1 (**************************************************************************)
4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
8 (* ||A|| http://helm.cs.unibo.it *)
10 (* \ / This file is distributed under the terms of the *)
11 (* v GNU General Public License Version 2 *)
13 (**************************************************************************)
15 include "turing/multi_universal/compare.ma".
16 include "turing/multi_universal/par_test.ma".
17 include "turing/multi_universal/moves_2.ma".
19 definition Rtc_multi_true ≝
20 λalpha,test,n,i.λt1,t2:Vector ? (S n).
21 (∃c. current alpha (nth i ? t1 (niltape ?)) = Some ? c ∧ test c = true) ∧ t2 = t1.
23 definition Rtc_multi_false ≝
24 λalpha,test,n,i.λt1,t2:Vector ? (S n).
25 (∀c. current alpha (nth i ? t1 (niltape ?)) = Some ? c → test c = false) ∧ t2 = t1.
27 lemma sem_test_char_multi :
28 ∀alpha,test,n,i.i ≤ n →
29 inject_TM ? (test_char ? test) n i ⊨
30 [ tc_true : Rtc_multi_true alpha test n i, Rtc_multi_false alpha test n i ].
31 #alpha #test #n #i #Hin #int
32 cases (acc_sem_inject … Hin (sem_test_char alpha test) int)
33 #k * #outc * * #Hloop #Htrue #Hfalse %{k} %{outc} % [ %
35 | #Hqtrue lapply (Htrue Hqtrue) * * * #c *
36 #Hcur #Htestc #Hnth_i #Hnth_j %
38 | @(eq_vec … (niltape ?)) #i0 #Hi0
39 cases (decidable_eq_nat i0 i) #Hi0i
41 | @sym_eq @Hnth_j @sym_not_eq // ] ] ]
42 | #Hqfalse lapply (Hfalse Hqfalse) * * #Htestc #Hnth_i #Hnth_j %
44 | @(eq_vec … (niltape ?)) #i0 #Hi0
45 cases (decidable_eq_nat i0 i) #Hi0i
47 | @sym_eq @Hnth_j @sym_not_eq // ] ] ]
50 definition Rm_test_null_true ≝
51 λalpha,n,i.λt1,t2:Vector ? (S n).
52 current alpha (nth i ? t1 (niltape ?)) ≠ None ? ∧ t2 = t1.
54 definition Rm_test_null_false ≝
55 λalpha,n,i.λt1,t2:Vector ? (S n).
56 current alpha (nth i ? t1 (niltape ?)) = None ? ∧ t2 = t1.
58 lemma sem_test_null_multi : ∀alpha,n,i.i ≤ n →
59 inject_TM ? (test_null ?) n i ⊨
60 [ tc_true : Rm_test_null_true alpha n i, Rm_test_null_false alpha n i ].
61 #alpha #n #i #Hin #int
62 cases (acc_sem_inject … Hin (sem_test_null alpha) int)
63 #k * #outc * * #Hloop #Htrue #Hfalse %{k} %{outc} % [ %
65 | #Hqtrue lapply (Htrue Hqtrue) * * #Hcur #Hnth_i #Hnth_j % //
66 @(eq_vec … (niltape ?)) #i0 #Hi0 cases (decidable_eq_nat i0 i) #Hi0i
67 [ >Hi0i @sym_eq @Hnth_i | @sym_eq @Hnth_j @sym_not_eq // ] ]
68 | #Hqfalse lapply (Hfalse Hqfalse) * * #Hcur #Hnth_i #Hnth_j %
70 | @(eq_vec … (niltape ?)) #i0 #Hi0 cases (decidable_eq_nat i0 i) //
71 #Hi0i @sym_eq @Hnth_j @sym_not_eq // ] ]
74 definition match_test ≝ λsrc,dst.λsig:DeqSet.λn.λv:Vector ? n.
75 match (nth src (option sig) v (None ?)) with
77 | Some x ⇒ notb (nth dst (DeqOption sig) v (None ?) == None ?) ].
79 definition mmove_states ≝ initN 2.
81 definition mmove0 : mmove_states ≝ mk_Sig ?? 0 (leb_true_to_le 1 2 (refl …)).
82 definition mmove1 : mmove_states ≝ mk_Sig ?? 1 (leb_true_to_le 2 2 (refl …)).
