ by auto
+ qed
+ with t_ni and t_in show "t = hd (SOME q. distinct q \<and> set q = set list)" by auto
+ next
+ fix a list
+ assume eq_wq: "wq_fun (schs s) cs = a # list"
+ from step_back_step[OF vt]
+ show "a = th"
+ proof(cases)
+ assume "holding s th cs"
+ with eq_wq show ?thesis
+ by (unfold s_holding_def wq_def, auto)
+ qed
+ qed
+ with True show ?thesis by simp
+ qed
+qed
+
+lemma step_v_not_wait[consumes 3]:
+ "\<lbrakk>vt (V th cs # s); next_th s th cs t; waiting (wq (V th cs # s)) t cs\<rbrakk> \<Longrightarrow> False"
+ by (unfold next_th_def cs_waiting_def wq_def, auto simp:Let_def)
+
+lemma step_v_release:
+ "\<lbrakk>vt (V th cs # s); holding (wq (V th cs # s)) th cs\<rbrakk> \<Longrightarrow> False"
+proof -
+ assume vt: "vt (V th cs # s)"
+ and hd: "holding (wq (V th cs # s)) th cs"
+ from vt interpret vt_v: valid_trace_e s "V th cs"
+ by (cases, unfold_locales, simp+)
+ from step_back_step [OF vt] and hd
+ show "False"
+ proof(cases)
+ assume "holding (wq (V th cs # s)) th cs" and "holding s th cs"
+ thus ?thesis
+ apply (unfold s_holding_def wq_def cs_holding_def)
+ apply (auto simp:Let_def split:list.splits)
+ proof -
+ fix list
+ assume eq_wq[folded wq_def]:
+ "wq_fun (schs s) cs = hd (SOME q. distinct q \<and> set q = set list) # list"
+ and hd_in: "hd (SOME q. distinct q \<and> set q = set list)
+ \<in> set (SOME q. distinct q \<and> set q = set list)"
+ have "set (SOME q. distinct q \<and> set q = set list) = set list"
+ proof(rule someI2)
+ from vt_v.wq_distinct[of cs] and eq_wq
+ show "distinct list \<and> set list = set list" by auto
+ next
+ show "\<And>x. distinct x \<and> set x = set list \<Longrightarrow> set x = set list"
+ by auto
+ qed
+ moreover have "distinct (hd (SOME q. distinct q \<and> set q = set list) # list)"
+ proof -
+ from vt_v.wq_distinct[of cs] and eq_wq
+ show ?thesis by auto
+ qed
+ moreover note eq_wq and hd_in
+ ultimately show "False" by auto
+ qed
+ qed
+qed
+
+lemma step_v_get_hold:
+ "\<And>th'. \<lbrakk>vt (V th cs # s); \<not> holding (wq (V th cs # s)) th' cs; next_th s th cs th'\<rbrakk> \<Longrightarrow> False"
+ apply (unfold cs_holding_def next_th_def wq_def,
+ auto simp:Let_def)
+proof -
+ fix rest
+ assume vt: "vt (V th cs # s)"
+ and eq_wq[folded wq_def]: " wq_fun (schs s) cs = th # rest"
+ and nrest: "rest \<noteq> []"
+ and ni: "hd (SOME q. distinct q \<and> set q = set rest)
+ \<notin> set (SOME q. distinct q \<and> set q = set rest)"
+ from vt interpret vt_v: valid_trace_e s "V th cs"
+ by (cases, unfold_locales, simp+)
+ have "(SOME q. distinct q \<and> set q = set rest) \<noteq> []"
+ proof(rule someI2)
+ from vt_v.wq_distinct[of cs] and eq_wq
+ show "distinct rest \<and> set rest = set rest" by auto
+ next
+ fix x assume "distinct x \<and> set x = set rest"
+ hence "set x = set rest" by auto
+ with nrest
+ show "x \<noteq> []" by (case_tac x, auto)
+ qed
+ with ni show "False" by auto
+qed
+
+lemma step_v_release_inv[elim_format]:
+"\<And>c t. \<lbrakk>vt (V th cs # s); \<not> holding (wq (V th cs # s)) t c; holding (wq s) t c\<rbrakk> \<Longrightarrow>
+ c = cs \<and> t = th"
+ apply (unfold cs_holding_def wq_def, auto simp:Let_def split:if_splits list.splits)
+ proof -
+ fix a list
+ assume vt: "vt (V th cs # s)" and eq_wq: "wq_fun (schs s) cs = a # list"
+ from step_back_step [OF vt] show "a = th"
+ proof(cases)
+ assume "holding s th cs" with eq_wq
+ show ?thesis
+ by (unfold s_holding_def wq_def, auto)
+ qed
+ next
+ fix a list
+ assume vt: "vt (V th cs # s)" and eq_wq: "wq_fun (schs s) cs = a # list"
+ from step_back_step [OF vt] show "a = th"
+ proof(cases)
+ assume "holding s th cs" with eq_wq
+ show ?thesis
+ by (unfold s_holding_def wq_def, auto)
+ qed
+ qed
+
+lemma step_v_waiting_mono:
+ "\<And>t c. \<lbrakk>vt (V th cs # s); waiting (wq (V th cs # s)) t c\<rbrakk> \<Longrightarrow> waiting (wq s) t c"
+proof -
+ fix t c
+ let ?s' = "(V th cs # s)"
+ assume vt: "vt ?s'"
+ and wt: "waiting (wq ?s') t c"
+ from vt interpret vt_v: valid_trace_e s "V th cs"
+ by (cases, unfold_locales, simp+)
+ show "waiting (wq s) t c"
+ proof(cases "c = cs")
+ case False
+ assume neq_cs: "c \<noteq> cs"
+ hence "waiting (wq ?s') t c = waiting (wq s) t c"
+ by (unfold cs_waiting_def wq_def, auto simp:Let_def)
+ with wt show ?thesis by simp
+ next
+ case True
+ with wt show ?thesis
+ apply (unfold cs_waiting_def wq_def, auto simp:Let_def split:list.splits)
+ proof -
+ fix a list
+ assume not_in: "t \<notin> set list"
+ and is_in: "t \<in> set (SOME q. distinct q \<and> set q = set list)"
+ and eq_wq: "wq_fun (schs s) cs = a # list"
+ have "set (SOME q. distinct q \<and> set q = set list) = set list"
+ proof(rule someI2)
+ from vt_v.wq_distinct [of cs]
+ and eq_wq[folded wq_def]
+ show "distinct list \<and> set list = set list" by auto
+ next
+ fix x assume "distinct x \<and> set x = set list"
+ thus "set x = set list" by auto
+ qed
+ with not_in is_in show "t = a" by auto
+ next
+ fix list
+ assume is_waiting: "waiting (wq (V th cs # s)) t cs"
+ and eq_wq: "wq_fun (schs s) cs = t # list"
+ hence "t \<in> set list"
+ apply (unfold wq_def, auto simp:Let_def cs_waiting_def)
+ proof -
+ assume " t \<in> set (SOME q. distinct q \<and> set q = set list)"
+ moreover have "\<dots> = set list"
+ proof(rule someI2)
+ from vt_v.wq_distinct [of cs]
+ and eq_wq[folded wq_def]
+ show "distinct list \<and> set list = set list" by auto
+ next
+ fix x assume "distinct x \<and> set x = set list"
+ thus "set x = set list" by auto
+ qed
+ ultimately show "t \<in> set list" by simp
+ qed
+ with eq_wq and vt_v.wq_distinct [of cs, unfolded wq_def]
+ show False by auto
+ qed
+ qed
+qed
+
+text {* (* ddd *)
+ The following @{text "step_RAG_v"} lemma charaterizes how @{text "RAG"} is changed
+ with the happening of @{text "V"}-events:
+*}
+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'}"
+ apply (insert vt, unfold s_RAG_def)
+ apply (auto split:if_splits list.splits simp:Let_def)
+ apply (auto elim: step_v_waiting_mono step_v_hold_inv
+ step_v_release step_v_wait_inv
+ step_v_get_hold step_v_release_inv)
+ apply (erule_tac step_v_not_wait, auto)
+ done
+
+text {*
+ The following @{text "step_RAG_p"} lemma charaterizes how @{text "RAG"} is changed
+ with the happening of @{text "P"}-events:
+*}
+lemma step_RAG_p:
+ "vt (P th cs#s) \<Longrightarrow>
+ RAG (P th cs # s) = (if (wq s cs = []) then RAG s \<union> {(Cs cs, Th th)}
+ else RAG s \<union> {(Th th, Cs cs)})"
+ apply(simp only: s_RAG_def wq_def)
+ apply (auto split:list.splits prod.splits simp:Let_def wq_def cs_waiting_def cs_holding_def)
+ apply(case_tac "csa = cs", auto)
+ apply(fold wq_def)
+ apply(drule_tac step_back_step)
+ apply(ind_cases " step s (P (hd (wq s cs)) cs)")
+ apply(simp add:s_RAG_def wq_def cs_holding_def)
+ apply(auto)
+ done
+
+
+lemma RAG_target_th: "(Th th, x) \<in> RAG (s::state) \<Longrightarrow> \<exists> cs. x = Cs cs"
+ by (unfold s_RAG_def, auto)
+
+context valid_trace
+begin
+
+text {*
+ The following lemma shows that @{text "RAG"} is acyclic.
+ The overall structure is by induction on the formation of @{text "vt s"}
+ and then case analysis on event @{text "e"}, where the non-trivial cases
+ for those for @{text "V"} and @{text "P"} events.
+*}
+lemma acyclic_RAG:
+ shows "acyclic (RAG s)"
+using vt
+proof(induct)
+ case (vt_cons s e)
+ interpret vt_s: valid_trace s using vt_cons(1)
+ by (unfold_locales, simp)
+ assume ih: "acyclic (RAG s)"
+ and stp: "step s e"
+ and vt: "vt s"
+ show ?case
+ proof(cases e)
+ case (Create th prio)
+ with ih
+ show ?thesis by (simp add:RAG_create_unchanged)
+ next
+ case (Exit th)
+ with ih show ?thesis by (simp add:RAG_exit_unchanged)
+ next
+ case (V th cs)
+ from V vt stp have vtt: "vt (V th cs#s)" by auto
+ from step_RAG_v [OF this]
+ have eq_de:
+ "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 = (?A - ?B - ?C) \<union> ?D") by (simp add:V)
+ from ih have ac: "acyclic (?A - ?B - ?C)" by (auto elim:acyclic_subset)
+ from step_back_step [OF vtt]
+ have "step s (V th cs)" .
+ thus ?thesis
+ proof(cases)
+ assume "holding s th cs"
+ hence th_in: "th \<in> set (wq s cs)" and
+ eq_hd: "th = hd (wq s cs)" unfolding s_holding_def wq_def by auto
+ then obtain rest where
+ eq_wq: "wq s cs = th#rest"
+ by (cases "wq s cs", auto)
+ show ?thesis
+ proof(cases "rest = []")
+ case False
+ let ?th' = "hd (SOME q. distinct q \<and> set q = set rest)"
+ from eq_wq False have eq_D: "?D = {(Cs cs, Th ?th')}"
+ by (unfold next_th_def, auto)
+ let ?E = "(?A - ?B - ?C)"
+ have "(Th ?th', Cs cs) \<notin> ?E\<^sup>*"
+ proof
+ assume "(Th ?th', Cs cs) \<in> ?E\<^sup>*"
+ hence " (Th ?th', Cs cs) \<in> ?E\<^sup>+" by (simp add: rtrancl_eq_or_trancl)
+ from tranclD [OF this]
+ obtain x where th'_e: "(Th ?th', x) \<in> ?E" by blast
+ hence th_d: "(Th ?th', x) \<in> ?A" by simp
+ from RAG_target_th [OF this]
+ obtain cs' where eq_x: "x = Cs cs'" by auto
+ with th_d have "(Th ?th', Cs cs') \<in> ?A" by simp
+ hence wt_th': "waiting s ?th' cs'"
+ unfolding s_RAG_def s_waiting_def cs_waiting_def wq_def by simp
+ hence "cs' = cs"
+ proof(rule vt_s.waiting_unique)
+ from eq_wq vt_s.wq_distinct[of cs]
+ show "waiting s ?th' cs"
+ apply (unfold s_waiting_def wq_def, auto)
+ proof -
+ assume hd_in: "hd (SOME q. distinct q \<and> set q = set rest) \<notin> set rest"
+ and eq_wq: "wq_fun (schs s) cs = th # rest"
+ have "(SOME q. distinct q \<and> set q = set rest) \<noteq> []"
+ proof(rule someI2)
+ from vt_s.wq_distinct[of cs] and eq_wq
+ show "distinct rest \<and> set rest = set rest" unfolding wq_def by auto
+ next
+ fix x assume "distinct x \<and> set x = set rest"
+ with False show "x \<noteq> []" by auto
+ qed
+ hence "hd (SOME q. distinct q \<and> set q = set rest) \<in>
+ set (SOME q. distinct q \<and> set q = set rest)" by auto
+ moreover have "\<dots> = set rest"
+ proof(rule someI2)
+ from vt_s.wq_distinct[of cs] and eq_wq
+ show "distinct rest \<and> set rest = set rest" unfolding wq_def by auto
+ next
+ show "\<And>x. distinct x \<and> set x = set rest \<Longrightarrow> set x = set rest" by auto
+ qed
+ moreover note hd_in
+ ultimately show "hd (SOME q. distinct q \<and> set q = set rest) = th" by auto
+ next
+ assume hd_in: "hd (SOME q. distinct q \<and> set q = set rest) \<notin> set rest"
+ and eq_wq: "wq s cs = hd (SOME q. distinct q \<and> set q = set rest) # rest"
+ have "(SOME q. distinct q \<and> set q = set rest) \<noteq> []"
+ proof(rule someI2)
+ from vt_s.wq_distinct[of cs] and eq_wq
+ show "distinct rest \<and> set rest = set rest" by auto
+ next
+ fix x assume "distinct x \<and> set x = set rest"
+ with False show "x \<noteq> []" by auto
+ qed
+ hence "hd (SOME q. distinct q \<and> set q = set rest) \<in>
+ set (SOME q. distinct q \<and> set q = set rest)" by auto
+ moreover have "\<dots> = set rest"
+ proof(rule someI2)
+ from vt_s.wq_distinct[of cs] and eq_wq
+ show "distinct rest \<and> set rest = set rest" by auto
+ next
+ show "\<And>x. distinct x \<and> set x = set rest \<Longrightarrow> set x = set rest" by auto
+ qed
+ moreover note hd_in
+ ultimately show False by auto
+ qed
+ qed
+ with th'_e eq_x have "(Th ?th', Cs cs) \<in> ?E" by simp
+ with False
+ show "False" by (auto simp: next_th_def eq_wq)
+ qed
+ with acyclic_insert[symmetric] and ac
+ and eq_de eq_D show ?thesis by auto
+ next
+ case True
+ with eq_wq
+ have eq_D: "?D = {}"
+ by (unfold next_th_def, auto)
+ with eq_de ac
+ show ?thesis by auto
+ qed
+ qed
+ next
+ case (P th cs)
+ from P vt stp have vtt: "vt (P th cs#s)" by auto
+ from step_RAG_p [OF this] P
+ have "RAG (e # s) =
+ (if wq s cs = [] then RAG s \<union> {(Cs cs, Th th)} else
+ RAG s \<union> {(Th th, Cs cs)})" (is "?L = ?R")
+ by simp
+ moreover have "acyclic ?R"
+ proof(cases "wq s cs = []")
+ case True
+ hence eq_r: "?R = RAG s \<union> {(Cs cs, Th th)}" by simp
+ have "(Th th, Cs cs) \<notin> (RAG s)\<^sup>*"
+ proof
+ assume "(Th th, Cs cs) \<in> (RAG s)\<^sup>*"
+ hence "(Th th, Cs cs) \<in> (RAG s)\<^sup>+" by (simp add: rtrancl_eq_or_trancl)
+ from tranclD2 [OF this]
+ obtain x where "(x, Cs cs) \<in> RAG s" by auto
+ with True show False by (auto simp:s_RAG_def cs_waiting_def)
+ qed
+ with acyclic_insert ih eq_r show ?thesis by auto
+ next
+ case False
+ hence eq_r: "?R = RAG s \<union> {(Th th, Cs cs)}" by simp
+ have "(Cs cs, Th th) \<notin> (RAG s)\<^sup>*"
+ proof
+ assume "(Cs cs, Th th) \<in> (RAG s)\<^sup>*"
+ hence "(Cs cs, Th th) \<in> (RAG s)\<^sup>+" by (simp add: rtrancl_eq_or_trancl)
+ moreover from step_back_step [OF vtt] have "step s (P th cs)" .
