--- /dev/null
+include "cahpter9.ma".
+
+(* bisimulation *)
+definition cofinal ≝ λS.λp:(pre S)×(pre S).
+ \snd (\fst p) = \snd (\snd p).
+
+theorem equiv_sem: ∀S:DeqSet.∀e1,e2:pre S.
+ \sem{e1} =1 \sem{e2} ↔ ∀w.cofinal ? 〈moves ? w e1,moves ? w e2〉.
+#S #e1 #e2 %
+[#same_sem #w
+ cut (∀b1,b2. iff (b1 = true) (b2 = true) → (b1 = b2))
+ [* * // * #H1 #H2 [@sym_eq @H1 //| @H2 //]]
+ #Hcut @Hcut @iff_trans [|@decidable_sem]
+ @iff_trans [|@same_sem] @iff_sym @decidable_sem
+|#H #w1 @iff_trans [||@decidable_sem] <H @iff_sym @decidable_sem]
+qed.
+
+definition occ ≝ λS.λe1,e2:pre S.
+ unique_append ? (occur S (|\fst e1|)) (occur S (|\fst e2|)).
+
+lemma occ_enough: ∀S.∀e1,e2:pre S.
+(∀w.(sublist S w (occ S e1 e2))→ cofinal ? 〈moves ? w e1,moves ? w e2〉)
+ →∀w.cofinal ? 〈moves ? w e1,moves ? w e2〉.
+#S #e1 #e2 #H #w
+cases (decidable_sublist S w (occ S e1 e2)) [@H] -H #H
+ >to_pit [2: @(not_to_not … H) #H1 #a #memba @sublist_unique_append_l1 @H1 //]
+ >to_pit [2: @(not_to_not … H) #H1 #a #memba @sublist_unique_append_l2 @H1 //]
+ //
+qed.
+
+lemma equiv_sem_occ: ∀S.∀e1,e2:pre S.
+(∀w.(sublist S w (occ S e1 e2))→ cofinal ? 〈moves ? w e1,moves ? w e2〉)
+→ \sem{e1}=1\sem{e2}.
+#S #e1 #e2 #H @(proj2 … (equiv_sem …)) @occ_enough #w @H
+qed.
+
+definition sons ≝ λS:DeqSet.λl:list S.λp:(pre S)×(pre S).
+ map ?? (λa.〈move S a (\fst (\fst p)),move S a (\fst (\snd p))〉) l.
+
+lemma memb_sons: ∀S,l.∀p,q:(pre S)×(pre S). memb ? p (sons ? l q) = true →
+ ∃a.(move ? a (\fst (\fst q)) = \fst p ∧
+ move ? a (\fst (\snd q)) = \snd p).
+#S #l elim l [#p #q normalize in ⊢ (%→?); #abs @False_ind /2/]
+#a #tl #Hind #p #q #H cases (orb_true_l … H) -H
+ [#H @(ex_intro … a) >(\P H) /2/ |#H @Hind @H]
+qed.
+
+definition is_bisim ≝ λS:DeqSet.λl:list ?.λalpha:list S.
+ ∀p:(pre S)×(pre S). memb ? p l = true → cofinal ? p ∧ (sublist ? (sons ? alpha p) l).
+
+lemma bisim_to_sem: ∀S:DeqSet.∀l:list ?.∀e1,e2: pre S.
+ is_bisim S l (occ S e1 e2) → memb ? 〈e1,e2〉 l = true → \sem{e1}=1\sem{e2}.
+#S #l #e1 #e2 #Hbisim #Hmemb @equiv_sem_occ
+#w #Hsub @(proj1 … (Hbisim 〈moves S w e1,moves S w e2〉 ?))
+lapply Hsub @(list_elim_left … w) [//]
+#a #w1 #Hind #Hsub >moves_left >moves_left @(proj2 …(Hbisim …(Hind ?)))
+ [#x #Hx @Hsub @memb_append_l1 //
+ |cut (memb S a (occ S e1 e2) = true) [@Hsub @memb_append_l2 //] #occa
+ @(memb_map … occa)
+ ]
+qed.
+
+(* the algorithm *)
+let rec bisim S l n (frontier,visited: list ?) on n ≝
+ match n with
+ [ O ⇒ 〈false,visited〉 (* assert false *)
+ | S m ⇒
+ match frontier with
+ [ nil ⇒ 〈true,visited〉
+ | cons hd tl ⇒
+ if beqb (\snd (\fst hd)) (\snd (\snd hd)) then
+ bisim S l m (unique_append ? (filter ? (λx.notb (memb ? x (hd::visited)))
+ (sons S l hd)) tl) (hd::visited)
+ else 〈false,visited〉
+ ]
+ ].
