match (nth src (option sig) v (None ?)) with
[ None ⇒ false
| Some x ⇒ notb (nth dst (DeqOption sig) v (None ?) == None ?) ].
+
+definition mmove_states ≝ initN 2.
+
+definition mmove0 : mmove_states ≝ mk_Sig ?? 0 (leb_true_to_le 1 2 (refl …)).
+definition mmove1 : mmove_states ≝ mk_Sig ?? 1 (leb_true_to_le 2 2 (refl …)).
+
+definition trans_mmove ≝
+ λi,sig,n,D.
+ λp:mmove_states × (Vector (option sig) (S n)).
+ let 〈q,a〉 ≝ p in match (pi1 … q) with
+ [ O ⇒ 〈mmove1,change_vec ? (S n) (null_action ? n) (〈None ?,D〉) i〉
+ | S _ ⇒ 〈mmove1,null_action sig n〉 ].
+
+definition mmove ≝
+ λi,sig,n,D.
+ mk_mTM sig n mmove_states (trans_mmove i sig n D)
+ mmove0 (λq.q == mmove1).
+
+definition Rm_multi ≝
+ λalpha,n,i,D.λt1,t2:Vector ? (S n).
+ t2 = change_vec ? (S n) t1 (tape_move alpha (nth i ? t1 (niltape ?)) D) i.
+
+lemma sem_move_multi :
+ ∀alpha,n,i,D.i ≤ n →
+ mmove i alpha n D ⊨ Rm_multi alpha n i D.
+#alpha #n #i #D #Hin #int %{2}
+%{(mk_mconfig ? mmove_states n mmove1 ?)}
+[| %
+ [ whd in ⊢ (??%?); @eq_f whd in ⊢ (??%?); @eq_f %
+ | whd >tape_move_multi_def
+ <(change_vec_same … (ctapes …) i (niltape ?))
+ >pmap_change <tape_move_multi_def >tape_move_null_action % ] ]
+ qed.
-definition rewind ≝ λsrc,dst,sig,n.parmove src dst sig n L · parmove_step src dst sig n R.
+definition rewind ≝ λsrc,dst,sig,n.
+ parmove src dst sig n L · mmove src sig n R · mmove dst sig n R.
definition R_rewind ≝ λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
(∀x,x0,xs,rs.
src ≠ dst → src < S n → dst < S n →
rewind src dst sig n ⊨ R_rewind src dst sig n.
#src #dst #sig #n #Hneq #Hsrc #Hdst
-check acc_sem_seq_app
-@(sem_seq_app sig n ????? (sem_parmoveL src dst sig n Hneq Hsrc Hdst)
- (accRealize_to_Realize … (sem_parmove_step src dst sig n R Hneq Hsrc Hdst)))
-#ta #tb * #tc * * #HR1 #_ #HR2
+@(sem_seq_app sig n ????? (sem_parmoveL src dst sig n Hneq Hsrc Hdst) ?)
+[| @(sem_seq_app sig n ????? (sem_move_r_multi …) (sem_move_r_multi …)) //
+ @le_S_S_to_le // ]
+#ta #tb * #tc * * #Htc #_ * #td * whd in ⊢ (%→%→?); #Htd #Htb
#x #x0 #xs #rs #Hmidta_src #ls0 #y #y0 #target #rs0 #Hlen #Hmidta_dst
->(HR1 ??? Hmidta_src ls0 y (target@[y0]) rs0 ??) in HR2;
+>(Htc ??? Hmidta_src ls0 y (target@[y0]) rs0 ??) in Htd;
[|>Hmidta_dst //
-|>length_append >length_append >Hlen % ] *
+|>length_append >length_append >Hlen % ] * #_
[ whd in ⊢ (%→?); * #x1 * #x2 * *
>change_vec_commute in ⊢ (%→?); // >nth_change_vec //
cases (reverse sig (xs@[x0])@x::rs)