84 definition trans_mmove ≝
86 λp:mmove_states × (Vector (option sig) (S n)).
87 let 〈q,a〉 ≝ p in match (pi1 … q) with
88 [ O ⇒ 〈mmove1,change_vec ? (S n) (null_action ? n) (〈None ?,D〉) i〉
89 | S _ ⇒ 〈mmove1,null_action sig n〉 ].
93 mk_mTM sig n mmove_states (trans_mmove i sig n D)
94 mmove0 (λq.q == mmove1).
97 λalpha,n,i,D.λt1,t2:Vector ? (S n).
98 t2 = change_vec ? (S n) t1 (tape_move alpha (nth i ? t1 (niltape ?)) D) i.
100 lemma sem_move_multi :
102 mmove i alpha n D ⊨ Rm_multi alpha n i D.
103 #alpha #n #i #D #Hin #int %{2}
104 %{(mk_mconfig ? mmove_states n mmove1 ?)}
106 [ whd in ⊢ (??%?); @eq_f whd in ⊢ (??%?); @eq_f %
107 | whd >tape_move_multi_def
108 <(change_vec_same … (ctapes …) i (niltape ?))
109 >pmap_change <tape_move_multi_def >tape_move_null_action % ] ]
112 definition rewind ≝ λsrc,dst,sig,n.
113 parmove src dst sig n L · mmove src sig n R · mmove dst sig n R.
115 definition R_rewind_strong ≝ λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
117 nth src ? int (niltape ?) = midtape sig (xs@[x0]) x rs →
118 ∀ls0,y,y0,target,rs0.|xs| = |target| →
119 nth dst ? int (niltape ?) = midtape sig (target@y0::ls0) y rs0 →
121 (change_vec ?? int (midtape sig [] x0 (reverse ? xs@x::rs)) src)
122 (midtape sig ls0 y0 (reverse ? target@y::rs0)) dst) ∧
124 nth dst ? int (niltape ?) = midtape sig (xs@[x0]) x rs →
125 ∀ls0,y,y0,target,rs0.|xs| = |target| →
126 nth src ? int (niltape ?) = midtape sig (target@y0::ls0) y rs0 →
128 (change_vec ?? int (midtape sig [] x0 (reverse ? xs@x::rs)) dst)
129 (midtape sig ls0 y0 (reverse ? target@y::rs0)) src) ∧
130 (∀x,rs.nth src ? int (niltape ?) = midtape sig [] x rs →
131 ∀ls0,y,rs0.nth dst ? int (niltape ?) = midtape sig ls0 y rs0 →
133 (∀x,rs.nth dst ? int (niltape ?) = midtape sig [] x rs →
134 ∀ls0,y,rs0.nth src ? int (niltape ?) = midtape sig ls0 y rs0 →
137 definition R_rewind ≝ λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
139 nth src ? int (niltape ?) = midtape sig (xs@[x0]) x rs →
140 ∀ls0,y,y0,target,rs0.|xs| = |target| →
141 nth dst ? int (niltape ?) = midtape sig (target@y0::ls0) y rs0 →
143 (change_vec ?? int (midtape sig [] x0 (reverse ? xs@x::rs)) src)
144 (midtape sig ls0 y0 (reverse ? target@y::rs0)) dst) ∧
145 (∀x,rs.nth src ? int (niltape ?) = midtape sig [] x rs →
146 ∀ls0,y,rs0.nth dst ? int (niltape ?) = midtape sig ls0 y rs0 →
150 theorem accRealize_to_Realize :
151 ∀sig,n.∀M:mTM sig n.∀Rtrue,Rfalse,acc.
152 M ⊨ [ acc: Rtrue, Rfalse ] → M ⊨ Rtrue ∪ Rfalse.
153 #sig #n #M #Rtrue #Rfalse #acc #HR #t
154 cases (HR t) #k * #outc * * #Hloop
155 #Htrue #Hfalse %{k} %{outc} % //
156 cases (true_or_false (cstate sig (states sig n M) n outc == acc)) #Hcase
157 [ % @Htrue @(\P Hcase) | %2 @Hfalse @(\Pf Hcase) ]
161 lemma sem_rewind_strong : ∀src,dst,sig,n.