+
+lemma unfold_bisim: ∀S,l,n.∀frontier,visited: list ?.
+ bisim S l n frontier visited =
+ match n with
+ [ O ⇒ 〈false,visited〉 (* assert false *)
+ | S m ⇒
+ match frontier with
+ [ nil ⇒ 〈true,visited〉
+ | cons hd tl ⇒
+ if beqb (\snd (\fst hd)) (\snd (\snd hd)) then
+ bisim S l m (unique_append ? (filter ? (λx.notb(memb ? x (hd::visited)))
+ (sons S l hd)) tl) (hd::visited)
+ else 〈false,visited〉
+ ]
+ ].
+#S #l #n cases n // qed.
+
+lemma bisim_never: ∀S,l.∀frontier,visited: list ?.
+ bisim S l O frontier visited = 〈false,visited〉.
+#frontier #visited >unfold_bisim //
+qed.
+
+lemma bisim_end: ∀Sig,l,m.∀visited: list ?.
+ bisim Sig l (S m) [] visited = 〈true,visited〉.
+#n #visisted >unfold_bisim //
+qed.
+
+lemma bisim_step_true: ∀Sig,l,m.∀p.∀frontier,visited: list ?.
+beqb (\snd (\fst p)) (\snd (\snd p)) = true →
+ bisim Sig l (S m) (p::frontier) visited =
+ bisim Sig l m (unique_append ? (filter ? (λx.notb(memb ? x (p::visited)))
+ (sons Sig l p)) frontier) (p::visited).
+#Sig #l #m #p #frontier #visited #test >unfold_bisim normalize nodelta >test //
+qed.
+
+lemma bisim_step_false: ∀Sig,l,m.∀p.∀frontier,visited: list ?.
+beqb (\snd (\fst p)) (\snd (\snd p)) = false →
+ bisim Sig l (S m) (p::frontier) visited = 〈false,visited〉.
+#Sig #l #m #p #frontier #visited #test >unfold_bisim normalize nodelta >test //
+qed.
+
+lemma notb_eq_true_l: ∀b. notb b = true → b = false.
+#b cases b normalize //
+qed.
+
+let rec pitem_enum S (i:re S) on i ≝
+ match i with
+ [ z ⇒ [pz S]
+ | e ⇒ [pe S]
+ | s y ⇒ [ps S y; pp S y]
+ | o i1 i2 ⇒ compose ??? (po S) (pitem_enum S i1) (pitem_enum S i2)
+ | c i1 i2 ⇒ compose ??? (pc S) (pitem_enum S i1) (pitem_enum S i2)
+ | k i ⇒ map ?? (pk S) (pitem_enum S i)
+ ].
+
+lemma pitem_enum_complete : ∀S.∀i:pitem S.
+ memb (DeqItem S) i (pitem_enum S (|i|)) = true.
+#S #i elim i
+ [1,2://
+ |3,4:#c normalize >(\b (refl … c)) //
+ |5,6:#i1 #i2 #Hind1 #Hind2 @(memb_compose (DeqItem S) (DeqItem S)) //
+ |#i #Hind @(memb_map (DeqItem S)) //
+ ]
+qed.
+
+definition pre_enum ≝ λS.λi:re S.
+ compose ??? (λi,b.〈i,b〉) (pitem_enum S i) [true;false].
+
+lemma pre_enum_complete : ∀S.∀e:pre S.
+ memb ? e (pre_enum S (|\fst e|)) = true.
+#S * #i #b @(memb_compose (DeqItem S) DeqBool ? (λi,b.〈i,b〉))
+// cases b normalize //
+qed.
+
+definition space_enum ≝ λS.λi1,i2:re S.
+ compose ??? (λe1,e2.〈e1,e2〉) (pre_enum S i1) (pre_enum S i2).
+
+lemma space_enum_complete : ∀S.∀e1,e2: pre S.
+ memb ? 〈e1,e2〉 (space_enum S (|\fst e1|) (|\fst e2|)) = true.
+#S #e1 #e2 @(memb_compose … (λi,b.〈i,b〉))
+// qed.
+
+definition all_reachable ≝ λS.λe1,e2:pre S.λl: list ?.