+ ultimately show False
+ proof -
+ show " \<lbrakk>(Cs cs, Th th) \<in> (RAG s)\<^sup>+; step s (P th cs)\<rbrakk> \<Longrightarrow> False"
+ by (ind_cases "step s (P th cs)", simp)
+ qed
+ qed
+ with acyclic_insert ih eq_r show ?thesis by auto
+ qed
+ ultimately show ?thesis by simp
+ next
+ case (Set thread prio)
+ with ih
+ thm RAG_set_unchanged
+ show ?thesis by (simp add:RAG_set_unchanged)
+ qed
+ next
+ case vt_nil
+ show "acyclic (RAG ([]::state))"
+ by (auto simp: s_RAG_def cs_waiting_def
+ cs_holding_def wq_def acyclic_def)
+qed
+
+
+lemma finite_RAG:
+ shows "finite (RAG s)"
+proof -
+ from vt show ?thesis
+ proof(induct)
+ case (vt_cons s e)
+ interpret vt_s: valid_trace s using vt_cons(1)
+ by (unfold_locales, simp)
+ assume ih: "finite (RAG s)"
+ and stp: "step s e"
+ and vt: "vt s"
+ show ?case
+ proof(cases e)
+ case (Create th prio)
+ with ih
+ show ?thesis by (simp add:RAG_create_unchanged)
+ next
+ case (Exit th)
+ with ih show ?thesis by (simp add:RAG_exit_unchanged)
+ next
+ case (V th cs)
+ from V vt stp have vtt: "vt (V th cs#s)" by auto
+ from step_RAG_v [OF this]
+ have eq_de: "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 = (?A - ?B - ?C) \<union> ?D") by (simp add:V)
+ moreover from ih have ac: "finite (?A - ?B - ?C)" by simp
+ moreover have "finite ?D"
+ proof -
+ have "?D = {} \<or> (\<exists> a. ?D = {a})"
+ by (unfold next_th_def, auto)
+ thus ?thesis
+ proof
+ assume h: "?D = {}"
+ show ?thesis by (unfold h, simp)
+ next
+ assume "\<exists> a. ?D = {a}"
+ thus ?thesis
+ by (metis finite.simps)
+ qed
+ qed
+ ultimately show ?thesis by simp
+ next
+ case (P th cs)
+ from P vt stp have vtt: "vt (P th cs#s)" by auto
+ from step_RAG_p [OF this] P
+ have "RAG (e # s) =
+ (if wq s cs = [] then RAG s \<union> {(Cs cs, Th th)} else
+ RAG s \<union> {(Th th, Cs cs)})" (is "?L = ?R")
+ by simp
+ moreover have "finite ?R"
+ proof(cases "wq s cs = []")
+ case True
+ hence eq_r: "?R = RAG s \<union> {(Cs cs, Th th)}" by simp
+ with True and ih show ?thesis by auto
+ next
+ case False
+ hence "?R = RAG s \<union> {(Th th, Cs cs)}" by simp
+ with False and ih show ?thesis by auto
+ qed
+ ultimately show ?thesis by auto
+ next
+ case (Set thread prio)
+ with ih
+ show ?thesis by (simp add:RAG_set_unchanged)
+ qed
+ next
+ case vt_nil
+ show "finite (RAG ([]::state))"
+ by (auto simp: s_RAG_def cs_waiting_def
+ cs_holding_def wq_def acyclic_def)
+ qed
+qed
+
+text {* Several useful lemmas *}
+
+lemma wf_dep_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
+
+end
+
+lemma hd_np_in: "x \<in> set l \<Longrightarrow> hd l \<in> set l"
+ by (induct l, auto)
+
+lemma th_chasing: "(Th th, Cs cs) \<in> RAG (s::state) \<Longrightarrow> \<exists> th'. (Cs cs, Th th') \<in> RAG s"
+ by (auto simp:s_RAG_def s_holding_def cs_holding_def cs_waiting_def wq_def dest:hd_np_in)
+
+context valid_trace
+begin
+
+lemma wq_threads:
+ assumes h: "th \<in> set (wq s cs)"
+ shows "th \<in> threads s"
+proof -
+ from vt and h show ?thesis
+ proof(induct arbitrary: th cs)
+ case (vt_cons s e)
+ interpret vt_s: valid_trace s
+ using vt_cons(1) by (unfold_locales, auto)
+ assume ih: "\<And>th cs. th \<in> set (wq s cs) \<Longrightarrow> th \<in> threads s"
+ and stp: "step s e"
+ and vt: "vt s"
+ and h: "th \<in> set (wq (e # s) cs)"
+ show ?case
+ proof(cases e)
+ case (Create th' prio)
+ with ih h show ?thesis
+ by (auto simp:wq_def Let_def)
+ next
+ case (Exit th')
+ with stp ih h show ?thesis
+ apply (auto simp:wq_def Let_def)
+ apply (ind_cases "step s (Exit th')")
+ apply (auto simp:runing_def readys_def s_holding_def s_waiting_def holdents_def
+ s_RAG_def s_holding_def cs_holding_def)
+ done
+ next
+ case (V th' cs')
+ show ?thesis
+ proof(cases "cs' = cs")
+ case False
+ with h
+ show ?thesis
+ apply(unfold wq_def V, auto simp:Let_def V split:prod.splits, fold wq_def)
+ by (drule_tac ih, simp)
+ next
+ case True
+ from h
+ show ?thesis
+ proof(unfold V wq_def)
+ assume th_in: "th \<in> set (wq_fun (schs (V th' cs' # s)) cs)" (is "th \<in> set ?l")
+ show "th \<in> threads (V th' cs' # s)"
+ proof(cases "cs = cs'")
+ case False
+ hence "?l = wq_fun (schs s) cs" by (simp add:Let_def)
+ with th_in have " th \<in> set (wq s cs)"
+ by (fold wq_def, simp)
+ from ih [OF this] show ?thesis by simp
+ next
+ case True
+ show ?thesis
+ proof(cases "wq_fun (schs s) cs'")
+ case Nil
+ with h V show ?thesis
+ apply (auto simp:wq_def Let_def split:if_splits)
+ by (fold wq_def, drule_tac ih, simp)
+ next
+ case (Cons a rest)
+ assume eq_wq: "wq_fun (schs s) cs' = a # rest"
+ with h V show ?thesis
+ apply (auto simp:Let_def wq_def split:if_splits)
+ proof -
+ assume th_in: "th \<in> set (SOME q. distinct q \<and> set q = set rest)"
+ have "set (SOME q. distinct q \<and> set q = set rest) = set rest"
+ proof(rule someI2)
+ from vt_s.wq_distinct[of cs'] and eq_wq[folded wq_def]
+ show "distinct rest \<and> set rest = set rest" by auto
+ next
+ show "\<And>x. distinct x \<and> set x = set rest \<Longrightarrow> set x = set rest"
+ by auto
+ qed
+ with eq_wq th_in have "th \<in> set (wq_fun (schs s) cs')" by auto
+ from ih[OF this[folded wq_def]] show "th \<in> threads s" .
+ next
+ assume th_in: "th \<in> set (wq_fun (schs s) cs)"
+ from ih[OF this[folded wq_def]]
+ show "th \<in> threads s" .
+ qed
+ qed
+ qed
+ qed
+ qed
+ next
+ case (P th' cs')
+ from h stp
+ show ?thesis
+ apply (unfold P wq_def)
+ apply (auto simp:Let_def split:if_splits, fold wq_def)
+ apply (auto intro:ih)
+ apply(ind_cases "step s (P th' cs')")
+ by (unfold runing_def readys_def, auto)
+ next
+ case (Set thread prio)
+ with ih h show ?thesis
+ by (auto simp:wq_def Let_def)
+ qed
+ next
+ case vt_nil
+ thus ?case by (auto simp:wq_def)
+ qed
+qed
+
+lemma range_in: "\<lbrakk>(Th th) \<in> Range (RAG (s::state))\<rbrakk> \<Longrightarrow> th \<in> threads s"
+ apply(unfold s_RAG_def cs_waiting_def cs_holding_def)
+ by (auto intro:wq_threads)
+
+lemma readys_v_eq:
+ assumes neq_th: "th \<noteq> thread"
+ and eq_wq: "wq s cs = thread#rest"
+ and not_in: "th \<notin> set rest"
+ shows "(th \<in> readys (V thread cs#s)) = (th \<in> readys s)"
+proof -
+ from assms show ?thesis
+ apply (auto simp:readys_def)
+ apply(simp add:s_waiting_def[folded wq_def])
+ apply (erule_tac x = csa in allE)
+ apply (simp add:s_waiting_def wq_def Let_def split:if_splits)
+ apply (case_tac "csa = cs", simp)
+ apply (erule_tac x = cs in allE)
+ apply(auto simp add: s_waiting_def[folded wq_def] Let_def split: list.splits)
+ apply(auto simp add: wq_def)
+ apply (auto simp:s_waiting_def wq_def Let_def split:list.splits)
+ proof -
+ assume th_nin: "th \<notin> set rest"
+ and th_in: "th \<in> set (SOME q. distinct q \<and> set q = set rest)"
+ and eq_wq: "wq_fun (schs s) cs = thread # rest"
+ have "set (SOME q. distinct q \<and> set q = set rest) = set rest"
+ proof(rule someI2)
+ from wq_distinct[of cs, unfolded wq_def] and eq_wq[unfolded wq_def]
+ show "distinct rest \<and> set rest = set rest" by auto
+ next
+ show "\<And>x. distinct x \<and> set x = set rest \<Longrightarrow> set x = set rest" by auto
+ qed
+ with th_nin th_in show False by auto
+ qed
+qed
+
+text {* \noindent
+ The following lemmas shows that: starting from any node in @{text "RAG"},
+ by chasing out-going edges, it is always possible to reach a node representing a ready
+ thread. In this lemma, it is the @{text "th'"}.
+*}
+
+lemma chain_building:
+ shows "node \<in> Domain (RAG s) \<longrightarrow> (\<exists> th'. th' \<in> readys s \<and> (node, Th th') \<in> (RAG s)^+)"
+proof -
+ from wf_dep_converse
+ have h: "wf ((RAG s)\<inverse>)" .
