\ / GNU General Public License Version 2
V_____________________________________________________________*)
+include "basics/core_notation/fintersects_2.ma".
+include "basics/finset.ma".
include "basics/vectors.ma".
+include "basics/finset.ma".
(* include "basics/relations.ma". *)
(******************************** tape ****************************************)
| cons r0 rs0 ⇒ leftof ? r0 rs0 ]
| cons l0 ls0 ⇒ rightof ? l0 ls0 ] ].
+lemma right_mk_tape :
+ ∀sig,ls,c,rs.(c = None ? → ls = [ ] ∨ rs = [ ]) → right ? (mk_tape sig ls c rs) = rs.
+#sig #ls #c #rs cases c // cases ls
+[ cases rs //
+| #l0 #ls0 #H normalize cases (H (refl ??)) #H1 [ destruct (H1) | >H1 % ] ]
+qed-.
+
+lemma left_mk_tape : ∀sig,ls,c,rs.left ? (mk_tape sig ls c rs) = ls.
+#sig #ls #c #rs cases c // cases ls // cases rs //
+qed.
+
+lemma current_mk_tape : ∀sig,ls,c,rs.current ? (mk_tape sig ls c rs) = c.
+#sig #ls #c #rs cases c // cases ls // cases rs //
+qed.
+
lemma current_to_midtape: ∀sig,t,c. current sig t = Some ? c →
∃ls,rs. t = midtape ? ls c rs.
#sig *
inductive move : Type[0] ≝
| L : move | R : move | N : move.
+
+(*************************** turning moves into a DeqSet **********************)
+
+definition move_eq ≝ λm1,m2:move.
+ match m1 with
+ [R ⇒ match m2 with [R ⇒ true | _ ⇒ false]
+ |L ⇒ match m2 with [L ⇒ true | _ ⇒ false]
+ |N ⇒ match m2 with [N ⇒ true | _ ⇒ false]].
+
+lemma move_eq_true:∀m1,m2.
+ move_eq m1 m2 = true ↔ m1 = m2.
+*
+ [* normalize [% #_ % |2,3: % #H destruct ]
+ |* normalize [1,3: % #H destruct |% #_ % ]
+ |* normalize [1,2: % #H destruct |% #_ % ]
+qed.
+
+definition DeqMove ≝ mk_DeqSet move move_eq move_eq_true.
+
+unification hint 0 ≔ ;
+ X ≟ DeqMove
+(* ---------------------------------------- *) ⊢
+ move ≡ carr X.
+
+unification hint 0 ≔ m1,m2;
+ X ≟ DeqMove
+(* ---------------------------------------- *) ⊢
+ move_eq m1 m2 ≡ eqb X m1 m2.
+
+(************************ turning DeqMove into a FinSet ***********************)
+
+definition move_enum ≝ [L;R;N].
+
+lemma move_enum_unique: uniqueb ? [L;R;N] = true.
+// qed.
+
+lemma move_enum_complete: ∀x:move. memb ? x [L;R;N] = true.
+* // qed.
+
+definition FinMove ≝
+ mk_FinSet DeqMove [L;R;N] move_enum_unique move_enum_complete.
+
+unification hint 0 ≔ ;
+ X ≟ FinMove
+(* ---------------------------------------- *) ⊢
+ move ≡ FinSetcarr X.
(********************************** machine ***********************************)
record TM (sig:FinSet): Type[1] ≝
| N ⇒ t
].
+definition tape_move_mono ≝
+ λsig,t,mv.
+ tape_move sig (tape_write sig t (\fst mv)) (\snd mv).
+
record config (sig,states:FinSet): Type[0] ≝
{ cstate : states;
ctape: tape sig
let 〈news,a,mv〉 ≝ trans sig M 〈cstate ?? c,current_char〉 in
mk_config ?? news (tape_move sig (tape_write ? (ctape ?? c) a) mv).
+(*
+lemma step_eq : ∀sig,M,c.
+ let current_char ≝ current ? (ctape ?? c) in
+ let 〈news,a,mv〉 ≝ trans sig M 〈cstate ?? c,current_char〉 in
+ step sig M c =
+ mk_config ?? news (tape_move sig (tape_write ? (ctape ?? c) a) mv).