+uniqueb ? l = true ∧
+ ∀p. memb ? p l = true →
+ ∃w.(moves S w e1 = \fst p) ∧ (moves S w e2 = \snd p).
+
+definition disjoint ≝ λS:DeqSet.λl1,l2.
+ ∀p:S. memb S p l1 = true → memb S p l2 = false.
+
+lemma bisim_correct: ∀S.∀e1,e2:pre S.\sem{e1}=1\sem{e2} →
+ ∀l,n.∀frontier,visited:list ((pre S)×(pre S)).
+ |space_enum S (|\fst e1|) (|\fst e2|)| < n + |visited|→
+ all_reachable S e1 e2 visited →
+ all_reachable S e1 e2 frontier →
+ disjoint ? frontier visited →
+ \fst (bisim S l n frontier visited) = true.
+#Sig #e1 #e2 #same #l #n elim n
+ [#frontier #visited #abs * #unique #H @False_ind @(absurd … abs)
+ @le_to_not_lt @sublist_length // * #e11 #e21 #membp
+ cut ((|\fst e11| = |\fst e1|) ∧ (|\fst e21| = |\fst e2|))
+ [|* #H1 #H2 <H1 <H2 @space_enum_complete]
+ cases (H … membp) #w * #we1 #we2 <we1 <we2 % >same_kernel_moves //
+ |#m #HI * [#visited #vinv #finv >bisim_end //]
+ #p #front_tl #visited #Hn * #u_visited #r_visited * #u_frontier #r_frontier
+ #disjoint
+ cut (∃w.(moves ? w e1 = \fst p) ∧ (moves ? w e2 = \snd p))
+ [@(r_frontier … (memb_hd … ))] #rp
+ cut (beqb (\snd (\fst p)) (\snd (\snd p)) = true)
+ [cases rp #w * #fstp #sndp <fstp <sndp @(\b ?)
+ @(proj1 … (equiv_sem … )) @same] #ptest
+ >(bisim_step_true … ptest) @HI -HI
+ [<plus_n_Sm //
+ |% [whd in ⊢ (??%?); >(disjoint … (memb_hd …)) whd in ⊢ (??%?); //
+ |#p1 #H (cases (orb_true_l … H)) [#eqp >(\P eqp) // |@r_visited]
+ ]
+ |whd % [@unique_append_unique @(andb_true_r … u_frontier)]
+ @unique_append_elim #q #H
+ [cases (memb_sons … (memb_filter_memb … H)) -H
+ #a * #m1 #m2 cases rp #w1 * #mw1 #mw2 @(ex_intro … (w1@[a]))
+ >moves_left >moves_left >mw1 >mw2 >m1 >m2 % //
+ |@r_frontier @memb_cons //
+ ]
+ |@unique_append_elim #q #H
+ [@injective_notb @(filter_true … H)
+ |cut ((q==p) = false)
+ [|#Hpq whd in ⊢ (??%?); >Hpq @disjoint @memb_cons //]
+ cases (andb_true … u_frontier) #notp #_ @(\bf ?)
+ @(not_to_not … not_eq_true_false) #eqqp <notp <eqqp >H //
+ ]
+ ]
+ ]
+qed.
+
+definition all_true ≝ λS.λl.∀p:(pre S) × (pre S). memb ? p l = true →
+ (beqb (\snd (\fst p)) (\snd (\snd p)) = true).
+
+definition sub_sons ≝ λS,l,l1,l2.∀x:(pre S) × (pre S).
+memb ? x l1 = true → sublist ? (sons ? l x) l2.
+
+lemma bisim_complete:
+ ∀S,l,n.∀frontier,visited,visited_res:list ?.
+ all_true S visited →
+ sub_sons S l visited (frontier@visited) →
+ bisim S l n frontier visited = 〈true,visited_res〉 →
+ is_bisim S visited_res l ∧ sublist ? (frontier@visited) visited_res.