+ show ?thesis
+ proof(induct rule:wf_induct [OF h])
+ fix x
+ assume ih [rule_format]:
+ "\<forall>y. (y, x) \<in> (RAG s)\<inverse> \<longrightarrow>
+ y \<in> Domain (RAG s) \<longrightarrow> (\<exists>th'. th' \<in> readys s \<and> (y, Th th') \<in> (RAG s)\<^sup>+)"
+ show "x \<in> Domain (RAG s) \<longrightarrow> (\<exists>th'. th' \<in> readys s \<and> (x, Th th') \<in> (RAG s)\<^sup>+)"
+ proof
+ assume x_d: "x \<in> Domain (RAG s)"
+ show "\<exists>th'. th' \<in> readys s \<and> (x, Th th') \<in> (RAG s)\<^sup>+"
+ proof(cases x)
+ case (Th th)
+ from x_d Th obtain cs where x_in: "(Th th, Cs cs) \<in> RAG s" by (auto simp:s_RAG_def)
+ with Th have x_in_r: "(Cs cs, x) \<in> (RAG s)^-1" by simp
+ from th_chasing [OF x_in] obtain th' where "(Cs cs, Th th') \<in> RAG s" by blast
+ hence "Cs cs \<in> Domain (RAG s)" by auto
+ from ih [OF x_in_r this] obtain th'
+ where th'_ready: " th' \<in> readys s" and cs_in: "(Cs cs, Th th') \<in> (RAG s)\<^sup>+" by auto
+ have "(x, Th th') \<in> (RAG s)\<^sup>+" using Th x_in cs_in by auto
+ with th'_ready show ?thesis by auto
+ next
+ case (Cs cs)
+ from x_d Cs obtain th' where th'_d: "(Th th', x) \<in> (RAG s)^-1" by (auto simp:s_RAG_def)
+ show ?thesis
+ proof(cases "th' \<in> readys s")
+ case True
+ from True and th'_d show ?thesis by auto
+ next
+ case False
+ from th'_d and range_in have "th' \<in> threads s" by auto
+ with False have "Th th' \<in> Domain (RAG s)"
+ by (auto simp:readys_def wq_def s_waiting_def s_RAG_def cs_waiting_def Domain_def)
+ from ih [OF th'_d this]
+ obtain th'' where
+ th''_r: "th'' \<in> readys s" and
+ th''_in: "(Th th', Th th'') \<in> (RAG s)\<^sup>+" by auto
+ from th'_d and th''_in
+ have "(x, Th th'') \<in> (RAG s)\<^sup>+" by auto
+ with th''_r show ?thesis by auto
+ qed
+ qed
+ qed
+ qed
+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 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 holding_unique: "\<lbrakk>holding (s::state) th1 cs; holding s th2 cs\<rbrakk> \<Longrightarrow> th1 = th2"
+ by (unfold s_holding_def cs_holding_def, auto)
+
+context valid_trace
+begin
+
+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 holding_unique)
+
+end
+
+
+lemma trancl_split: "(a, b) \<in> r^+ \<Longrightarrow> \<exists> c. (a, c) \<in> r"
+by (induct rule:trancl_induct, auto)
+
+context valid_trace
begin
-text {* @{text "the_preced"} is also the same as @{text "preced"}, the only
- difference is the order of arguemts. *}
-definition "the_preced s th = preced th s"
+lemma dchain_unique:
+ assumes th1_d: "(n, Th th1) \<in> (RAG s)^+"
+ and th1_r: "th1 \<in> readys s"
+ and th2_d: "(n, Th th2) \<in> (RAG s)^+"
+ and th2_r: "th2 \<in> readys s"
+ shows "th1 = th2"
+proof -
+ { assume neq: "th1 \<noteq> th2"
+ hence "Th th1 \<noteq> Th th2" by simp
+ from unique_chain [OF _ th1_d th2_d this] and unique_RAG
+ have "(Th th1, Th th2) \<in> (RAG s)\<^sup>+ \<or> (Th th2, Th th1) \<in> (RAG s)\<^sup>+" by auto
+ hence "False"
+ proof
+ assume "(Th th1, Th th2) \<in> (RAG s)\<^sup>+"
+ from trancl_split [OF this]
+ obtain n where dd: "(Th th1, n) \<in> RAG s" by auto
+ then obtain cs where eq_n: "n = Cs cs"
+ by (auto simp:s_RAG_def s_holding_def cs_holding_def cs_waiting_def wq_def dest:hd_np_in)
+ from dd eq_n have "th1 \<notin> readys s"
+ by (auto simp:readys_def s_RAG_def wq_def s_waiting_def cs_waiting_def)
+ with th1_r show ?thesis by auto
+ next
+ assume "(Th th2, Th th1) \<in> (RAG s)\<^sup>+"
+ from trancl_split [OF this]
+ obtain n where dd: "(Th th2, n) \<in> RAG s" by auto
+ then obtain cs where eq_n: "n = Cs cs"
+ by (auto simp:s_RAG_def s_holding_def cs_holding_def cs_waiting_def wq_def dest:hd_np_in)
+ from dd eq_n have "th2 \<notin> readys s"
+ by (auto simp:readys_def wq_def s_RAG_def s_waiting_def cs_waiting_def)
+ with th2_r show ?thesis by auto
+ qed
+ } thus ?thesis by auto
+qed
+
+end
+
+
+lemma step_holdents_p_add:
+ assumes vt: "vt (P th cs#s)"
+ and "wq s cs = []"
+ shows "holdents (P th cs#s) th = holdents s th \<union> {cs}"
+proof -
+ from assms show ?thesis
+ unfolding holdents_test step_RAG_p[OF vt] by (auto)
+qed
+
+lemma step_holdents_p_eq:
+ assumes vt: "vt (P th cs#s)"
+ and "wq s cs \<noteq> []"
+ shows "holdents (P th cs#s) th = holdents s th"
+proof -
+ from assms show ?thesis
+ unfolding holdents_test step_RAG_p[OF vt] by auto
+qed
+
+
+lemma (in valid_trace) finite_holding :
+ shows "finite (holdents s th)"
+proof -
+ let ?F = "\<lambda> (x, y). the_cs x"
+ from finite_RAG
+ have "finite (RAG s)" .
+ hence "finite (?F `(RAG s))" by simp
+ moreover have "{cs . (Cs cs, Th th) \<in> RAG s} \<subseteq> \<dots>"
+ proof -
+ { have h: "\<And> a A f. a \<in> A \<Longrightarrow> f a \<in> f ` A" by auto
+ fix x assume "(Cs x, Th th) \<in> RAG s"
+ hence "?F (Cs x, Th th) \<in> ?F `(RAG s)" by (rule h)
+ moreover have "?F (Cs x, Th th) = x" by simp
+ ultimately have "x \<in> (\<lambda>(x, y). the_cs x) ` RAG s" by simp
+ } thus ?thesis by auto
+ qed
+ ultimately show ?thesis by (unfold holdents_test, auto intro:finite_subset)
+qed
+
+lemma cntCS_v_dec:
+ assumes vtv: "vt (V thread cs#s)"
+ shows "(cntCS (V thread cs#s) thread + 1) = cntCS s thread"
+proof -
+ from vtv interpret vt_s: valid_trace s
+ by (cases, unfold_locales, simp)
+ from vtv interpret vt_v: valid_trace "V thread cs#s"
+ by (unfold_locales, simp)
+ from step_back_step[OF vtv]
+ have cs_in: "cs \<in> holdents s thread"
+ apply (cases, unfold holdents_test s_RAG_def, simp)
+ by (unfold cs_holding_def s_holding_def wq_def, auto)
+ moreover have cs_not_in:
+ "(holdents (V thread cs#s) thread) = holdents s thread - {cs}"
+ apply (insert vt_s.wq_distinct[of cs])
+ apply (unfold holdents_test, unfold step_RAG_v[OF vtv],
+ auto simp:next_th_def)
+ proof -
+ fix rest
+ assume dst: "distinct (rest::thread list)"
+ and ne: "rest \<noteq> []"
+ and hd_ni: "hd (SOME q. distinct q \<and> set q = set rest) \<notin> set rest"
+ moreover have "set (SOME q. distinct q \<and> set q = set rest) = set rest"
+ proof(rule someI2)
+ from dst show "distinct rest \<and> set rest = set rest" by auto
+ next
+ show "\<And>x. distinct x \<and> set x = set rest \<Longrightarrow> set x = set rest" by auto
+ qed
+ ultimately have "hd (SOME q. distinct q \<and> set q = set rest) \<notin>
+ set (SOME q. distinct q \<and> set q = set rest)" by simp
+ moreover have "(SOME q. distinct q \<and> set q = set rest) \<noteq> []"
+ proof(rule someI2)
+ from dst show "distinct rest \<and> set rest = set rest" by auto
+ next
+ fix x assume " distinct x \<and> set x = set rest" with ne
+ show "x \<noteq> []" by auto
+ qed
+ ultimately
+ show "(Cs cs, Th (hd (SOME q. distinct q \<and> set q = set rest))) \<in> RAG s"
+ by auto
+ next
+ fix rest
+ assume dst: "distinct (rest::thread list)"
+ and ne: "rest \<noteq> []"
+ and hd_ni: "hd (SOME q. distinct q \<and> set q = set rest) \<notin> set rest"
+ moreover have "set (SOME q. distinct q \<and> set q = set rest) = set rest"
+ proof(rule someI2)
+ from dst show "distinct rest \<and> set rest = set rest" by auto
+ next
+ show "\<And>x. distinct x \<and> set x = set rest \<Longrightarrow> set x = set rest" by auto
+ qed
+ ultimately have "hd (SOME q. distinct q \<and> set q = set rest) \<notin>
+ set (SOME q. distinct q \<and> set q = set rest)" by simp
+ moreover have "(SOME q. distinct q \<and> set q = set rest) \<noteq> []"
+ proof(rule someI2)
+ from dst show "distinct rest \<and> set rest = set rest" by auto
+ next
+ fix x assume " distinct x \<and> set x = set rest" with ne
+ show "x \<noteq> []" by auto
+ qed
+ ultimately show "False" by auto
+ qed
+ ultimately
+ have "holdents s thread = insert cs (holdents (V thread cs#s) thread)"
+ by auto
+ moreover have "card \<dots> =
+ Suc (card ((holdents (V thread cs#s) thread) - {cs}))"
+ proof(rule card_insert)
+ from vt_v.finite_holding
+ show " finite (holdents (V thread cs # s) thread)" .
+ qed
+ moreover from cs_not_in
+ have "cs \<notin> (holdents (V thread cs#s) thread)" by auto
+ ultimately show ?thesis by (simp add:cntCS_def)
+qed
+
+lemma 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_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)
+
+context valid_trace
+begin
+
+text {* (* ddd *) \noindent
+ The relationship between @{text "cntP"}, @{text "cntV"} and @{text "cntCS"}
+ of one particular thread.
+*}
+
+lemma cnp_cnv_cncs:
+ shows "cntP s th = cntV s th + (if (th \<in> readys s \<or> th \<notin> threads s)
+ then cntCS s th else cntCS s th + 1)"
+proof -
+ from vt show ?thesis
+ proof(induct arbitrary:th)
+ case (vt_cons s e)
+ interpret vt_s: valid_trace s using vt_cons(1) by (unfold_locales, simp)
+ assume vt: "vt s"
+ and ih: "\<And>th. cntP s th = cntV s th +
+ (if (th \<in> readys s \<or> th \<notin> threads s) then cntCS s th else cntCS s th + 1)"
+ and stp: "step s e"
+ from stp show ?case
+ proof(cases)
+ case (thread_create thread prio)
+ assume eq_e: "e = Create thread prio"
+ and not_in: "thread \<notin> threads s"
+ show ?thesis
+ proof -
+ { fix cs
+ assume "thread \<in> set (wq s cs)"
+ from vt_s.wq_threads [OF this] have "thread \<in> threads s" .