162 src ≠ dst → src < S n → dst < S n →
163 rewind src dst sig n ⊨ R_rewind_strong src dst sig n.
164 #src #dst #sig #n #Hneq #Hsrc #Hdst
165 @(sem_seq_app sig n ????? (sem_parmoveL src dst sig n Hneq Hsrc Hdst) ?)
166 [| @(sem_seq_app sig n ????? (sem_move_multi … R ?) (sem_move_multi … R ?)) //
168 #ta #tb * #tc * * * #Htc1 #Htc2 #_ * #td * whd in ⊢ (%→%→?); #Htd #Htb % [ % [ %
169 [ #x #x0 #xs #rs #Hmidta_src #ls0 #y #y0 #target #rs0 #Hlen #Hmidta_dst
170 >(Htc1 ??? Hmidta_src ls0 y (target@[y0]) rs0 ??) in Htd;
172 |>length_append >length_append >Hlen % ]
173 >change_vec_commute [|@sym_not_eq //]
174 >change_vec_change_vec
175 >nth_change_vec_neq [|@sym_not_eq //]
176 >nth_change_vec // >reverse_append >reverse_single
177 >reverse_append >reverse_single normalize in match (tape_move ???);
178 >rev_append_def >append_nil #Htd >Htd in Htb;
179 >change_vec_change_vec >nth_change_vec //
180 cases ls0 [|#l1 #ls1] normalize in match (tape_move ???); //
181 | #x #x0 #xs #rs #Hmidta_dst #ls0 #y #y0 #target #rs0 #Hlen #Hmidta_src
182 >(Htc2 ??? Hmidta_dst ls0 y (target@[y0]) rs0 ??) in Htd;
184 |>length_append >length_append >Hlen % ]
185 >change_vec_change_vec
186 >change_vec_commute [|@sym_not_eq //]
188 >reverse_append >reverse_single
189 >reverse_append >reverse_single
190 cases ls0 [|#l1 #ls1] normalize in match (tape_move ???);
191 #Htd >Htd in Htb; >change_vec_change_vec >nth_change_vec //
192 >rev_append_def >change_vec_commute // normalize in match (tape_move ???); // ]
193 | #x #rs #Hmidta_src #ls0 #y #rs0 #Hmidta_dst
194 lapply (Htc1 … Hmidta_src … (refl ??) Hmidta_dst) -Htc1 #Htc >Htc in Htd;
195 >change_vec_commute [|@sym_not_eq //] >change_vec_change_vec
196 >nth_change_vec_neq [|@sym_not_eq //]
197 >nth_change_vec // lapply (refl ? ls0) cases ls0 in ⊢ (???%→%);
198 [ #Hls0 #Htd >Htd in Htb;
199 >nth_change_vec // >change_vec_change_vec
200 whd in match (tape_move ???);whd in match (tape_move ???); <Hmidta_src
201 <Hls0 <Hmidta_dst >change_vec_same >change_vec_same //
202 | #l1 #ls1 #Hls0 #Htd >Htd in Htb;
203 >nth_change_vec // >change_vec_change_vec
204 whd in match (tape_move ???);whd in match (tape_move ???); <Hmidta_src
205 <Hls0 <Hmidta_dst >change_vec_same >change_vec_same //
207 | #x #rs #Hmidta_dst #ls0 #y #rs0 #Hmidta_src
208 lapply (Htc2 … Hmidta_dst … (refl ??) Hmidta_src) -Htc2 #Htc >Htc in Htd;
209 >change_vec_change_vec >change_vec_commute [|@sym_not_eq //]
210 >nth_change_vec // lapply (refl ? ls0) cases ls0 in ⊢ (???%→%);
211 [ #Hls0 destruct (Hls0) #Htd >Htd in Htb;
212 >nth_change_vec // >change_vec_change_vec
213 whd in match (tape_move ???);whd in match (tape_move ???);
214 <Hmidta_src <Hmidta_dst >change_vec_same >change_vec_same //
215 | #l1 #ls1 #Hls0 destruct (Hls0) #Htd >Htd in Htb;
216 >nth_change_vec // >change_vec_change_vec
217 whd in match (tape_move ???); whd in match (tape_move ???); <Hmidta_src
218 <Hmidta_dst >change_vec_same >change_vec_same //
223 lemma sem_rewind : ∀src,dst,sig,n.