+#S #l #n elim n
+ [#fron #vis #vis_res #_ #_ >bisim_never #H destruct
+ |#m #Hind *
+ [(* case empty frontier *)
+ -Hind #vis #vis_res #allv #H normalize in ⊢ (%→?);
+ #H1 destruct % #p
+ [#membp % [@(\P ?) @allv //| @H //]|#H1 @H1]
+ |#hd cases (true_or_false (beqb (\snd (\fst hd)) (\snd (\snd hd))))
+ [|(* case head of the frontier is non ok (absurd) *)
+ #H #tl #vis #vis_res #allv >(bisim_step_false … H) #_ #H1 destruct]
+ (* frontier = hd:: tl and hd is ok *)
+ #H #tl #visited #visited_res #allv >(bisim_step_true … H)
+ (* new_visited = hd::visited are all ok *)
+ cut (all_true S (hd::visited))
+ [#p #H1 cases (orb_true_l … H1) [#eqp >(\P eqp) @H |@allv]]
+ (* we now exploit the induction hypothesis *)
+ #allh #subH #bisim cases (Hind … allh … bisim) -bisim -Hind
+ [#H1 #H2 % // #p #membp @H2 -H2 cases (memb_append … membp) -membp #membp
+ [cases (orb_true_l … membp) -membp #membp
+ [@memb_append_l2 >(\P membp) @memb_hd
+ |@memb_append_l1 @sublist_unique_append_l2 //
+ ]
+ |@memb_append_l2 @memb_cons //
+ ]
+ |(* the only thing left to prove is the sub_sons invariant *)
+ #x #membx cases (orb_true_l … membx)
+ [(* case x = hd *)
+ #eqhdx <(\P eqhdx) #xa #membxa
+ (* xa is a son of x; we must distinguish the case xa
+ was already visited form the case xa is new *)
+ cases (true_or_false … (memb ? xa (x::visited)))
+ [(* xa visited - trivial *) #membxa @memb_append_l2 //
+ |(* xa new *) #membxa @memb_append_l1 @sublist_unique_append_l1 @memb_filter_l
+ [>membxa //|//]
+ ]
+ |(* case x in visited *)
+ #H1 #xa #membxa cases (memb_append … (subH x … H1 … membxa))
+ [#H2 (cases (orb_true_l … H2))
+ [#H3 @memb_append_l2 <(\P H3) @memb_hd
+ |#H3 @memb_append_l1 @sublist_unique_append_l2 @H3
+ ]
+ |#H2 @memb_append_l2 @memb_cons @H2
+ ]
+ ]
+ ]
+ ]
+qed.
+
+definition equiv ≝ λSig.λre1,re2:re Sig.
+ let e1 ≝ •(blank ? re1) in
+ let e2 ≝ •(blank ? re2) in
+ let n ≝ S (length ? (space_enum Sig (|\fst e1|) (|\fst e2|))) in
+ let sig ≝ (occ Sig e1 e2) in
+ (bisim ? sig n [〈e1,e2〉] []).
+
+theorem euqiv_sem : ∀Sig.∀e1,e2:re Sig.
+ \fst (equiv ? e1 e2) = true ↔ \sem{e1} =1 \sem{e2}.
+#Sig #re1 #re2 %
+ [#H @eqP_trans [|@eqP_sym @re_embedding] @eqP_trans [||@re_embedding]
+ cut (equiv ? re1 re2 = 〈true,\snd (equiv ? re1 re2)〉)
+ [<H //] #Hcut
+ cases (bisim_complete … Hcut)
+ [2,3: #p whd in ⊢ ((??%?)→?); #abs @False_ind /2/]
+ #Hbisim #Hsub @(bisim_to_sem … Hbisim)
+ @Hsub @memb_hd
+ |#H @(bisim_correct ? (•(blank ? re1)) (•(blank ? re2)))
+ [@eqP_trans [|@re_embedding] @eqP_trans [|@H] @eqP_sym @re_embedding
+ |//
+ |% // #p whd in ⊢ ((??%?)→?); #abs @False_ind /2/
+ |% // #p #H >(memb_single … H) @(ex_intro … ϵ) /2/
+ |#p #_ normalize //
+ ]
+ ]
+qed.
+
+lemma eqbnat_true : ∀n,m. eqbnat n m = true ↔ n = m.
+#n #m % [@eqbnat_true_to_eq | @eq_to_eqbnat_true]
+qed.
+
+definition DeqNat ≝ mk_DeqSet nat eqbnat eqbnat_true.
+
+definition a ≝ s DeqNat O.
+definition b ≝ s DeqNat (S O).
+definition c ≝ s DeqNat (S (S O)).
+
+definition exp1 ≝ ((a·b)^*·a).
+definition exp2 ≝ a·(b·a)^*.
+definition exp4 ≝ (b·a)^*.
+
+definition exp6 ≝ a·(a ·a ·b^* + b^* ).
+definition exp7 ≝ a · a^* · b^*.
+
+definition exp8 ≝ a·a·a·a·a·a·a·a·(a^* ).