+ with not_in have "False" by simp
+ } with eq_e have eq_readys: "readys (e#s) = readys s \<union> {thread}"
+ by (auto simp:readys_def threads.simps s_waiting_def
+ wq_def cs_waiting_def Let_def)
+ from eq_e have eq_cnp: "cntP (e#s) th = cntP s th" by (simp add:cntP_def count_def)
+ from eq_e have eq_cnv: "cntV (e#s) th = cntV s th" by (simp add:cntV_def count_def)
+ have eq_cncs: "cntCS (e#s) th = cntCS s th"
+ unfolding cntCS_def holdents_test
+ by (simp add:RAG_create_unchanged eq_e)
+ { assume "th \<noteq> thread"
+ with eq_readys eq_e
+ have "(th \<in> readys (e # s) \<or> th \<notin> threads (e # s)) =
+ (th \<in> readys (s) \<or> th \<notin> threads (s))"
+ by (simp add:threads.simps)
+ with eq_cnp eq_cnv eq_cncs ih not_in
+ have ?thesis by simp
+ } moreover {
+ assume eq_th: "th = thread"
+ with not_in ih have " cntP s th = cntV s th + cntCS s th" by simp
+ moreover from eq_th and eq_readys have "th \<in> readys (e#s)" by simp
+ moreover note eq_cnp eq_cnv eq_cncs
+ ultimately have ?thesis by auto
+ } ultimately show ?thesis by blast
+ qed
+ next
+ case (thread_exit thread)
+ assume eq_e: "e = Exit thread"
+ and is_runing: "thread \<in> runing s"
+ and no_hold: "holdents s thread = {}"
+ from eq_e have eq_cnp: "cntP (e#s) th = cntP s th" by (simp add:cntP_def count_def)
+ from eq_e have eq_cnv: "cntV (e#s) th = cntV s th" by (simp add:cntV_def count_def)
+ have eq_cncs: "cntCS (e#s) th = cntCS s th"
+ unfolding cntCS_def holdents_test
+ by (simp add:RAG_exit_unchanged eq_e)
+ { assume "th \<noteq> thread"
+ with eq_e
+ have "(th \<in> readys (e # s) \<or> th \<notin> threads (e # s)) =
+ (th \<in> readys (s) \<or> th \<notin> threads (s))"
+ apply (simp add:threads.simps readys_def)
+ apply (subst s_waiting_def)
+ apply (simp add:Let_def)
+ apply (subst s_waiting_def, simp)
+ done
+ with eq_cnp eq_cnv eq_cncs ih
+ have ?thesis by simp
+ } moreover {
+ assume eq_th: "th = thread"
+ with ih is_runing have " cntP s th = cntV s th + cntCS s th"
+ by (simp add:runing_def)
+ moreover from eq_th eq_e have "th \<notin> threads (e#s)"
+ by simp
+ moreover note eq_cnp eq_cnv eq_cncs
+ ultimately have ?thesis by auto
+ } ultimately show ?thesis by blast
+ next
+ case (thread_P thread cs)
+ assume eq_e: "e = P thread cs"
+ and is_runing: "thread \<in> runing s"
+ and no_dep: "(Cs cs, Th thread) \<notin> (RAG s)\<^sup>+"
+ from thread_P vt stp ih have vtp: "vt (P thread cs#s)" by auto
+ then interpret vt_p: valid_trace "(P thread cs#s)"
+ by (unfold_locales, simp)
+ show ?thesis
+ proof -
+ { have hh: "\<And> A B C. (B = C) \<Longrightarrow> (A \<and> B) = (A \<and> C)" by blast
+ assume neq_th: "th \<noteq> thread"
+ with eq_e
+ have eq_readys: "(th \<in> readys (e#s)) = (th \<in> readys (s))"
+ apply (simp add:readys_def s_waiting_def wq_def Let_def)
+ apply (rule_tac hh)
+ apply (intro iffI allI, clarify)
+ apply (erule_tac x = csa in allE, auto)
+ apply (subgoal_tac "wq_fun (schs s) cs \<noteq> []", auto)
+ apply (erule_tac x = cs in allE, auto)
+ by (case_tac "(wq_fun (schs s) cs)", auto)
+ moreover from neq_th eq_e have "cntCS (e # s) th = cntCS s th"
+ apply (simp add:cntCS_def holdents_test)
+ by (unfold step_RAG_p [OF vtp], auto)
+ moreover from eq_e neq_th have "cntP (e # s) th = cntP s th"
+ by (simp add:cntP_def count_def)
+ moreover from eq_e neq_th have "cntV (e#s) th = cntV s th"
+ by (simp add:cntV_def count_def)
+ moreover from eq_e neq_th have "threads (e#s) = threads s" by simp
+ moreover note ih [of th]
+ ultimately have ?thesis by simp
+ } moreover {
+ assume eq_th: "th = thread"
+ have ?thesis
+ proof -
+ from eq_e eq_th have eq_cnp: "cntP (e # s) th = 1 + (cntP s th)"
+ by (simp add:cntP_def count_def)
+ from eq_e eq_th have eq_cnv: "cntV (e#s) th = cntV s th"
+ by (simp add:cntV_def count_def)
+ show ?thesis
+ proof (cases "wq s cs = []")
+ case True
+ with is_runing
+ have "th \<in> readys (e#s)"
+ apply (unfold eq_e wq_def, unfold readys_def s_RAG_def)
+ apply (simp add: wq_def[symmetric] runing_def eq_th s_waiting_def)
+ by (auto simp:readys_def wq_def Let_def s_waiting_def wq_def)
+ moreover have "cntCS (e # s) th = 1 + cntCS s th"
+ proof -
+ have "card {csa. csa = cs \<or> (Cs csa, Th thread) \<in> RAG s} =
+ Suc (card {cs. (Cs cs, Th thread) \<in> RAG s})" (is "card ?L = Suc (card ?R)")
+ proof -
+ have "?L = insert cs ?R" by auto
+ moreover have "card \<dots> = Suc (card (?R - {cs}))"
+ proof(rule card_insert)
+ from vt_s.finite_holding [of thread]
+ show " finite {cs. (Cs cs, Th thread) \<in> RAG s}"
+ by (unfold holdents_test, simp)
+ qed
+ moreover have "?R - {cs} = ?R"
+ proof -
+ have "cs \<notin> ?R"
+ proof
+ assume "cs \<in> {cs. (Cs cs, Th thread) \<in> RAG s}"
+ with no_dep show False by auto
+ qed
+ thus ?thesis by auto
+ qed
+ ultimately show ?thesis by auto
+ qed
+ thus ?thesis
+ apply (unfold eq_e eq_th cntCS_def)
+ apply (simp add: holdents_test)
+ by (unfold step_RAG_p [OF vtp], auto simp:True)
+ qed
+ moreover from is_runing have "th \<in> readys s"
+ by (simp add:runing_def eq_th)
+ moreover note eq_cnp eq_cnv ih [of th]
+ ultimately show ?thesis by auto
+ next
+ case False
+ have eq_wq: "wq (e#s) cs = wq s cs @ [th]"
+ by (unfold eq_th eq_e wq_def, auto simp:Let_def)
+ have "th \<notin> readys (e#s)"
+ proof
+ assume "th \<in> readys (e#s)"
+ hence "\<forall>cs. \<not> waiting (e # s) th cs" by (simp add:readys_def)
+ from this[rule_format, of cs] have " \<not> waiting (e # s) th cs" .
+ hence "th \<in> set (wq (e#s) cs) \<Longrightarrow> th = hd (wq (e#s) cs)"
+ by (simp add:s_waiting_def wq_def)
+ moreover from eq_wq have "th \<in> set (wq (e#s) cs)" by auto
+ ultimately have "th = hd (wq (e#s) cs)" by blast
+ with eq_wq have "th = hd (wq s cs @ [th])" by simp
+ hence "th = hd (wq s cs)" using False by auto
+ with False eq_wq vt_p.wq_distinct [of cs]
+ show False by (fold eq_e, auto)
+ qed
+ moreover from is_runing have "th \<in> threads (e#s)"
+ by (unfold eq_e, auto simp:runing_def readys_def eq_th)
+ moreover have "cntCS (e # s) th = cntCS s th"
+ apply (unfold cntCS_def holdents_test eq_e step_RAG_p[OF vtp])
+ by (auto simp:False)
+ moreover note eq_cnp eq_cnv ih[of th]
+ moreover from is_runing have "th \<in> readys s"
+ by (simp add:runing_def eq_th)
+ ultimately show ?thesis by auto
+ qed
+ qed
+ } ultimately show ?thesis by blast
+ qed
+ next
+ case (thread_V thread cs)
+ from assms vt stp ih thread_V have vtv: "vt (V thread cs # s)" by auto
+ then interpret vt_v: valid_trace "(V thread cs # s)" by (unfold_locales, simp)
+ assume eq_e: "e = V thread cs"
+ and is_runing: "thread \<in> runing s"
+ and hold: "holding s thread cs"
+ from hold obtain rest
+ where eq_wq: "wq s cs = thread # rest"
+ by (case_tac "wq s cs", auto simp: wq_def s_holding_def)
+ have eq_threads: "threads (e#s) = threads s" by (simp add: eq_e)
+ have eq_set: "set (SOME q. distinct q \<and> set q = set rest) = set rest"
+ proof(rule someI2)
+ from vt_v.wq_distinct[of cs] and eq_wq
+ show "distinct rest \<and> set rest = set rest"
+ by (metis distinct.simps(2) vt_s.wq_distinct)
+ next
+ show "\<And>x. distinct x \<and> set x = set rest \<Longrightarrow> set x = set rest"
+ by auto
+ qed
+ show ?thesis
+ proof -
+ { assume eq_th: "th = thread"
+ from eq_th have eq_cnp: "cntP (e # s) th = cntP s th"
+ by (unfold eq_e, simp add:cntP_def count_def)
+ moreover from eq_th have eq_cnv: "cntV (e#s) th = 1 + cntV s th"
+ by (unfold eq_e, simp add:cntV_def count_def)
+ moreover from cntCS_v_dec [OF vtv]
+ have "cntCS (e # s) thread + 1 = cntCS s thread"
+ by (simp add:eq_e)
+ moreover from is_runing have rd_before: "thread \<in> readys s"
+ by (unfold runing_def, simp)
+ moreover have "thread \<in> readys (e # s)"
+ proof -
+ from is_runing
+ have "thread \<in> threads (e#s)"
+ by (unfold eq_e, auto simp:runing_def readys_def)
+ moreover have "\<forall> cs1. \<not> waiting (e#s) thread cs1"
+ proof
+ fix cs1
+ { assume eq_cs: "cs1 = cs"
+ have "\<not> waiting (e # s) thread cs1"
+ proof -
+ from eq_wq
+ have "thread \<notin> set (wq (e#s) cs1)"
+ apply(unfold eq_e wq_def eq_cs s_holding_def)
+ apply (auto simp:Let_def)
+ proof -
+ assume "thread \<in> set (SOME q. distinct q \<and> set q = set rest)"
+ with eq_set have "thread \<in> set rest" by simp
+ with vt_v.wq_distinct[of cs]
+ and eq_wq show False
+ by (metis distinct.simps(2) vt_s.wq_distinct)
+ qed
+ thus ?thesis by (simp add:wq_def s_waiting_def)
+ qed
+ } moreover {
+ assume neq_cs: "cs1 \<noteq> cs"
+ have "\<not> waiting (e # s) thread cs1"
+ proof -
+ from wq_v_neq [OF neq_cs[symmetric]]
+ have "wq (V thread cs # s) cs1 = wq s cs1" .
+ moreover have "\<not> waiting s thread cs1"
+ proof -
+ from runing_ready and is_runing
+ have "thread \<in> readys s" by auto
+ thus ?thesis by (simp add:readys_def)
+ qed
+ ultimately show ?thesis
+ by (auto simp:wq_def s_waiting_def eq_e)
+ qed
+ } ultimately show "\<not> waiting (e # s) thread cs1" by blast
+ qed
+ ultimately show ?thesis by (simp add:readys_def)
+ qed
+ moreover note eq_th ih
+ ultimately have ?thesis by auto
+ } moreover {
+ assume neq_th: "th \<noteq> thread"
+ from neq_th eq_e have eq_cnp: "cntP (e # s) th = cntP s th"
+ by (simp add:cntP_def count_def)
+ from neq_th eq_e have eq_cnv: "cntV (e # s) th = cntV s th"
+ by (simp add:cntV_def count_def)
+ have ?thesis
+ proof(cases "th \<in> set rest")
+ case False
+ have "(th \<in> readys (e # s)) = (th \<in> readys s)"
+ apply (insert step_back_vt[OF vtv])
+ by (simp add: False eq_e eq_wq neq_th vt_s.readys_v_eq)
+ moreover have "cntCS (e#s) th = cntCS s th"
+ apply (insert neq_th, unfold eq_e cntCS_def holdents_test step_RAG_v[OF vtv], auto)
+ proof -
+ have "{csa. (Cs csa, Th th) \<in> RAG s \<or> csa = cs \<and> next_th s thread cs th} =
+ {cs. (Cs cs, Th th) \<in> RAG s}"
+ proof -
+ from False eq_wq
+ have " next_th s thread cs th \<Longrightarrow> (Cs cs, Th th) \<in> RAG s"
+ apply (unfold next_th_def, auto)
+ proof -
+ assume ne: "rest \<noteq> []"
+ and ni: "hd (SOME q. distinct q \<and> set q = set rest) \<notin> set rest"
+ and eq_wq: "wq s cs = thread # rest"
+ from eq_set ni have "hd (SOME q. distinct q \<and> set q = set rest) \<notin>
+ set (SOME q. distinct q \<and> set q = set rest)
+ " by simp
+ moreover have "(SOME q. distinct q \<and> set q = set rest) \<noteq> []"
+ proof(rule someI2)
+ from vt_s.wq_distinct[ of cs] and eq_wq
+ show "distinct rest \<and> set rest = set rest" by auto
+ next
+ fix x assume "distinct x \<and> set x = set rest"
+ with ne show "x \<noteq> []" by auto
+ qed
+ ultimately show
+ "(Cs cs, Th (hd (SOME q. distinct q \<and> set q = set rest))) \<in> RAG s"
+ by auto
+ qed
+ thus ?thesis by auto
+ qed
+ thus "card {csa. (Cs csa, Th th) \<in> RAG s \<or> csa = cs \<and> next_th s thread cs th} =
+ card {cs. (Cs cs, Th th) \<in> RAG s}" by simp
+ qed
+ moreover note ih eq_cnp eq_cnv eq_threads
+ ultimately show ?thesis by auto
+ next
+ case True
+ assume th_in: "th \<in> set rest"
+ show ?thesis
+ proof(cases "next_th s thread cs th")
+ case False
+ with eq_wq and th_in have
+ neq_hd: "th \<noteq> hd (SOME q. distinct q \<and> set q = set rest)" (is "th \<noteq> hd ?rest")
+ by (auto simp:next_th_def)
+ have "(th \<in> readys (e # s)) = (th \<in> readys s)"
+ proof -
+ from eq_wq and th_in
+ have "\<not> th \<in> readys s"
+ apply (auto simp:readys_def s_waiting_def)
+ apply (rule_tac x = cs in exI, auto)
+ by (insert vt_s.wq_distinct[of cs], auto simp add: wq_def)
+ moreover
+ from eq_wq and th_in and neq_hd
+ have "\<not> (th \<in> readys (e # s))"
+ apply (auto simp:readys_def s_waiting_def eq_e wq_def Let_def split:list.splits)
+ by (rule_tac x = cs in exI, auto simp:eq_set)
+ ultimately show ?thesis by auto
+ qed
+ moreover have "cntCS (e#s) th = cntCS s th"
+ proof -
+ from eq_wq and th_in and neq_hd
+ have "(holdents (e # s) th) = (holdents s th)"
+ apply (unfold eq_e step_RAG_v[OF vtv],
+ auto simp:next_th_def eq_set s_RAG_def holdents_test wq_def
+ Let_def cs_holding_def)
+ by (insert vt_s.wq_distinct[of cs], auto simp:wq_def)
+ thus ?thesis by (simp add:cntCS_def)
+ qed
+ moreover note ih eq_cnp eq_cnv eq_threads
+ ultimately show ?thesis by auto
+ next
+ case True
+ let ?rest = " (SOME q. distinct q \<and> set q = set rest)"
+ let ?t = "hd ?rest"
+ from True eq_wq th_in neq_th
+ have "th \<in> readys (e # s)"
+ apply (auto simp:eq_e readys_def s_waiting_def wq_def
+ Let_def next_th_def)
+ proof -
+ assume eq_wq: "wq_fun (schs s) cs = thread # rest"
+ and t_in: "?t \<in> set rest"
+ show "?t \<in> threads s"
+ proof(rule vt_s.wq_threads)
+ from eq_wq and t_in
+ show "?t \<in> set (wq s cs)" by (auto simp:wq_def)
+ qed
+ next
+ fix csa
+ assume eq_wq: "wq_fun (schs s) cs = thread # rest"
+ and t_in: "?t \<in> set rest"
+ and neq_cs: "csa \<noteq> cs"
+ and t_in': "?t \<in> set (wq_fun (schs s) csa)"
+ show "?t = hd (wq_fun (schs s) csa)"
+ proof -
+ { assume neq_hd': "?t \<noteq> hd (wq_fun (schs s) csa)"
+ from vt_s.wq_distinct[of cs] and
+ eq_wq[folded wq_def] and t_in eq_wq
+ have "?t \<noteq> thread" by auto
+ with eq_wq and t_in
+ have w1: "waiting s ?t cs"
+ by (auto simp:s_waiting_def wq_def)
+ from t_in' neq_hd'
+ have w2: "waiting s ?t csa"
+ by (auto simp:s_waiting_def wq_def)
+ from vt_s.waiting_unique[OF w1 w2]
+ and neq_cs have "False" by auto
+ } thus ?thesis by auto
+ qed
+ qed
+ moreover have "cntP s th = cntV s th + cntCS s th + 1"
+ proof -
+ have "th \<notin> readys s"
+ proof -
+ from True eq_wq neq_th th_in
+ show ?thesis
+ apply (unfold readys_def s_waiting_def, auto)
+ by (rule_tac x = cs in exI, auto simp add: wq_def)
+ qed
+ moreover have "th \<in> threads s"
+ proof -
+ from th_in eq_wq
+ have "th \<in> set (wq s cs)" by simp
+ from vt_s.wq_threads [OF this]
+ show ?thesis .