224 src ≠ dst → src < S n → dst < S n →
225 rewind src dst sig n ⊨ R_rewind src dst sig n.
226 #src #dst #sig #n #Hneq #Hsrc #Hdst @(Realize_to_Realize … (sem_rewind_strong …)) //
227 #ta #tb * * * #H1 #H2 #H3 #H4 % /2/
230 definition match_step ≝ λsrc,dst,sig,n.
231 compare src dst sig n ·
232 (ifTM ?? (partest sig n (match_test src dst sig ?))
234 (rewind src dst sig n · (inject_TM ? (move_r ?) n dst)))
238 (* we assume the src is a midtape
240 if the dst is out of bounds (outt = int)
241 or dst.right is shorter than src.right (outt.current → None)
242 or src.right is a prefix of dst.right (out = just right of the common prefix) *)
243 definition R_match_step_false ≝
244 λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
246 nth src ? int (niltape ?) = midtape sig ls x xs →
247 ((current sig (nth dst (tape sig) int (niltape sig)) = None ?) ∧ outt = int) ∨
248 (∃ls0,rs0,xs0. nth dst ? int (niltape ?) = midtape sig ls0 x rs0 ∧
251 (change_vec ?? int (mk_tape sig (reverse ? rs0@x::ls) (option_hd ? xs0) (tail ? xs0)) src)
252 (mk_tape ? (reverse ? rs0@x::ls0) (None ?) [ ]) dst) ∨
254 nth dst ? int (niltape ?) = midtape sig ls0 x (xs@rs0) ∧
258 (change_vec ?? int (mk_tape sig (reverse ? xs@x::ls) (None ?) [ ]) src)
259 (mk_tape sig (reverse ? xs@x::ls0) (option_hd ? rs0) (tail ? rs0)) dst).
262 we assume the src is a midtape [ ] s rs
264 then dst.current = Some ? s1
265 and if s ≠ s1 then outt = int.dst.move_right()
267 then int.src.right and int.dst.right have a common prefix
268 and the heads of their suffixes are different
269 and outt = int.dst.move_right().
272 definition R_match_step_true ≝
273 λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
274 ∀s,rs.nth src ? int (niltape ?) = midtape ? [ ] s rs →
275 outt = change_vec ?? int
276 (tape_move_mono … (nth dst ? int (niltape ?)) (〈None ?,R〉)) dst ∧
277 (∃s0.current sig (nth dst (tape sig) int (niltape sig)) = Some ? s0 ∧
279 ∃xs,ci,rs',ls0,cj,rs0.
281 nth dst ? int (niltape ?) = midtape sig ls0 s (xs@cj::rs0) ∧
284 lemma sem_match_step :
285 ∀src,dst,sig,n.src ≠ dst → src < S n → dst < S n →
286 match_step src dst sig n ⊨
287 [ inr ?? (inr ?? (inl … (inr ?? start_nop))) :
288 R_match_step_true src dst sig n,
289 R_match_step_false src dst sig n ].
290 #src #dst #sig #n #Hneq #Hsrc #Hdst
291 @(acc_sem_seq_app sig n … (sem_compare src dst sig n Hneq Hsrc Hdst)
292 (acc_sem_if ? n … (sem_partest sig n (match_test src dst sig ?))
294 (sem_rewind ???? Hneq Hsrc Hdst)
295 (sem_inject … dst (le_S_S_to_le … Hdst) (sem_move_r ? )))
297 [ #ta #tb #tc * lapply (refl ? (current ? (nth src ? ta (niltape ?))))