+definition exp9 ≝ (a·a·a + a·a·a·a·a)^*.
+
+example ex1 : \fst (equiv ? (exp8+exp9) exp9) = true.
+normalize // qed.
+
+
+
+
+
+
+
]
qed.
-(* bisimulation *)
-definition cofinal ≝ λS.λp:(pre S)×(pre S).
- \snd (\fst p) = \snd (\snd p).
-
-theorem equiv_sem: ∀S:DeqSet.∀e1,e2:pre S.
- \sem{e1} =1 \sem{e2} ↔ ∀w.cofinal ? 〈moves ? w e1,moves ? w e2〉.
-#S #e1 #e2 %
-[#same_sem #w
- cut (∀b1,b2. iff (b1 = true) (b2 = true) → (b1 = b2))
- [* * // * #H1 #H2 [@sym_eq @H1 //| @H2 //]]
- #Hcut @Hcut @iff_trans [|@decidable_sem]
- @iff_trans [|@same_sem] @iff_sym @decidable_sem
-|#H #w1 @iff_trans [||@decidable_sem] <H @iff_sym @decidable_sem]
-qed.
-
-definition occ ≝ λS.λe1,e2:pre S.
- unique_append ? (occur S (|\fst e1|)) (occur S (|\fst e2|)).
-
-lemma occ_enough: ∀S.∀e1,e2:pre S.
-(∀w.(sublist S w (occ S e1 e2))→ cofinal ? 〈moves ? w e1,moves ? w e2〉)
- →∀w.cofinal ? 〈moves ? w e1,moves ? w e2〉.
-#S #e1 #e2 #H #w
-cases (decidable_sublist S w (occ S e1 e2)) [@H] -H #H
- >to_pit [2: @(not_to_not … H) #H1 #a #memba @sublist_unique_append_l1 @H1 //]
- >to_pit [2: @(not_to_not … H) #H1 #a #memba @sublist_unique_append_l2 @H1 //]
- //
-qed.
-
-lemma equiv_sem_occ: ∀S.∀e1,e2:pre S.
-(∀w.(sublist S w (occ S e1 e2))→ cofinal ? 〈moves ? w e1,moves ? w e2〉)
-→ \sem{e1}=1\sem{e2}.
-#S #e1 #e2 #H @(proj2 … (equiv_sem …)) @occ_enough #w @H
-qed.
-
-definition sons ≝ λS:DeqSet.λl:list S.λp:(pre S)×(pre S).
- map ?? (λa.〈move S a (\fst (\fst p)),move S a (\fst (\snd p))〉) l.
-
-lemma memb_sons: ∀S,l.∀p,q:(pre S)×(pre S). memb ? p (sons ? l q) = true →
- ∃a.(move ? a (\fst (\fst q)) = \fst p ∧
- move ? a (\fst (\snd q)) = \snd p).
-#S #l elim l [#p #q normalize in ⊢ (%→?); #abs @False_ind /2/]
-#a #tl #Hind #p #q #H cases (orb_true_l … H) -H
- [#H @(ex_intro … a) >(\P H) /2/ |#H @Hind @H]
-qed.
-
-definition is_bisim ≝ λS:DeqSet.λl:list ?.λalpha:list S.
- ∀p:(pre S)×(pre S). memb ? p l = true → cofinal ? p ∧ (sublist ? (sons ? alpha p) l).
-
-lemma bisim_to_sem: ∀S:DeqSet.∀l:list ?.∀e1,e2: pre S.
- is_bisim S l (occ S e1 e2) → memb ? 〈e1,e2〉 l = true → \sem{e1}=1\sem{e2}.
-#S #l #e1 #e2 #Hbisim #Hmemb @equiv_sem_occ
-#w #Hsub @(proj1 … (Hbisim 〈moves S w e1,moves S w e2〉 ?))
-lapply Hsub @(list_elim_left … w) [//]
-#a #w1 #Hind #Hsub >moves_left >moves_left @(proj2 …(Hbisim …(Hind ?)))
- [#x #Hx @Hsub @memb_append_l1 //
- |cut (memb S a (occ S e1 e2) = true) [@Hsub @memb_append_l2 //] #occa
- @(memb_map … occa)
- ]
-qed.