+ qed
+ ultimately show ?thesis using ih by auto
+ qed
+ moreover from True neq_th have "cntCS (e # s) th = 1 + cntCS s th"
+ apply (unfold cntCS_def holdents_test eq_e step_RAG_v[OF vtv], auto)
+ proof -
+ show "card {csa. (Cs csa, Th th) \<in> RAG s \<or> csa = cs} =
+ Suc (card {cs. (Cs cs, Th th) \<in> RAG s})"
+ (is "card ?A = Suc (card ?B)")
+ proof -
+ have "?A = insert cs ?B" by auto
+ hence "card ?A = card (insert cs ?B)" by simp
+ also have "\<dots> = Suc (card ?B)"
+ proof(rule card_insert_disjoint)
+ have "?B \<subseteq> ((\<lambda> (x, y). the_cs x) ` RAG s)"
+ apply (auto simp:image_def)
+ by (rule_tac x = "(Cs x, Th th)" in bexI, auto)
+ with vt_s.finite_RAG
+ show "finite {cs. (Cs cs, Th th) \<in> RAG s}" by (auto intro:finite_subset)
+ next
+ show "cs \<notin> {cs. (Cs cs, Th th) \<in> RAG s}"
+ proof
+ assume "cs \<in> {cs. (Cs cs, Th th) \<in> RAG s}"
+ hence "(Cs cs, Th th) \<in> RAG s" by simp
+ with True neq_th eq_wq show False
+ by (auto simp:next_th_def s_RAG_def cs_holding_def)
+ qed
+ qed
+ finally show ?thesis .
+ qed
+ qed
+ moreover note eq_cnp eq_cnv
+ ultimately show ?thesis by simp
+ qed
+ qed
+ } ultimately show ?thesis by blast
+ qed
+ next
+ case (thread_set thread prio)
+ assume eq_e: "e = Set thread prio"
+ and is_runing: "thread \<in> runing s"
+ show ?thesis
+ proof -
+ from eq_e have eq_cnp: "cntP (e#s) th = cntP s th" by (simp add:cntP_def count_def)
+ from eq_e have eq_cnv: "cntV (e#s) th = cntV s th" by (simp add:cntV_def count_def)
+ have eq_cncs: "cntCS (e#s) th = cntCS s th"
+ unfolding cntCS_def holdents_test
+ by (simp add:RAG_set_unchanged eq_e)
+ from eq_e have eq_readys: "readys (e#s) = readys s"
+ by (simp add:readys_def cs_waiting_def s_waiting_def wq_def,
+ auto simp:Let_def)
+ { assume "th \<noteq> thread"
+ with eq_readys eq_e
+ have "(th \<in> readys (e # s) \<or> th \<notin> threads (e # s)) =
+ (th \<in> readys (s) \<or> th \<notin> threads (s))"
+ by (simp add:threads.simps)
+ with eq_cnp eq_cnv eq_cncs ih is_runing
+ have ?thesis by simp
+ } moreover {
+ assume eq_th: "th = thread"
+ with is_runing ih have " cntP s th = cntV s th + cntCS s th"
+ by (unfold runing_def, auto)
+ moreover from eq_th and eq_readys is_runing have "th \<in> readys (e#s)"
+ by (simp add:runing_def)
+ moreover note eq_cnp eq_cnv eq_cncs
+ ultimately have ?thesis by auto
+ } ultimately show ?thesis by blast
+ qed
+ qed
+ next
+ case vt_nil
+ show ?case
+ by (unfold cntP_def cntV_def cntCS_def,
+ auto simp:count_def holdents_test s_RAG_def wq_def cs_holding_def)
+ qed
+qed
+
+lemma not_thread_cncs:
+ assumes not_in: "th \<notin> threads s"
+ shows "cntCS s th = 0"
+proof -
+ from vt not_in show ?thesis
+ proof(induct arbitrary:th)
+ case (vt_cons s e th)
+ interpret vt_s: valid_trace s using vt_cons(1)
+ by (unfold_locales, simp)
+ assume vt: "vt s"
+ and ih: "\<And>th. th \<notin> threads s \<Longrightarrow> cntCS s th = 0"
+ and stp: "step s e"
+ and not_in: "th \<notin> threads (e # s)"
+ from stp show ?case
+ proof(cases)
+ case (thread_create thread prio)
+ assume eq_e: "e = Create thread prio"
+ and not_in': "thread \<notin> threads s"
+ have "cntCS (e # s) th = cntCS s th"
+ apply (unfold eq_e cntCS_def holdents_test)
+ by (simp add:RAG_create_unchanged)
+ moreover have "th \<notin> threads s"
+ proof -
+ from not_in eq_e show ?thesis by simp
+ qed
+ moreover note ih ultimately show ?thesis by auto
+ next
+ case (thread_exit thread)
+ assume eq_e: "e = Exit thread"
+ and nh: "holdents s thread = {}"
+ have eq_cns: "cntCS (e # s) th = cntCS s th"
+ apply (unfold eq_e cntCS_def holdents_test)
+ by (simp add:RAG_exit_unchanged)
+ show ?thesis
+ proof(cases "th = thread")
+ case True
+ have "cntCS s th = 0" by (unfold cntCS_def, auto simp:nh True)
+ with eq_cns show ?thesis by simp
+ next
+ case False
+ with not_in and eq_e
+ have "th \<notin> threads s" by simp
+ from ih[OF this] and eq_cns show ?thesis by simp
+ qed
+ next
+ case (thread_P thread cs)
+ assume eq_e: "e = P thread cs"
+ and is_runing: "thread \<in> runing s"
+ from assms thread_P ih vt stp thread_P have vtp: "vt (P thread cs#s)" by auto
+ have neq_th: "th \<noteq> thread"
+ proof -
+ from not_in eq_e have "th \<notin> threads s" by simp
+ moreover from is_runing have "thread \<in> threads s"
+ by (simp add:runing_def readys_def)
+ ultimately show ?thesis by auto
+ qed
+ hence "cntCS (e # s) th = cntCS s th "
+ apply (unfold cntCS_def holdents_test eq_e)
+ by (unfold step_RAG_p[OF vtp], auto)
+ moreover have "cntCS s th = 0"
+ proof(rule ih)
+ from not_in eq_e show "th \<notin> threads s" by simp
+ qed
+ ultimately show ?thesis by simp
+ next
+ case (thread_V thread cs)
+ assume eq_e: "e = V thread cs"
+ and is_runing: "thread \<in> runing s"
+ and hold: "holding s thread cs"
+ have neq_th: "th \<noteq> thread"
+ proof -
+ from not_in eq_e have "th \<notin> threads s" by simp
+ moreover from is_runing have "thread \<in> threads s"
+ by (simp add:runing_def readys_def)
+ ultimately show ?thesis by auto
+ qed
+ from assms thread_V vt stp ih
+ have vtv: "vt (V thread cs#s)" by auto
+ then interpret vt_v: valid_trace "(V thread cs#s)"
+ by (unfold_locales, simp)
+ from hold obtain rest
+ where eq_wq: "wq s cs = thread # rest"
+ by (case_tac "wq s cs", auto simp: wq_def s_holding_def)
+ from not_in eq_e eq_wq
+ have "\<not> next_th s thread cs th"
+ apply (auto simp:next_th_def)
+ proof -
+ assume ne: "rest \<noteq> []"
+ and ni: "hd (SOME q. distinct q \<and> set q = set rest) \<notin> threads s" (is "?t \<notin> threads s")
+ have "?t \<in> set rest"
+ proof(rule someI2)
+ from vt_v.wq_distinct[of cs] and eq_wq
+ show "distinct rest \<and> set rest = set rest"
+ by (metis distinct.simps(2) vt_s.wq_distinct)
+ next
+ fix x assume "distinct x \<and> set x = set rest" with ne
+ show "hd x \<in> set rest" by (cases x, auto)
+ qed
+ with eq_wq have "?t \<in> set (wq s cs)" by simp
+ from vt_s.wq_threads[OF this] and ni
+ show False
+ using `hd (SOME q. distinct q \<and> set q = set rest) \<in> set (wq s cs)`
+ ni vt_s.wq_threads by blast
+ qed
+ moreover note neq_th eq_wq
+ ultimately have "cntCS (e # s) th = cntCS s th"
+ by (unfold eq_e cntCS_def holdents_test step_RAG_v[OF vtv], auto)
+ moreover have "cntCS s th = 0"
+ proof(rule ih)
+ from not_in eq_e show "th \<notin> threads s" by simp
+ qed
+ ultimately show ?thesis by simp
+ next
+ case (thread_set thread prio)
+ print_facts
+ assume eq_e: "e = Set thread prio"
+ and is_runing: "thread \<in> runing s"
+ from not_in and eq_e have "th \<notin> threads s" by auto
+ from ih [OF this] and eq_e
+ show ?thesis
+ apply (unfold eq_e cntCS_def holdents_test)
+ by (simp add:RAG_set_unchanged)
+ qed
+ next
+ case vt_nil
+ show ?case
+ by (unfold cntCS_def,
+ auto simp:count_def holdents_test s_RAG_def wq_def cs_holding_def)
+ qed
+qed
+
+end
+
+lemma eq_waiting: "waiting (wq (s::state)) th cs = waiting s th cs"
+ by (auto simp:s_waiting_def cs_waiting_def wq_def)
+
+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
+
+end
+
+lemma cp_eq_cpreced: "cp s th = cpreced (wq s) s th"
+unfolding cp_def wq_def
+apply(induct s rule: schs.induct)
+thm cpreced_initial
+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
+
+context valid_trace
+begin
+
+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
+ apply(simp)
+ done
+ hence eq_max: "Max ((\<lambda>th. preced th s) ` ({th1} \<union> dependants (wq s) th1)) =
+ Max ((\<lambda>th. preced th s) ` ({th2} \<union> dependants (wq s) th2))"
+ (is "Max (?f ` ?A) = Max (?f ` ?B)")
+ unfolding cp_eq_cpreced
+ unfolding cpreced_def .
+ obtain th1' where th1_in: "th1' \<in> ?A" and eq_f_th1: "?f th1' = Max (?f ` ?A)"
+ proof -
+ have h1: "finite (?f ` ?A)"
+ proof -
+ have "finite ?A"
+ proof -
+ have "finite (dependants (wq s) th1)"
+ proof-
+ have "finite {th'. (Th th', Th th1) \<in> (RAG (wq s))\<^sup>+}"
+ proof -
+ let ?F = "\<lambda> (x, y). the_th x"
+ have "{th'. (Th th', Th th1) \<in> (RAG (wq s))\<^sup>+} \<subseteq> ?F ` ((RAG (wq s))\<^sup>+)"
+ apply (auto simp:image_def)
+ by (rule_tac x = "(Th x, Th th1)" in bexI, auto)
+ moreover have "finite \<dots>"
+ proof -
+ from finite_RAG have "finite (RAG s)" .
+ hence "finite ((RAG (wq s))\<^sup>+)"
+ apply (unfold finite_trancl)
+ by (auto simp: s_RAG_def cs_RAG_def wq_def)
+ thus ?thesis by auto
+ qed
+ ultimately show ?thesis by (auto intro:finite_subset)
+ qed
+ thus ?thesis by (simp add:cs_dependants_def)
+ qed
+ thus ?thesis by simp
+ qed
+ thus ?thesis by auto
+ qed
+ moreover have h2: "(?f ` ?A) \<noteq> {}"
+ proof -
+ have "?A \<noteq> {}" by simp
+ thus ?thesis by simp
+ qed
+ from Max_in [OF h1 h2]
+ have "Max (?f ` ?A) \<in> (?f ` ?A)" .