298 cases (current ? (nth src ? ta (niltape ?))) in ⊢ (???%→%);
299 [ #Hcurta_src #Hcomp #_ * #td * >Hcomp [| % %2 %]
300 whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
301 >nth_current_chars >Hcurta_src normalize in ⊢ (%→?); #H destruct (H)
302 | #s #Hs lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
303 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→%);
304 [ #Hcurta_dst #Hcomp #_ * #td * >Hcomp [| %2 %]
305 whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
306 >nth_current_chars >nth_current_chars >Hs >Hcurta_dst
307 normalize in ⊢ (%→?); #H destruct (H)
309 cases (current_to_midtape … Hs) #ls * #rs #Hmidta_src >Hmidta_src
310 cases (current_to_midtape … Hs0) #ls0 * #rs0 #Hmidta_dst >Hmidta_dst
311 cases (true_or_false (s == s0)) #Hss0
312 [ lapply (\P Hss0) -Hss0 #Hss0 destruct (Hss0)
313 #_ #Hcomp cases (Hcomp ????? (refl ??) (refl ??)) -Hcomp [ *
314 [ * #rs' * #_ #Hcurtc_dst * #td * whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
315 >nth_current_chars >nth_current_chars >Hcurtc_dst
316 cases (current ? (nth src …))
317 [normalize in ⊢ (%→?); #H destruct (H)
318 | #x >nth_change_vec // cases (reverse ? rs0)
319 [ normalize in ⊢ (%→?); #H destruct (H)
320 | #r1 #rs1 normalize in ⊢ (%→?); #H destruct (H) ] ]
321 | * #rs0' * #_ #Hcurtc_src * #td * whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
322 >(?:nth src ? (current_chars ?? tc) (None ?) = None ?)
323 [|>nth_current_chars >Hcurtc_src >nth_change_vec_neq
324 [>nth_change_vec [cases (append ???) // | @Hsrc]
325 |@(not_to_not … Hneq) //
327 normalize in ⊢ (%→?); #H destruct (H) ]
328 | * #xs * #ci * #cj * #rs'' * #rs0' * * * #Hcicj #Hrs #Hrs0
329 #Htc * #td * * #Hmatch #Htd destruct (Htd) * #te * *
330 >Htc >change_vec_commute // >nth_change_vec //
331 >change_vec_commute [|@sym_not_eq //] >nth_change_vec // #Hte #_ #Htb
332 #s' #rs' >Hmidta_src #H destruct (H)
333 lapply (Hte … (refl ??) … (refl ??) (refl ??)) -Hte
334 >change_vec_commute // >change_vec_change_vec
335 >change_vec_commute [|@sym_not_eq //] >change_vec_change_vec #Hte
336 >Hte in Htb; * * #_ >nth_change_vec // #Htb1
337 lapply (Htb1 … (refl ??)) -Htb1 #Htb1 #Htb2 %
338 [ @(eq_vec … (niltape ?)) #i #Hi
339 cases (true_or_false ((dst : DeqNat) == i)) #Hdsti
340 [ <(\P Hdsti) >Htb1 >nth_change_vec // >Hmidta_dst
341 >Hrs0 >reverse_reverse cases xs [|#r1 #rs1] %
342 | <Htb2 [|@(\Pf Hdsti)] >nth_change_vec_neq [| @(\Pf Hdsti)]
343 >Hrs0 >reverse_reverse >nth_change_vec_neq in ⊢ (???%);
344 <Hrs <Hmidta_src [|@(\Pf Hdsti)] >change_vec_same % ]
345 | >Hmidta_dst %{s'} % [%] #_
346 >Hrs0 %{xs} %{ci} %{rs''} %{ls0} %{cj} %{rs0'} % // % //
349 | lapply (\Pf Hss0) -Hss0 #Hss0 #Htc cut (tc = ta)
350 [@Htc % % @(not_to_not ??? Hss0) #H destruct (H) %]
351 -Htc #Htc destruct (Htc) #_ * #td * whd in ⊢ (%→?); * #_
352 #Htd destruct (Htd) * #te * * #_ #Hte * * #_ #Htb1 #Htb2
353 #s1 #rs1 >Hmidta_src #H destruct (H)