-
-(* the algorithm *)
-let rec bisim S l n (frontier,visited: list ?) on n ≝
- match n with
- [ O ⇒ 〈false,visited〉 (* assert false *)
- | S m ⇒
- match frontier with
- [ nil ⇒ 〈true,visited〉
- | cons hd tl ⇒
- if beqb (\snd (\fst hd)) (\snd (\snd hd)) then
- bisim S l m (unique_append ? (filter ? (λx.notb (memb ? x (hd::visited)))
- (sons S l hd)) tl) (hd::visited)
- else 〈false,visited〉
- ]
- ].
-
-lemma unfold_bisim: ∀S,l,n.∀frontier,visited: list ?.
- bisim S l n frontier visited =
- match n with
- [ O ⇒ 〈false,visited〉 (* assert false *)
- | S m ⇒
- match frontier with
- [ nil ⇒ 〈true,visited〉
- | cons hd tl ⇒
- if beqb (\snd (\fst hd)) (\snd (\snd hd)) then
- bisim S l m (unique_append ? (filter ? (λx.notb(memb ? x (hd::visited)))
- (sons S l hd)) tl) (hd::visited)
- else 〈false,visited〉
- ]
- ].
-#S #l #n cases n // qed.
-
-lemma bisim_never: ∀S,l.∀frontier,visited: list ?.
- bisim S l O frontier visited = 〈false,visited〉.
-#frontier #visited >unfold_bisim //
-qed.
-
-lemma bisim_end: ∀Sig,l,m.∀visited: list ?.
- bisim Sig l (S m) [] visited = 〈true,visited〉.
-#n #visisted >unfold_bisim //
-qed.
-
-lemma bisim_step_true: ∀Sig,l,m.∀p.∀frontier,visited: list ?.
-beqb (\snd (\fst p)) (\snd (\snd p)) = true →
- bisim Sig l (S m) (p::frontier) visited =
- bisim Sig l m (unique_append ? (filter ? (λx.notb(memb ? x (p::visited)))
- (sons Sig l p)) frontier) (p::visited).
-#Sig #l #m #p #frontier #visited #test >unfold_bisim normalize nodelta >test //
-qed.
-
-lemma bisim_step_false: ∀Sig,l,m.∀p.∀frontier,visited: list ?.
-beqb (\snd (\fst p)) (\snd (\snd p)) = false →
- bisim Sig l (S m) (p::frontier) visited = 〈false,visited〉.
-#Sig #l #m #p #frontier #visited #test >unfold_bisim normalize nodelta >test //
-qed.
-
-lemma notb_eq_true_l: ∀b. notb b = true → b = false.
-#b cases b normalize //
-qed.
-
-let rec pitem_enum S (i:re S) on i ≝
- match i with
- [ z ⇒ [pz S]
- | e ⇒ [pe S]
- | s y ⇒ [ps S y; pp S y]
- | o i1 i2 ⇒ compose ??? (po S) (pitem_enum S i1) (pitem_enum S i2)
- | c i1 i2 ⇒ compose ??? (pc S) (pitem_enum S i1) (pitem_enum S i2)
- | k i ⇒ map ?? (pk S) (pitem_enum S i)
- ].
-
-lemma pitem_enum_complete : ∀S.∀i:pitem S.
- memb (DeqItem S) i (pitem_enum S (|i|)) = true.
-#S #i elim i
- [1,2://
- |3,4:#c normalize >(\b (refl … c)) //
- |5,6:#i1 #i2 #Hind1 #Hind2 @(memb_compose (DeqItem S) (DeqItem S)) //
- |#i #Hind @(memb_map (DeqItem S)) //
- ]
-qed.
-
-definition pre_enum ≝ λS.λi:re S.
- compose ??? (λi,b.〈i,b〉) (pitem_enum S i) [true;false].
-
-lemma pre_enum_complete : ∀S.∀e:pre S.
- memb ? e (pre_enum S (|\fst e|)) = true.
-#S * #i #b @(memb_compose (DeqItem S) DeqBool ? (λi,b.〈i,b〉))
-// cases b normalize //
-qed.
-
-definition space_enum ≝ λS.λi1,i2:re S.
- compose ??? (λe1,e2.〈e1,e2〉) (pre_enum S i1) (pre_enum S i2).
-
-lemma space_enum_complete : ∀S.∀e1,e2: pre S.
- memb ? 〈e1,e2〉 (space_enum S (|\fst e1|) (|\fst e2|)) = true.
-#S #e1 #e2 @(memb_compose … (λi,b.〈i,b〉))
-// qed.
-
-definition all_reachable ≝ λS.λe1,e2:pre S.λl: list ?.