+ thus ?thesis
+ thm cpreced_def
+ unfolding cpreced_def[symmetric]
+ unfolding cp_eq_cpreced[symmetric]
+ unfolding cpreced_def
+ using that[intro] by (auto)
+ qed
+ obtain th2' where th2_in: "th2' \<in> ?B" and eq_f_th2: "?f th2' = Max (?f ` ?B)"
+ proof -
+ have h1: "finite (?f ` ?B)"
+ proof -
+ have "finite ?B"
+ proof -
+ have "finite (dependants (wq s) th2)"
+ proof-
+ have "finite {th'. (Th th', Th th2) \<in> (RAG (wq s))\<^sup>+}"
+ proof -
+ let ?F = "\<lambda> (x, y). the_th x"
+ have "{th'. (Th th', Th th2) \<in> (RAG (wq s))\<^sup>+} \<subseteq> ?F ` ((RAG (wq s))\<^sup>+)"
+ apply (auto simp:image_def)
+ by (rule_tac x = "(Th x, Th th2)" in bexI, auto)
+ moreover have "finite \<dots>"
+ proof -
+ from finite_RAG have "finite (RAG s)" .
+ hence "finite ((RAG (wq s))\<^sup>+)"
+ apply (unfold finite_trancl)
+ by (auto simp: s_RAG_def cs_RAG_def wq_def)
+ thus ?thesis by auto
+ qed
+ ultimately show ?thesis by (auto intro:finite_subset)
+ qed
+ thus ?thesis by (simp add:cs_dependants_def)
+ qed
+ thus ?thesis by simp
+ qed
+ thus ?thesis by auto
+ qed
+ moreover have h2: "(?f ` ?B) \<noteq> {}"
+ proof -
+ have "?B \<noteq> {}" by simp
+ thus ?thesis by simp
+ qed
+ from Max_in [OF h1 h2]
+ have "Max (?f ` ?B) \<in> (?f ` ?B)" .
+ thus ?thesis by (auto intro:that)
+ qed
+ from eq_f_th1 eq_f_th2 eq_max
+ have eq_preced: "preced th1' s = preced th2' s" by auto
+ hence eq_th12: "th1' = th2'"
+ proof (rule preced_unique)
+ from th1_in have "th1' = th1 \<or> (th1' \<in> dependants (wq s) th1)" by simp
+ thus "th1' \<in> threads s"
+ proof
+ assume "th1' \<in> dependants (wq s) th1"
+ hence "(Th th1') \<in> Domain ((RAG s)^+)"
+ apply (unfold cs_dependants_def cs_RAG_def s_RAG_def)
+ by (auto simp:Domain_def)
+ hence "(Th th1') \<in> Domain (RAG s)" by (simp add:trancl_domain)
+ from dm_RAG_threads[OF this] show ?thesis .
+ next
+ assume "th1' = th1"
+ with runing_1 show ?thesis
+ by (unfold runing_def readys_def, auto)
+ qed
+ next
+ from th2_in have "th2' = th2 \<or> (th2' \<in> dependants (wq s) th2)" by simp
+ thus "th2' \<in> threads s"
+ proof
+ assume "th2' \<in> dependants (wq s) th2"
+ hence "(Th th2') \<in> Domain ((RAG s)^+)"
+ apply (unfold cs_dependants_def cs_RAG_def s_RAG_def)
+ by (auto simp:Domain_def)
+ hence "(Th th2') \<in> Domain (RAG s)" by (simp add:trancl_domain)
+ from dm_RAG_threads[OF this] show ?thesis .
+ next
+ assume "th2' = th2"
+ with runing_2 show ?thesis
+ by (unfold runing_def readys_def, auto)
+ qed
+ qed
+ from th1_in have "th1' = th1 \<or> th1' \<in> dependants (wq s) th1" by simp
+ thus ?thesis
+ proof
+ assume eq_th': "th1' = th1"
+ from th2_in have "th2' = th2 \<or> th2' \<in> dependants (wq s) th2" by simp
+ thus ?thesis
+ proof
+ assume "th2' = th2" thus ?thesis using eq_th' eq_th12 by simp
+ next
+ assume "th2' \<in> dependants (wq s) th2"
+ with eq_th12 eq_th' have "th1 \<in> dependants (wq s) th2" by simp
+ hence "(Th th1, Th th2) \<in> (RAG s)^+"
+ by (unfold cs_dependants_def s_RAG_def cs_RAG_def, simp)
+ hence "Th th1 \<in> Domain ((RAG s)^+)"
+ apply (unfold cs_dependants_def cs_RAG_def s_RAG_def)
+ by (auto simp:Domain_def)
+ hence "Th th1 \<in> Domain (RAG s)" by (simp add:trancl_domain)
+ then obtain n where d: "(Th th1, n) \<in> RAG s" by (auto simp:Domain_def)
+ from RAG_target_th [OF this]
+ obtain cs' where "n = Cs cs'" by auto
+ with d have "(Th th1, Cs cs') \<in> RAG s" by simp
+ with runing_1 have "False"
+ apply (unfold runing_def readys_def s_RAG_def)
+ by (auto simp:eq_waiting)
+ thus ?thesis by simp
+ qed
+ next
+ assume th1'_in: "th1' \<in> dependants (wq s) th1"
+ from th2_in have "th2' = th2 \<or> th2' \<in> dependants (wq s) th2" by simp
+ thus ?thesis
+ proof
+ assume "th2' = th2"
+ with th1'_in eq_th12 have "th2 \<in> dependants (wq s) th1" by simp
+ hence "(Th th2, Th th1) \<in> (RAG s)^+"
+ by (unfold cs_dependants_def s_RAG_def cs_RAG_def, simp)
+ hence "Th th2 \<in> Domain ((RAG s)^+)"
+ apply (unfold cs_dependants_def cs_RAG_def s_RAG_def)
+ by (auto simp:Domain_def)
+ hence "Th th2 \<in> Domain (RAG s)" by (simp add:trancl_domain)
+ then obtain n where d: "(Th th2, n) \<in> RAG s" by (auto simp:Domain_def)
+ from RAG_target_th [OF this]
+ obtain cs' where "n = Cs cs'" by auto
+ with d have "(Th th2, Cs cs') \<in> RAG s" by simp
+ with runing_2 have "False"
+ apply (unfold runing_def readys_def s_RAG_def)
+ by (auto simp:eq_waiting)
+ thus ?thesis by simp
+ next
+ assume "th2' \<in> dependants (wq s) th2"
+ with eq_th12 have "th1' \<in> dependants (wq s) th2" by simp
+ hence h1: "(Th th1', Th th2) \<in> (RAG s)^+"
+ by (unfold cs_dependants_def s_RAG_def cs_RAG_def, simp)
+ from th1'_in have h2: "(Th th1', Th th1) \<in> (RAG s)^+"
+ by (unfold cs_dependants_def s_RAG_def cs_RAG_def, simp)
+ show ?thesis
+ proof(rule dchain_unique[OF h1 _ h2, symmetric])
+ from runing_1 show "th1 \<in> readys s" by (simp add:runing_def)
+ from runing_2 show "th2 \<in> readys s" by (simp add:runing_def)
+ qed
+ qed
+ qed
+qed
+
+
+lemma "card (runing s) \<le> 1"
+apply(subgoal_tac "finite (runing s)")
+prefer 2
+apply (metis finite_nat_set_iff_bounded lessI runing_unique)
+apply(rule ccontr)
+apply(simp)
+apply(case_tac "Suc (Suc 0) \<le> card (runing s)")
+apply(subst (asm) card_le_Suc_iff)
+apply(simp)
+apply(auto)[1]
+apply (metis insertCI runing_unique)
+apply(auto)
+done
+
+end
+
+
+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 length_down_to_in:
+ assumes le_ij: "i \<le> j"
+ and le_js: "j \<le> length s"
+ shows "length (down_to j i s) = j - i"
+proof -
+ have "length (down_to j i s) = length (from_to i j (rev s))"
+ by (unfold down_to_def, auto)
+ also have "\<dots> = j - i"
+ proof(rule length_from_to_in[OF le_ij])
+ from le_js show "j \<le> length (rev s)" by simp
+ qed
+ finally show ?thesis .
+qed
+
+
+lemma moment_head:
+ assumes le_it: "Suc i \<le> length t"
+ obtains e where "moment (Suc i) t = e#moment i t"
+proof -
+ have "i \<le> Suc i" by simp
+ from length_down_to_in [OF this le_it]
+ have "length (down_to (Suc i) i t) = 1" by auto
+ then obtain e where "down_to (Suc i) i t = [e]"
+ apply (cases "(down_to (Suc i) i t)") by auto
+ moreover have "down_to (Suc i) 0 t = down_to (Suc i) i t @ down_to i 0 t"
+ by (rule down_to_conc[symmetric], auto)
+ ultimately have eq_me: "moment (Suc i) t = e#(moment i t)"
+ by (auto simp:down_to_moment)
+ from that [OF this] show ?thesis .
+qed
+
+context valid_trace
+begin
+
+lemma cnp_cnv_eq:
+ assumes "th \<notin> threads s"
+ shows "cntP s th = cntV s th"
+ using assms
+ using cnp_cnv_cncs not_thread_cncs by auto
+
+end
+
+
+lemma eq_RAG:
+ "RAG (wq s) = RAG s"
+by (unfold cs_RAG_def s_RAG_def, auto)
+
+context valid_trace
+begin
+
+lemma count_eq_dependants:
+ assumes eq_pv: "cntP s th = cntV s th"
+ shows "dependants (wq s) th = {}"
+proof -
+ from cnp_cnv_cncs and eq_pv
+ have "cntCS s th = 0"
+ by (auto split:if_splits)
+ moreover have "finite {cs. (Cs cs, Th th) \<in> RAG s}"
+ proof -
+ from finite_holding[of th] show ?thesis
+ by (simp add:holdents_test)
+ qed
+ ultimately have h: "{cs. (Cs cs, Th th) \<in> RAG s} = {}"
+ by (unfold cntCS_def holdents_test cs_dependants_def, auto)
+ show ?thesis
+ proof(unfold cs_dependants_def)
+ { assume "{th'. (Th th', Th th) \<in> (RAG (wq s))\<^sup>+} \<noteq> {}"
+ then obtain th' where "(Th th', Th th) \<in> (RAG (wq s))\<^sup>+" by auto
+ hence "False"
+ proof(cases)
+ assume "(Th th', Th th) \<in> RAG (wq s)"
+ thus "False" by (auto simp:cs_RAG_def)
+ next
+ fix c
+ assume "(c, Th th) \<in> RAG (wq s)"
+ with h and eq_RAG show "False"
+ by (cases c, auto simp:cs_RAG_def)
+ qed
+ } thus "{th'. (Th th', Th th) \<in> (RAG (wq s))\<^sup>+} = {}" by auto
+ qed
+qed
+
+lemma dependants_threads:
+ shows "dependants (wq s) th \<subseteq> threads s"
+proof
+ { fix th th'
+ assume h: "th \<in> {th'a. (Th th'a, Th th') \<in> (RAG (wq s))\<^sup>+}"
+ have "Th th \<in> Domain (RAG s)"
+ proof -
+ from h obtain th' where "(Th th, Th th') \<in> (RAG (wq s))\<^sup>+" by auto
+ hence "(Th th) \<in> Domain ( (RAG (wq s))\<^sup>+)" by (auto simp:Domain_def)
+ with trancl_domain have "(Th th) \<in> Domain (RAG (wq s))" by simp
+ thus ?thesis using eq_RAG by simp
+ qed
+ from dm_RAG_threads[OF this]
+ have "th \<in> threads s" .
+ } note hh = this
+ fix th1
+ assume "th1 \<in> dependants (wq s) th"
+ hence "th1 \<in> {th'a. (Th th'a, Th th) \<in> (RAG (wq s))\<^sup>+}"
+ by (unfold cs_dependants_def, simp)
+ from hh [OF this] show "th1 \<in> threads s" .
+qed
+
+lemma finite_threads:
+ shows "finite (threads s)"
+using vt by (induct) (auto elim: step.cases)
+
+end
+
+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
+
+context valid_trace
+begin
+
+lemma cp_le:
+ assumes th_in: "th \<in> threads s"
+ shows "cp s th \<le> Max ((\<lambda> th. (preced th s)) ` threads s)"
+proof(unfold cp_eq_cpreced cpreced_def cs_dependants_def)
+ show "Max ((\<lambda>th. preced th s) ` ({th} \<union> {th'. (Th th', Th th) \<in> (RAG (wq s))\<^sup>+}))
+ \<le> Max ((\<lambda>th. preced th s) ` threads s)"
+ (is "Max (?f ` ?A) \<le> Max (?f ` ?B)")
+ proof(rule Max_f_mono)
+ show "{th} \<union> {th'. (Th th', Th th) \<in> (RAG (wq s))\<^sup>+} \<noteq> {}" by simp
+ next
+ from finite_threads
+ show "finite (threads s)" .