354 lapply (Hte … Hmidta_src … Hmidta_dst) -Hte #Hte destruct (Hte) %
355 [ @(eq_vec … (niltape ?)) #i #Hi
356 cases (true_or_false ((dst : DeqNat) == i)) #Hdsti
357 [ <(\P Hdsti) >(Htb1 … Hmidta_dst) >nth_change_vec // >Hmidta_dst
358 cases rs0 [|#r2 #rs2] %
359 | <Htb2 [|@(\Pf Hdsti)] >nth_change_vec_neq [| @(\Pf Hdsti)] % ]
360 | >Hs0 %{s0} % // #H destruct (H) @False_ind cases (Hss0) /2/ ]
364 | #ta #tb #tc * #Hcomp1 #Hcomp2 * #td * * #Htest #Htd destruct (Htd)
365 whd in ⊢ (%→?); #Htb destruct (Htb) #ls #x #xs #Hta_src
366 lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
367 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→?);
368 [ #Hcurta_dst % % % // @Hcomp1 %2 //
369 | #x0 #Hcurta_dst cases (current_to_midtape … Hcurta_dst) -Hcurta_dst
370 #ls0 * #rs0 #Hta_dst cases (true_or_false (x == x0)) #Hxx0
371 [ lapply (\P Hxx0) -Hxx0 #Hxx0 destruct (Hxx0)
372 | >(?:tc=ta) in Htest;
373 [|@Hcomp1 % % >Hta_src >Hta_dst @(not_to_not ??? (\Pf Hxx0)) normalize
374 #Hxx0' destruct (Hxx0') % ]
376 >nth_current_chars >Hta_src >nth_current_chars >Hta_dst
377 whd in ⊢ (??%?→?); #Hfalse destruct (Hfalse) ] -Hcomp1
378 cases (Hcomp2 … Hta_src Hta_dst) [ *
379 [ * #rs' * #Hxs #Hcurtc % %2 %{ls0} %{rs0} %{rs'} %
381 | * #rs0' * #Hxs #Htc %2 >Htc %{ls0} %{rs0'} % // ]
382 | * #xs0 * #ci * #cj * #rs' * #rs0' * * *
383 #Hci #Hxs #Hrs0 #Htc @False_ind
385 >(?:nth src ? (current_chars ?? tc) (None ?) = Some ? ci) in Htest;
386 [|>nth_current_chars >Htc >nth_change_vec_neq [|@(not_to_not … Hneq) //]
388 >(?:nth dst ? (current_chars ?? tc) (None ?) = Some ? cj)
389 [|>nth_current_chars >Htc >nth_change_vec //]
390 normalize #H destruct (H) ] ] ]
393 definition match_m ≝ λsrc,dst,sig,n.
394 whileTM … (match_step src dst sig n)
395 (inr ?? (inr ?? (inl … (inr ?? start_nop)))).
397 definition R_match_m ≝
398 λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
400 nth src ? int (niltape ?) = midtape sig [ ] x rs →
401 (current sig (nth dst (tape sig) int (niltape sig)) = None ? →
402 right ? (nth dst (tape sig) int (niltape sig)) = [ ] → outt = int) ∧
404 nth dst ? int (niltape ?) = midtape sig ls0 x0 rs0 →
405 (∃l,l1.x0::rs0 = l@x::rs@l1 ∧
408 (mk_tape sig (reverse ? rs@[x]) (None ?) [ ]) src)
409 (mk_tape sig ((reverse ? (l@x::rs))@ls0) (option_hd ? l1) (tail ? l1)) dst) ∨
410 ∀l,l1.x0::rs0 ≠ l@x::rs@l1).
412 lemma not_sub_list_merge :
413 ∀T.∀a,b:list T. (∀l1.a ≠ b@l1) → (∀t,l,l1.a ≠ t::l@b@l1) → ∀l,l1.a ≠ l@b@l1.
414 #T #a #b #H1 #H2 #l elim l normalize //
417 lemma not_sub_list_merge_2 :
418 ∀T:DeqSet.∀a,b:list T.∀t. (∀l1.t::a ≠ b@l1) → (∀l,l1.a ≠ l@b@l1) → ∀l,l1.t::a ≠ l@b@l1.
419 #T #a #b #t #H1 #H2 #l elim l //
420 #t0 #l1 #IH #l2 cases (true_or_false (t == t0)) #Htt0
421 [ >(\P Htt0) % normalize #H destruct (H) cases (H2 l1 l2) /2/
422 | normalize % #H destruct (H) cases (\Pf Htt0) /2/ ]
426 lemma wsem_match_m : ∀src,dst,sig,n.
427 src ≠ dst → src < S n → dst < S n →
428 match_m src dst sig n ⊫ R_match_m src dst sig n.