-uniqueb ? l = true ∧
- ∀p. memb ? p l = true →
- ∃w.(moves S w e1 = \fst p) ∧ (moves S w e2 = \snd p).
-
-definition disjoint ≝ λS:DeqSet.λl1,l2.
- ∀p:S. memb S p l1 = true → memb S p l2 = false.
-
-lemma bisim_correct: ∀S.∀e1,e2:pre S.\sem{e1}=1\sem{e2} →
- ∀l,n.∀frontier,visited:list ((pre S)×(pre S)).
- |space_enum S (|\fst e1|) (|\fst e2|)| < n + |visited|→
- all_reachable S e1 e2 visited →
- all_reachable S e1 e2 frontier →
- disjoint ? frontier visited →
- \fst (bisim S l n frontier visited) = true.
-#Sig #e1 #e2 #same #l #n elim n
- [#frontier #visited #abs * #unique #H @False_ind @(absurd … abs)
- @le_to_not_lt @sublist_length // * #e11 #e21 #membp
- cut ((|\fst e11| = |\fst e1|) ∧ (|\fst e21| = |\fst e2|))
- [|* #H1 #H2 <H1 <H2 @space_enum_complete]
- cases (H … membp) #w * #we1 #we2 <we1 <we2 % >same_kernel_moves //
- |#m #HI * [#visited #vinv #finv >bisim_end //]
- #p #front_tl #visited #Hn * #u_visited #r_visited * #u_frontier #r_frontier
- #disjoint
- cut (∃w.(moves ? w e1 = \fst p) ∧ (moves ? w e2 = \snd p))
- [@(r_frontier … (memb_hd … ))] #rp
- cut (beqb (\snd (\fst p)) (\snd (\snd p)) = true)
- [cases rp #w * #fstp #sndp <fstp <sndp @(\b ?)
- @(proj1 … (equiv_sem … )) @same] #ptest
- >(bisim_step_true … ptest) @HI -HI
- [<plus_n_Sm //
- |% [whd in ⊢ (??%?); >(disjoint … (memb_hd …)) whd in ⊢ (??%?); //
- |#p1 #H (cases (orb_true_l … H)) [#eqp >(\P eqp) // |@r_visited]
- ]
- |whd % [@unique_append_unique @(andb_true_r … u_frontier)]
- @unique_append_elim #q #H
- [cases (memb_sons … (memb_filter_memb … H)) -H
- #a * #m1 #m2 cases rp #w1 * #mw1 #mw2 @(ex_intro … (w1@[a]))
- >moves_left >moves_left >mw1 >mw2 >m1 >m2 % //
- |@r_frontier @memb_cons //
- ]
- |@unique_append_elim #q #H
- [@injective_notb @(filter_true … H)
- |cut ((q==p) = false)
- [|#Hpq whd in ⊢ (??%?); >Hpq @disjoint @memb_cons //]
- cases (andb_true … u_frontier) #notp #_ @(\bf ?)
- @(not_to_not … not_eq_true_false) #eqqp <notp <eqqp >H //
- ]
- ]
- ]
-qed.
-
-definition all_true ≝ λS.λl.∀p:(pre S) × (pre S). memb ? p l = true →
- (beqb (\snd (\fst p)) (\snd (\snd p)) = true).
-
-definition sub_sons ≝ λS,l,l1,l2.∀x:(pre S) × (pre S).
-memb ? x l1 = true → sublist ? (sons ? l x) l2.
-
-lemma bisim_complete:
- ∀S,l,n.∀frontier,visited,visited_res:list ?.
- all_true S visited →
- sub_sons S l visited (frontier@visited) →
- bisim S l n frontier visited = 〈true,visited_res〉 →
- is_bisim S visited_res l ∧ sublist ? (frontier@visited) visited_res.