+#sig #M #c
+ whd in match (tape_move_mono sig ??);
+*)
+
(******************************** loop ****************************************)
let rec loop (A:Type[0]) n (f:A→A) p a on n ≝
match n with
#k * #outc * #Hloop #Houtc @(ex_intro … k) @(ex_intro … outc)
% [@Hloop |@Hsub @Houtc]
qed.
+
+theorem acc_sem_seq : ∀sig.∀M1,M2:TM sig.∀R1,Rtrue,Rfalse,acc.
+ M1 ⊨ R1 → M2 ⊨ [ acc: Rtrue, Rfalse ] →
+ M1 · M2 ⊨ [ inr … acc: R1 ∘ Rtrue, R1 ∘ Rfalse ].
+#sig #M1 #M2 #R1 #Rtrue #Rfalse #acc #HR1 #HR2 #t
+cases (HR1 t) #k1 * #outc1 * #Hloop1 #HM1
+cases (HR2 (ctape sig (states ? M1) outc1)) #k2 * #outc2 * * #Hloop2
+#HMtrue #HMfalse
+@(ex_intro … (k1+k2)) @(ex_intro … (lift_confR … outc2))
+% [ %
+[@(loop_merge …
+ (loop_lift ??? (lift_confL sig (states sig M1) (states sig M2))
+ (step sig M1) (step sig (seq sig M1 M2))
+ (λc.halt sig M1 (cstate … c))
+ (λc.halt_liftL ?? (halt sig M1) (cstate … c)) … Hloop1))
+ [ * *
+ [ #sl #tl whd in ⊢ (??%? → ?); #Hl %
+ | #sr #tr whd in ⊢ (??%? → ?); #Hr destruct (Hr) ]
+ || #c0 #Hhalt <step_seq_liftL //
+ | #x <p_halt_liftL %
+ |6:cases outc1 #s1 #t1 %
+ |7:@(loop_lift … (initc ?? (ctape … outc1)) … Hloop2)
+ [ * #s2 #t2 %
+ | #c0 #Hhalt <step_seq_liftR // ]
+ |whd in ⊢ (??(???%)?);whd in ⊢ (??%?);
+ generalize in match Hloop1; cases outc1 #sc1 #tc1 #Hloop10
+ >(trans_liftL_true sig M1 M2 ??)
+ [ whd in ⊢ (??%?); whd in ⊢ (???%); //
+ | @(loop_Some ?????? Hloop10) ]
+ ]
+| >(config_expand … outc2) in ⊢ (%→?); whd in ⊢ (??%?→?);
+ #Hqtrue destruct (Hqtrue)
+ @(ex_intro … (ctape ? (FinSum (states ? M1) (states ? M2)) (lift_confL … outc1)))
+ % // >eq_ctape_lift_conf_L >eq_ctape_lift_conf_R /2/ ]
+| >(config_expand … outc2) in ⊢ (%→?); whd in ⊢ (?(??%?)→?); #Hqfalse
+ @(ex_intro … (ctape ? (FinSum (states ? M1) (states ? M2)) (lift_confL … outc1)))
+ % // >eq_ctape_lift_conf_L >eq_ctape_lift_conf_R @HMfalse
+ @(not_to_not … Hqfalse) //
+]
+qed.
+
+lemma acc_sem_seq_app : ∀sig.∀M1,M2:TM sig.∀R1,Rtrue,Rfalse,R2,R3,acc.
+ M1 ⊨ R1 → M2 ⊨ [acc: Rtrue, Rfalse] →
+ (∀t1,t2,t3. R1 t1 t3 → Rtrue t3 t2 → R2 t1 t2) →
+ (∀t1,t2,t3. R1 t1 t3 → Rfalse t3 t2 → R3 t1 t2) →
+ M1 · M2 ⊨ [inr … acc : R2, R3].
+#sig #M1 #M2 #R1 #Rtrue #Rfalse #R2 #R3 #acc
+#HR1 #HRacc #Hsub1 #Hsub2
+#t cases (acc_sem_seq … HR1 HRacc t)
+#k * #outc * * #Hloop #Houtc1 #Houtc2 @(ex_intro … k) @(ex_intro … outc)
+% [% [@Hloop
+ |#H cases (Houtc1 H) #t3 * #Hleft #Hright @Hsub1 // ]
+ |#H cases (Houtc2 H) #t3 * #Hleft #Hright @Hsub2 // ]
+qed.