429 #src #dst #sig #n #Hneq #Hsrc #Hdst #ta #k #outc #Hloop
430 lapply (sem_while … (sem_match_step src dst sig n Hneq Hsrc Hdst) … Hloop) //
431 -Hloop * #tb * #Hstar @(star_ind_l ??????? Hstar) -Hstar
432 [ #Hfalse #x #xs #Hmid_src
433 cases (Hfalse … Hmid_src) -Hfalse
434 [(* current dest = None *) *
435 [ * #Hcur_dst #Houtc %
437 | #ls0 #x0 #rs0 #Hmid_dst >Hmid_dst in Hcur_dst;
438 normalize in ⊢ (%→?); #H destruct (H)
440 | * #ls0 * #rs0 * #xs0 * * #Htc_dst #Hrs0 #HNone %
441 [ >Htc_dst normalize in ⊢ (%→?); #H destruct (H)
442 | #ls1 #x1 #rs1 >Htc_dst #H destruct (H)
443 >Hrs0 >HNone cases xs0
444 [ % %{[ ]} %{[ ]} % [ >append_nil >append_nil %]
447 | >reverse_append >reverse_cons >reverse_append
448 >associative_append >associative_append % ]
449 | #x2 #xs2 %2 #l #l1 % #Habs lapply (eq_f ?? (length ?) ?? Habs)
450 >length_append whd in ⊢ (??%(??%)→?); >length_append
451 >length_append normalize >commutative_plus whd in ⊢ (???%→?);
452 #H destruct (H) lapply e0 >(plus_n_O (|rs1|)) in ⊢ (??%?→?);
453 >associative_plus >associative_plus
454 #e1 lapply (injective_plus_r ??? e1) whd in ⊢ (???%→?);
459 |* #ls0 * #rs0 * #Hmid_dst #Houtc %
460 [ >Hmid_dst normalize in ⊢ (%→?); #H destruct (H)
461 |#ls1 #x1 #rs1 >Hmid_dst #H destruct (H)
462 %1 %{[ ]} %{rs0} % [%]
463 >reverse_cons >associative_append >Houtc %
466 |-ta #ta #tc #Htrue #Hstar #IH #Hout lapply (IH Hout) -IH -Hout #IH whd
468 lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
469 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→?);
471 [#Hcurta_dst #Hrightta_dst whd in Htrue; >Hmidta_src in Htrue; #Htrue
472 cases (Htrue ?? (refl ??)) -Htrue #Htc
474 [ >Htc whd in match (tape_move_mono ???); whd in match (tape_write ???);
475 <(change_vec_same … ta dst (niltape ?)) in ⊢ (???%);
476 lapply Hrightta_dst lapply Hcurta_dst -Hrightta_dst -Hcurta_dst
477 cases (nth dst ? ta (niltape ?))
479 | #r0 #rs0 #_ normalize in ⊢ (%→?); #H destruct (H)
481 | #ls #x0 #rs normalize in ⊢ (%→?); #H destruct (H) ] ]
482 -Htc #Htc destruct (Htc) #_
483 cases (IH … Hmidta_src) #Houtc #_ @Houtc //
484 |#ls0 #x0 #rs0 #Hmidta_dst >Hmidta_dst in Hcurta_dst;
485 normalize in ⊢ (%→?); #H destruct (H)
487 | #c #Hcurta_dst % [ >Hcurta_dst #H destruct (H) ]
488 #ls0 #x0 #rs0 #Hmidta_dst >Hmidta_dst in Hcurta_dst; normalize in ⊢ (%→?);
489 #H destruct (H) whd in Htrue; >Hmidta_src in Htrue; #Htrue
490 cases (Htrue ?? (refl …)) -Htrue >Hmidta_dst #Htc
491 cases (true_or_false (x==c)) #eqx
492 [ lapply (\P eqx) -eqx #eqx destruct (eqx) * #s0 * whd in ⊢ (??%?→?); #Hs0
493 destruct (Hs0) #Htrue cases (Htrue (refl ??)) -Htrue
494 #xs0 * #ci * #rs' * #ls1 * #cj * #rs1 * * #Hxs #H destruct (H) #Hcicj
495 >Htc in IH; whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
496 #IH cases (IH … Hmidta_src) -IH #_ >nth_change_vec //
497 cut (∃x1,xs1.xs0@cj::rs1 = x1::xs1)
498 [ cases xs0 [ %{cj} %{rs1} % | #x1 #xs1 %{x1} %{(xs1@cj::rs1)} % ] ] * #x1 * #xs1