-#S #l #n elim n
- [#fron #vis #vis_res #_ #_ >bisim_never #H destruct
- |#m #Hind *
- [(* case empty frontier *)
- -Hind #vis #vis_res #allv #H normalize in ⊢ (%→?);
- #H1 destruct % #p
- [#membp % [@(\P ?) @allv //| @H //]|#H1 @H1]
- |#hd cases (true_or_false (beqb (\snd (\fst hd)) (\snd (\snd hd))))
- [|(* case head of the frontier is non ok (absurd) *)
- #H #tl #vis #vis_res #allv >(bisim_step_false … H) #_ #H1 destruct]
- (* frontier = hd:: tl and hd is ok *)
- #H #tl #visited #visited_res #allv >(bisim_step_true … H)
- (* new_visited = hd::visited are all ok *)
- cut (all_true S (hd::visited))
- [#p #H1 cases (orb_true_l … H1) [#eqp >(\P eqp) @H |@allv]]
- (* we now exploit the induction hypothesis *)
- #allh #subH #bisim cases (Hind … allh … bisim) -bisim -Hind
- [#H1 #H2 % // #p #membp @H2 -H2 cases (memb_append … membp) -membp #membp
- [cases (orb_true_l … membp) -membp #membp
- [@memb_append_l2 >(\P membp) @memb_hd
- |@memb_append_l1 @sublist_unique_append_l2 //
- ]
- |@memb_append_l2 @memb_cons //
- ]
- |(* the only thing left to prove is the sub_sons invariant *)
- #x #membx cases (orb_true_l … membx)
- [(* case x = hd *)
- #eqhdx <(\P eqhdx) #xa #membxa
- (* xa is a son of x; we must distinguish the case xa
- was already visited form the case xa is new *)
- cases (true_or_false … (memb ? xa (x::visited)))
- [(* xa visited - trivial *) #membxa @memb_append_l2 //
- |(* xa new *) #membxa @memb_append_l1 @sublist_unique_append_l1 @memb_filter_l
- [>membxa //|//]
- ]
- |(* case x in visited *)
- #H1 #xa #membxa cases (memb_append … (subH x … H1 … membxa))
- [#H2 (cases (orb_true_l … H2))
- [#H3 @memb_append_l2 <(\P H3) @memb_hd
- |#H3 @memb_append_l1 @sublist_unique_append_l2 @H3
- ]
- |#H2 @memb_append_l2 @memb_cons @H2
- ]
- ]
- ]
- ]
-qed.
-
-definition equiv ≝ λSig.λre1,re2:re Sig.
- let e1 ≝ •(blank ? re1) in
- let e2 ≝ •(blank ? re2) in
- let n ≝ S (length ? (space_enum Sig (|\fst e1|) (|\fst e2|))) in
- let sig ≝ (occ Sig e1 e2) in
- (bisim ? sig n [〈e1,e2〉] []).
-
-theorem euqiv_sem : ∀Sig.∀e1,e2:re Sig.
- \fst (equiv ? e1 e2) = true ↔ \sem{e1} =1 \sem{e2}.
-#Sig #re1 #re2 %
- [#H @eqP_trans [|@eqP_sym @re_embedding] @eqP_trans [||@re_embedding]
- cut (equiv ? re1 re2 = 〈true,\snd (equiv ? re1 re2)〉)
- [<H //] #Hcut
- cases (bisim_complete … Hcut)
- [2,3: #p whd in ⊢ ((??%?)→?); #abs @False_ind /2/]
- #Hbisim #Hsub @(bisim_to_sem … Hbisim)
- @Hsub @memb_hd
- |#H @(bisim_correct ? (•(blank ? re1)) (•(blank ? re2)))
- [@eqP_trans [|@re_embedding] @eqP_trans [|@H] @eqP_sym @re_embedding
- |//
- |% // #p whd in ⊢ ((??%?)→?); #abs @False_ind /2/
- |% // #p #H >(memb_single … H) @(ex_intro … ϵ) /2/
- |#p #_ normalize //
- ]
- ]
-qed.
-
-lemma eqbnat_true : ∀n,m. eqbnat n m = true ↔ n = m.
-#n #m % [@eqbnat_true_to_eq | @eq_to_eqbnat_true]
-qed.
-
-definition DeqNat ≝ mk_DeqSet nat eqbnat eqbnat_true.
-
-definition a ≝ s DeqNat O.
-definition b ≝ s DeqNat (S O).
-definition c ≝ s DeqNat (S (S O)).
-
-definition exp1 ≝ ((a·b)^*·a).
-definition exp2 ≝ a·(b·a)^*.
-definition exp4 ≝ (b·a)^*.
-
-definition exp6 ≝ a·(a ·a ·b^* + b^* ).
-definition exp7 ≝ a · a^* · b^*.
-
-definition exp8 ≝ a·a·a·a·a·a·a·a·(a^* ).
-definition exp9 ≝ (a·a·a + a·a·a·a·a)^*.
-
-example ex1 : \fst (equiv ? (exp8+exp9) exp9) = true.
-normalize // qed.
-
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projects / helm.git / commitdiff