+ next
+ from th_in
+ show "{th} \<union> {th'. (Th th', Th th) \<in> (RAG (wq s))\<^sup>+} \<subseteq> threads s"
+ apply (auto simp:Domain_def)
+ apply (rule_tac dm_RAG_threads)
+ apply (unfold trancl_domain [of "RAG s", symmetric])
+ by (unfold cs_RAG_def s_RAG_def, auto simp:Domain_def)
+ qed
+qed
+
+lemma le_cp:
+ shows "preced th s \<le> cp s th"
+proof(unfold cp_eq_cpreced preced_def cpreced_def, simp)
+ show "Prc (priority th s) (last_set th s)
+ \<le> Max (insert (Prc (priority th s) (last_set th s))
+ ((\<lambda>th. Prc (priority th s) (last_set th s)) ` dependants (wq s) th))"
+ (is "?l \<le> Max (insert ?l ?A)")
+ proof(cases "?A = {}")
+ case False
+ have "finite ?A" (is "finite (?f ` ?B)")
+ proof -
+ have "finite ?B"
+ proof-
+ have "finite {th'. (Th th', Th th) \<in> (RAG (wq s))\<^sup>+}"
+ proof -
+ let ?F = "\<lambda> (x, y). the_th x"
+ have "{th'. (Th th', Th th) \<in> (RAG (wq s))\<^sup>+} \<subseteq> ?F ` ((RAG (wq s))\<^sup>+)"
+ apply (auto simp:image_def)
+ by (rule_tac x = "(Th x, Th th)" in bexI, auto)
+ moreover have "finite \<dots>"
+ proof -
+ from finite_RAG have "finite (RAG s)" .
+ hence "finite ((RAG (wq s))\<^sup>+)"
+ apply (unfold finite_trancl)
+ by (auto simp: s_RAG_def cs_RAG_def wq_def)
+ thus ?thesis by auto
+ qed
+ ultimately show ?thesis by (auto intro:finite_subset)
+ qed
+ thus ?thesis by (simp add:cs_dependants_def)
+ qed
+ thus ?thesis by simp
+ qed
+ from Max_insert [OF this False, of ?l] show ?thesis by auto
+ next
+ case True
+ thus ?thesis by auto
+ qed
+qed
+
+lemma max_cp_eq:
+ shows "Max ((cp s) ` threads s) = Max ((\<lambda> th. (preced th s)) ` threads s)"
+ (is "?l = ?r")
+proof(cases "threads s = {}")
+ case True
+ thus ?thesis by auto
+next
+ case False
+ have "?l \<in> ((cp s) ` threads s)"
+ proof(rule Max_in)
+ from finite_threads
+ show "finite (cp s ` threads s)" by auto
+ next
+ from False show "cp s ` threads s \<noteq> {}" by auto
+ qed
+ then obtain th
+ where th_in: "th \<in> threads s" and eq_l: "?l = cp s th" by auto
+ have "\<dots> \<le> ?r" by (rule cp_le[OF th_in])
+ moreover have "?r \<le> cp s th" (is "Max (?f ` ?A) \<le> cp s th")
+ proof -
+ have "?r \<in> (?f ` ?A)"
+ proof(rule Max_in)
+ from finite_threads
+ show " finite ((\<lambda>th. preced th s) ` threads s)" by auto
+ next
+ from False show " (\<lambda>th. preced th s) ` threads s \<noteq> {}" by auto
+ qed
+ then obtain th' where
+ th_in': "th' \<in> ?A " and eq_r: "?r = ?f th'" by auto
+ from le_cp [of th'] eq_r
+ have "?r \<le> cp s th'" by auto
+ moreover have "\<dots> \<le> cp s th"
+ proof(fold eq_l)
+ show " cp s th' \<le> Max (cp s ` threads s)"
+ proof(rule Max_ge)
+ from th_in' show "cp s th' \<in> cp s ` threads s"
+ by auto
+ next
+ from finite_threads
+ show "finite (cp s ` threads s)" by auto
+ qed
+ qed
+ ultimately show ?thesis by auto
+ qed
+ ultimately show ?thesis using eq_l by auto
+qed
+
+lemma max_cp_readys_threads_pre:
+ assumes np: "threads s \<noteq> {}"
+ shows "Max (cp s ` readys s) = Max (cp s ` threads s)"
+proof(unfold max_cp_eq)
+ show "Max (cp s ` readys s) = Max ((\<lambda>th. preced th s) ` threads s)"
+ proof -
+ let ?p = "Max ((\<lambda>th. preced th s) ` threads s)"
+ let ?f = "(\<lambda>th. preced th s)"
+ have "?p \<in> ((\<lambda>th. preced th s) ` threads s)"
+ proof(rule Max_in)
+ from finite_threads show "finite (?f ` threads s)" by simp
+ next
+ from np show "?f ` threads s \<noteq> {}" by simp
+ qed
+ then obtain tm where tm_max: "?f tm = ?p" and tm_in: "tm \<in> threads s"
+ by (auto simp:Image_def)
+ from th_chain_to_ready [OF tm_in]
+ have "tm \<in> readys s \<or> (\<exists>th'. th' \<in> readys s \<and> (Th tm, Th th') \<in> (RAG s)\<^sup>+)" .
+ thus ?thesis
+ proof
+ assume "\<exists>th'. th' \<in> readys s \<and> (Th tm, Th th') \<in> (RAG s)\<^sup>+ "
+ then obtain th' where th'_in: "th' \<in> readys s"
+ and tm_chain:"(Th tm, Th th') \<in> (RAG s)\<^sup>+" by auto
+ have "cp s th' = ?f tm"
+ proof(subst cp_eq_cpreced, subst cpreced_def, rule Max_eqI)
+ from dependants_threads finite_threads
+ show "finite ((\<lambda>th. preced th s) ` ({th'} \<union> dependants (wq s) th'))"
+ by (auto intro:finite_subset)
+ next
+ fix p assume p_in: "p \<in> (\<lambda>th. preced th s) ` ({th'} \<union> dependants (wq s) th')"
+ from tm_max have " preced tm s = Max ((\<lambda>th. preced th s) ` threads s)" .
+ moreover have "p \<le> \<dots>"
+ proof(rule Max_ge)
+ from finite_threads
+ show "finite ((\<lambda>th. preced th s) ` threads s)" by simp
+ next
+ from p_in and th'_in and dependants_threads[of th']
+ show "p \<in> (\<lambda>th. preced th s) ` threads s"
+ by (auto simp:readys_def)
+ qed
+ ultimately show "p \<le> preced tm s" by auto
+ next
+ show "preced tm s \<in> (\<lambda>th. preced th s) ` ({th'} \<union> dependants (wq s) th')"
+ proof -
+ from tm_chain
+ have "tm \<in> dependants (wq s) th'"
+ by (unfold cs_dependants_def s_RAG_def cs_RAG_def, auto)
+ thus ?thesis by auto
+ qed
+ qed
+ with tm_max
+ have h: "cp s th' = Max ((\<lambda>th. preced th s) ` threads s)" by simp
+ show ?thesis
+ proof (fold h, rule Max_eqI)
+ fix q
+ assume "q \<in> cp s ` readys s"
+ then obtain th1 where th1_in: "th1 \<in> readys s"
+ and eq_q: "q = cp s th1" by auto
+ show "q \<le> cp s th'"
+ apply (unfold h eq_q)
+ apply (unfold cp_eq_cpreced cpreced_def)
+ apply (rule Max_mono)
+ proof -
+ from dependants_threads [of th1] th1_in
+ show "(\<lambda>th. preced th s) ` ({th1} \<union> dependants (wq s) th1) \<subseteq>
+ (\<lambda>th. preced th s) ` threads s"
+ by (auto simp:readys_def)
+ next
+ show "(\<lambda>th. preced th s) ` ({th1} \<union> dependants (wq s) th1) \<noteq> {}" by simp
+ next
+ from finite_threads
+ show " finite ((\<lambda>th. preced th s) ` threads s)" by simp
+ qed
+ next
+ from finite_threads
+ show "finite (cp s ` readys s)" by (auto simp:readys_def)
+ next
+ from th'_in
+ show "cp s th' \<in> cp s ` readys s" by simp
+ qed
+ next
+ assume tm_ready: "tm \<in> readys s"
+ show ?thesis
+ proof(fold tm_max)
+ have cp_eq_p: "cp s tm = preced tm s"
+ proof(unfold cp_eq_cpreced cpreced_def, rule Max_eqI)
+ fix y
+ assume hy: "y \<in> (\<lambda>th. preced th s) ` ({tm} \<union> dependants (wq s) tm)"
+ show "y \<le> preced tm s"
+ proof -
+ { fix y'
+ assume hy' : "y' \<in> ((\<lambda>th. preced th s) ` dependants (wq s) tm)"
+ have "y' \<le> preced tm s"
+ proof(unfold tm_max, rule Max_ge)
+ from hy' dependants_threads[of tm]
+ show "y' \<in> (\<lambda>th. preced th s) ` threads s" by auto
+ next
+ from finite_threads
+ show "finite ((\<lambda>th. preced th s) ` threads s)" by simp
+ qed
+ } with hy show ?thesis by auto
+ qed
+ next
+ from dependants_threads[of tm] finite_threads
+ show "finite ((\<lambda>th. preced th s) ` ({tm} \<union> dependants (wq s) tm))"
+ by (auto intro:finite_subset)
+ next
+ show "preced tm s \<in> (\<lambda>th. preced th s) ` ({tm} \<union> dependants (wq s) tm)"
+ by simp
+ qed
+ moreover have "Max (cp s ` readys s) = cp s tm"
+ proof(rule Max_eqI)
+ from tm_ready show "cp s tm \<in> cp s ` readys s" by simp
+ next
+ from finite_threads
+ show "finite (cp s ` readys s)" by (auto simp:readys_def)
+ next
+ fix y assume "y \<in> cp s ` readys s"
+ then obtain th1 where th1_readys: "th1 \<in> readys s"
+ and h: "y = cp s th1" by auto
+ show "y \<le> cp s tm"
+ apply(unfold cp_eq_p h)
+ apply(unfold cp_eq_cpreced cpreced_def tm_max, rule Max_mono)
+ proof -
+ from finite_threads
+ show "finite ((\<lambda>th. preced th s) ` threads s)" by simp
+ next
+ show "(\<lambda>th. preced th s) ` ({th1} \<union> dependants (wq s) th1) \<noteq> {}"
+ by simp
+ next
+ from dependants_threads[of th1] th1_readys
+ show "(\<lambda>th. preced th s) ` ({th1} \<union> dependants (wq s) th1)
+ \<subseteq> (\<lambda>th. preced th s) ` threads s"
+ by (auto simp:readys_def)
+ qed
+ qed
+ ultimately show " Max (cp s ` readys s) = preced tm s" by simp
+ qed
+ qed
+ qed
+qed
+
+text {* (* ccc *) \noindent
+ Since the current precedence of the threads in ready queue will always be boosted,
+ there must be one inside it has the maximum precedence of the whole system.
+*}
+lemma max_cp_readys_threads:
+ shows "Max (cp s ` readys s) = Max (cp s ` threads s)"
+proof(cases "threads s = {}")
+ case True
+ thus ?thesis
+ by (auto simp:readys_def)
+next
+ case False
+ show ?thesis by (rule max_cp_readys_threads_pre[OF False])
+qed
+
+end
+
+lemma eq_holding: "holding (wq s) th cs = holding s th cs"
+ apply (unfold s_holding_def cs_holding_def wq_def, simp)
+ done
+
+lemma f_image_eq:
+ assumes h: "\<And> a. a \<in> A \<Longrightarrow> f a = g a"
+ shows "f ` A = g ` A"
+proof
+ show "f ` A \<subseteq> g ` A"
+ by(rule image_subsetI, auto intro:h)
+next
+ show "g ` A \<subseteq> f ` A"
+ by (rule image_subsetI, auto intro:h[symmetric])
+qed
+
+
+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 cnp_cnv_cncs
+ have eq_cnt: "cntP s th =
+ cntV s th + (if th \<in> readys s \<or> th \<notin> threads s then cntCS s th else cntCS s th + 1)" .
+ hence cncs_zero: "cntCS s th = 0"
+ by (auto simp:eq_pv split:if_splits)
+ with eq_cnt
+ have "th \<in> readys s \<or> th \<notin> threads s" by (auto simp:eq_pv)
+ thus ?thesis
+ proof
+ assume "th \<notin> threads s"
+ with range_in 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 card_0_eq [OF finite_holding] and cncs_zero
+ have "holdents s th = {}"
+ by (simp add:cntCS_def)
+ thus ?thesis
+ apply(auto simp:holdents_test)
+ apply(case_tac a)
+ apply(auto simp:holdents_test s_RAG_def)
+ done
+ 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 -
+ from cnp_cnv_cncs
+ have eq_pv: " cntP s th =
+ cntV s th + (if th \<in> readys s \<or> th \<notin> threads s then cntCS s th else cntCS s th + 1)" .
+ 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:eq_waiting s_RAG_def)
+ with cncs_z and eq_pv show ?thesis by simp
+ next
+ case False
+ with cncs_z and eq_pv show ?thesis by simp
+ qed
+qed
+
+lemma detached_eq:
+ shows "(detached s th) = (cntP s th = cntV s th)"
+ by (insert vt, auto intro:detached_intro detached_elim)
+
+end
+
+text {*
+ The lemmas in this .thy file are all obvious lemmas, however, they still needs to be derived
+ from the concise and miniature model of PIP given in PrioGDef.thy.
+*}
+
+lemma eq_dependants: "dependants (wq s) = dependants s"
+ by (simp add: s_dependants_abv wq_def)
+
+lemma next_th_unique:
+ assumes nt1: "next_th s th cs th1"
+ and nt2: "next_th s th cs th2"
+ shows "th1 = th2"
+using assms by (unfold next_th_def, auto)
+
+lemma birth_time_lt: "s \<noteq> [] \<Longrightarrow> last_set th s < length s"
+ apply (induct s, simp)
+proof -
+ fix a s
+ assume ih: "s \<noteq> [] \<Longrightarrow> last_set th s < length s"
+ and eq_as: "a # s \<noteq> []"
+ show "last_set th (a # s) < length (a # s)"
+ proof(cases "s \<noteq> []")
+ case False
+ from False show ?thesis
+ by (cases a, auto simp:last_set.simps)
+ next
+ case True
+ from ih [OF True] show ?thesis
+ by (cases a, auto simp:last_set.simps)
+ qed
+qed
+
+lemma th_in_ne: "th \<in> threads s \<Longrightarrow> s \<noteq> []"
+ by (induct s, auto simp:threads.simps)
+
+lemma preced_tm_lt: "th \<in> threads s \<Longrightarrow> preced th s = Prc x y \<Longrightarrow> y < length s"
+ apply (drule_tac th_in_ne)
+ by (unfold preced_def, auto intro: birth_time_lt)
lemma inj_the_preced:
"inj_on (the_preced s) (threads s)"
by (metis inj_onI preced_unique the_preced_def)
-text {* @{term "the_thread"} extracts thread out of RAG node. *}
-fun the_thread :: "node \<Rightarrow> thread" where
- "the_thread (Th th) = th"
-
-text {* The following @{text "wRAG"} is the waiting sub-graph of @{text "RAG"}. *}
-definition "wRAG (s::state) = {(Th th, Cs cs) | th cs. waiting s th cs}"
-
-text {* The following @{text "hRAG"} is the holding sub-graph of @{text "RAG"}. *}
-definition "hRAG (s::state) = {(Cs cs, Th th) | th cs. holding s th cs}"
-
-text {* The following lemma splits @{term "RAG"} graph into the above two sub-graphs. *}
-lemma RAG_split: "RAG s = (wRAG s \<union> hRAG s)"
- by (unfold s_RAG_abv wRAG_def hRAG_def s_waiting_abv
- s_holding_abv cs_RAG_def, auto)
-
-text {*
- The following @{text "tRAG"} is the thread-graph derived from @{term "RAG"}.
- It characterizes the dependency between threads when calculating current
- precedences. It is defined as the composition of the above two sub-graphs,
- names @{term "wRAG"} and @{term "hRAG"}.
- *}
-definition "tRAG s = wRAG s O hRAG s"
-
-(* ccc *)
-
-definition "cp_gen s x =
- Max ((the_preced s \<circ> the_thread) ` subtree (tRAG s) x)"
-
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}"
@@ -503,7 +3664,6 @@
end
-
sublocale valid_trace < rtree_RAG: rtree "RAG s"
proof
show "single_valued (RAG s)"
@@ -530,7 +3690,6 @@
next
show "fsubtree_axioms (RAG s)"
proof(unfold fsubtree_axioms_def)
- find_theorems wf RAG
from wf_RAG show "wf (RAG s)" .
qed
qed
@@ -729,912 +3888,4 @@
definition cps:: "state \<Rightarrow> (thread \<times> precedence) set"
where "cps s = {(th, cp s th) | th . th \<in> threads s}"
-
-text {* (* ddd *)
- One beauty of our modelling is that we follow the definitional extension tradition of HOL.
- The benefit of such a concise and miniature model is that large number of intuitively
- obvious facts are derived as lemmas, rather than asserted as axioms.
-*}
-
-text {*
- However, the lemmas in the forthcoming several locales are no longer
- obvious. These lemmas show how the current precedences should be recalculated
- after every execution step (in our model, every step is represented by an event,
- which in turn, represents a system call, or operation). Each operation is
- treated in a separate locale.
-
- The complication of current precedence recalculation comes
- because the changing of RAG needs to be taken into account,
- in addition to the changing of precedence.
- The reason RAG changing affects current precedence is that,
- according to the definition, current precedence
- of a thread is the maximum of the precedences of its dependants,
- where the dependants are defined in terms of RAG.
-
- Therefore, each operation, lemmas concerning the change of the precedences
- and RAG are derived first, so that the lemmas about
- current precedence recalculation can be based on.
-*}
-
-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
-begin
-
-text {* (* ddd *)
- The following two lemmas confirm that @{text "Set"}-operating only changes the precedence
- of the initiating thread.
-*}
-
-lemma eq_preced:
- assumes "th' \<noteq> th"
- shows "preced th' s = preced th' s'"
-proof -
- from assms show ?thesis
- by (unfold s_def, auto simp:preced_def)
-qed
-
-lemma eq_the_preced:
- fixes th'
- assumes "th' \<noteq> th"
- shows "the_preced 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 the priority change of @{text "th"}
- only affects those threads, which as @{text "Th th"} in their sub-trees.
-
- The proof of this lemma is simplified by using the alternative definition of @{text "cp"}.
-*}
-
-lemma eq_cp_pre:
- fixes th'
- assumes nd: "Th th \<notin> subtree (RAG s') (Th th')"
- shows "cp 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')})"
- (is "Max (?f ` ?S1) = Max (?g ` ?S2)")
- proof -
- -- {* The base sets are equal. *}
- have "?S1 = ?S2" using eq_dep by simp
- -- {* The function values on the base set are equal as well. *}
- moreover have "\<forall> e \<in> ?S2. ?f e = ?g e"
- proof
- fix th1
- 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" .
- qed
- -- {* Therefore, the image of the functions are equal. *}
- ultimately have "(?f ` ?S1) = (?g ` ?S2)" by (auto intro!:f_image_eq)
- thus ?thesis by simp
- qed
- thus ?thesis by (simp add:cp_alt_def)
-qed
-
-text {*
- The following lemma shows that @{term "th"} is not in the
- sub-tree of any other thread.
-*}
-lemma th_in_no_subtree:
- assumes "th' \<noteq> 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
- find_theorems readys subtree
- from vat_s'.readys_in_no_subtree[OF this assms(1)]
- show ?thesis by blast
-qed
-
-text {*
- By combining @{thm "eq_cp_pre"} and @{thm "th_in_no_subtree"},
- it is obvious that the change of priority only affects the @{text "cp"}-value
- of the initiating thread @{text "th"}.
-*}
-lemma eq_cp:
- fixes th'
- assumes "th' \<noteq> th"
- shows "cp s th' = cp s' th'"
- by (rule eq_cp_pre[OF th_in_no_subtree[OF assms]])
-
end
-
-text {*
- 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
-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) = {}"
-proof -
- from vat_s'.readys_root[OF ready_th_s']
- show ?thesis
- by (unfold root_def, simp)
-qed
-
-lemma holding_th: "holding s' th cs"
-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
- show ?thesis
- by (unfold s_RAG_def holding_eq, auto)
-qed
-
-lemma ancestors_cs:
- "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
- 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 {*
- The following @{text "step_v_cps_nt"} is the sub-locale for @{text "V"}-operation,
- 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
-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 ancestors_th':
- "ancestors (RAG s') (Th th') = {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
- 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
-
-lemma subtree_kept:
- assumes "th1 \<notin> {th, th'}"
- shows "subtree (RAG 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')}"
- 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) = {}"
- proof -
- have "(Th th) \<notin> subtree (RAG s') (Th th1)"
- proof(rule subtree_refute)
- 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)"
- proof(rule subtree_refute)
- 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
- 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)"
- proof(rule subtree_refute)
- show "Th th1 \<notin> ancestors (RAG s' - {(Cs cs, Th th), (Th th', Cs cs)}) (Th th')"
- (is "_ \<notin> ?R")
- proof -
- have "?R \<subseteq> ancestors (RAG s') (Th th')" 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
- 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)
-
-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
-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
-
-lemma subtree_kept:
- assumes "th1 \<noteq> th"
- shows "subtree (RAG 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) = {}"
- proof -
- have "(Th th) \<notin> subtree (RAG s') (Th th1)"
- proof(rule subtree_refute)
- 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
- thus ?thesis by auto
- qed
-qed
-
-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)
-
-lemma subtree_cs: "subtree (RAG s') (Cs cs) = {Cs cs}"
-proof -
- { fix 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
- 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 this[unfolded s_RAG_def]
- 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
- qed
- } note h = this
- { fix n
- 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)"
- 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}"
-find_theorems "subtree" "_ - _" RAG
-proof(unfold RAG_s, fold subtree_cs, rule vat_s'.rtree_RAG.subtree_del_inside)
- from edge_of_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)
-
-lemma eq_cp:
- fixes th'
- shows "cp 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
-
-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
-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 in_no_others_subtree:
- assumes "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 root_th show ?thesis by (auto simp:root_def)
- qed
-qed
-
-lemma preced_kept: "the_preced s = the_preced s'"
- by (auto simp: s_def the_preced_def preced_def)
-
-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
-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)
- from in_no_others_subtree[OF assms]
- show "Th th \<notin> subtree (RAG s') (Th th')" .
-qed
-
-lemma cp_kept:
- assumes "th' \<noteq> th"
- shows "cp 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')})"
- by (unfold preced_kept subtree_kept[OF assms], simp)
- thus ?thesis by (unfold cp_alt_def, simp)
-qed
-
-end
-
-context step_P_cps_ne
-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
-
-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 tRAG_s:
- "tRAG s = tRAG s' \<union> {(Th th, Th th')}"
- using RAG_tRAG_transfer[OF RAG_s cs_held] .
-
-lemma cp_kept:
- assumes "Th th'' \<notin> ancestors (tRAG s) (Th th)"
- shows "cp s th'' = cp s' th''"
-proof -
- have h: "subtree (tRAG s) (Th th'') = subtree (tRAG s') (Th th'')"
- proof -
- have "Th th' \<notin> subtree (tRAG s') (Th th'')"
- proof
- assume "Th th' \<in> subtree (tRAG s') (Th th'')"
- thus False
- proof(rule subtreeE)
- assume "Th th' = 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')"
- proof(rule ancestors_mono)
- show "tRAG s' \<subseteq> tRAG 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)"
- by (unfold tRAG_s, auto simp:ancestors_def)
- ultimately have "Th th'' \<in> ancestors (tRAG 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'')" .
- 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"
- using assms(3)
-proof(induct rule:wf_induct[OF vat_s.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]
- have "?L =
- Max ({the_preced s th2} \<union> cp_gen s ` RTree.children (tRAG s) x)" .
- also have "... =
- 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"
- proof -
- have "RTree.children (tRAG s) x = RTree.children (tRAG s') x"
- proof(unfold tRAG_s, rule children_union_kept)
- have start: "(Th th, Th th') \<in> tRAG s"
- by (unfold tRAG_s, auto)
- note x_u = 1(2)
- show "x \<notin> Range {(Th th, Th th')}"
- proof
- assume "x \<in> Range {(Th th, Th th')}"
- hence eq_x: "x = Th th'" using RangeE by auto
- show False
- proof(cases rule:vat_s.rtree_s.ancestors_headE[OF assms(1) start])
- case 1
- from x_u[folded this, unfolded eq_x] vat_s.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)
- 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")
- 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])
- case in_ch
- show ?thesis
- proof(cases "a = u")
- case True
- from assms(2)[folded this] show ?thesis .
- next
- case False
- have a_not_in: "a \<notin> ancestors (tRAG s) (Th th)"
- proof
- assume a_in': "a \<in> ancestors (tRAG 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
- next
- from assms(1) in_ch show "u \<in> ancestors (tRAG s) (Th th) \<inter>
- RTree.children (tRAG 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" .
- 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
- 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 1(1)[rule_format, OF this h(1)]
- have eq_cp_gen: "cp_gen 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)"
- proof
- assume a_in': "a \<in> ancestors (tRAG 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)"
- by (auto simp:ancestors_def)
- with h(2) show " z \<in> ancestors (tRAG s) (Th th) \<inter>
- RTree.children (tRAG s) x" by auto
- next
- from a_in a_in'
- show "a \<in> ancestors (tRAG s) (Th th) \<inter> RTree.children (tRAG 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" .
- from this[unfolded cp_gen_def_cond[OF eq_a], folded eq_a]
- show ?thesis .
- qed
- qed
- qed
- ultimately show ?thesis by metis
- qed
- ultimately show ?thesis by simp
- qed
- also have "... = ?R"
- by (fold vat_s'.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''"
-proof -
- have "cp_gen 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
- qed
- with cp_gen_def_cond[OF refl[of "Th th''"]]
- show ?thesis by metis
-qed
-
-end
-
-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)
-
-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
-
-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 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 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 eq_cp:
- assumes neq_th: "th' \<noteq> th"
- shows "cp 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')"
- proof(unfold tRAG_kept, rule f_image_eq)
- fix a
- 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
- from ancestors_Field[OF 2(2)]
- and that show ?thesis by (unfold tRAG_alt_def, auto)
- qed auto
- have neq_th_a: "th_a \<noteq> th"
- proof -
- have "(Th th) \<notin> subtree (tRAG s') (Th th')"
- proof
- assume "Th th \<in> subtree (tRAG s') (Th th')"
- thus False
- proof(cases rule:subtreeE)
- case 2
- from ancestors_Field[OF this(2)]
- and th_not_in[unfolded Field_def]
- show ?thesis by auto
- qed (insert assms, auto)
- qed
- 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"
- 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) = {}"
-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)
- 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)
-
-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
-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)
-
-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 th_holdents: "holdents s' th = {}"
-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')"
- proof
- 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)
- qed
- 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"
- by (unfold Domain_iff s_RAG_def, auto)
- with th_ready show False by (unfold readys_def eq_waiting, 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 eq_cp:
- assumes neq_th: "th' \<noteq> th"
- shows "cp 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')"
- proof(unfold tRAG_kept, rule f_image_eq)
- fix a
- 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
- from ancestors_Field[OF 2(2)]
- and that show ?thesis by (unfold tRAG_alt_def, auto)
- qed auto
- have neq_th_a: "th_a \<noteq> th"
- proof -
- find_theorems readys subtree s'
- 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
- 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"
- by (unfold eq_a, simp)
- qed
- thus ?thesis by (unfold cp_alt_def1, simp)
-qed
-
-end
-
-end
-