499 #Hxs1 >Hxs1 #IH cases (IH … (refl ??)) -IH
500 [ * #l * #l1 * #Hxs1'
501 >change_vec_commute // >change_vec_change_vec
502 #Houtc % %{(s0::l)} %{l1} %
504 | >reverse_cons >associative_append >change_vec_commute // @Houtc ]
505 | #H %2 #l #l1 >(?:l@s0::xs@l1 = l@(s0::xs)@l1) [|%]
507 [ #l2 >Hxs <Hxs1 % normalize #H1 lapply (cons_injective_r ????? H1)
508 >associative_append #H2 lapply (append_l2_injective ????? (refl ??) H2)
509 #H3 lapply (cons_injective_l ????? H3) #H3 >H3 in Hcicj; * /2/
510 |#t #l2 #l3 % normalize #H1 lapply (cons_injective_r ????? H1)
511 -H1 #H1 cases (H l2 l3) #H2 @H2 @H1
514 | #_ cases (IH x xs ?) -IH
515 [| >Htc >nth_change_vec_neq [|@sym_not_eq //] @Hmidta_src ]
516 >Htc >nth_change_vec // cases rs0
517 [ #_ #_ %2 #l #l1 cases l
520 [ normalize % #H destruct (H) cases (\Pf eqx) /2/
521 | #tmp1 #l2 normalize % #H destruct (H) ]
522 | #tmp1 #l2 normalize % #H destruct (H) ]
523 | #tmp1 #l2 normalize % #H destruct (H)cases l2 in e0;
524 [ normalize #H1 destruct (H1)
525 | #tmp2 #l3 normalize #H1 destruct (H1) ] ]
526 | #r1 #rs1 #_ #IH cases (IH … (refl ??)) -IH
527 [ * #l * #l1 * #Hll1 #Houtc % %{(c::l)} %{l1} % [ >Hll1 % ]
528 >Houtc >change_vec_commute // >change_vec_change_vec
529 >change_vec_commute [|@sym_not_eq //]
530 >reverse_cons >associative_append %
531 | #Hll1 %2 @(not_sub_list_merge_2 ?? (x::xs)) normalize [|@Hll1]
532 #l1 % #H destruct (H) cases (\Pf eqx) /2/
540 axiom daemon : ∀P:Prop.P.
542 (* XXX: move to turing (or mono) *)
543 definition option_cons ≝ λsig.λc:option sig.λl.
544 match c with [ None ⇒ l | Some c0 ⇒ c0::l ].
546 definition R_match_step_true_naive ≝
547 λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
548 |left ? (nth src ? outt (niltape ?))| +
549 |option_cons ? (current ? (nth dst ? outt (niltape ?))) (right ? (nth dst ? outt (niltape ?)))| <
550 |left ? (nth src ? int (niltape ?))| +
551 |option_cons ? (current ? (nth dst ? int (niltape ?))) (right ? (nth dst ? int (niltape ?)))|.
553 axiom right_mk_tape : ∀sig,ls,c,rs.right ? (mk_tape sig ls c rs) = rs.
554 axiom left_mk_tape : ∀sig,ls,c,rs.left ? (mk_tape sig ls c rs) = ls.
555 axiom current_mk_tape : ∀sig,ls,c,rs.current ? (mk_tape sig ls c rs) = c.
556 axiom length_tail : ∀A,l.0 < |l| → |tail A l| < |l|.
557 axiom lists_length_split :
558 ∀A.∀l1,l2:list A.(∃la,lb.(|la| = |l1| ∧ l2 = la@lb) ∨ (|la| = |l2| ∧ l1 = la@lb)).
559 axiom opt_cons_tail_expand : ∀A,l.l = option_cons A (option_hd ? l) (tail ? l).
561 lemma sem_match_step_termination :
562 ∀src,dst,sig,n.src ≠ dst → src < S n → dst < S n →
563 match_step src dst sig n ⊨
564 [ inr ?? (inr ?? (inl … (inr ?? start_nop))) :
565 R_match_step_true_naive src dst sig n,
566 R_match_step_false src dst sig n ].
567 #src #dst #sig #n #Hneq #Hsrc #Hdst
568 @(acc_sem_seq_app sig n … (sem_compare src dst sig n Hneq Hsrc Hdst)
569 (acc_sem_if ? n … (sem_partest sig n (match_test src dst sig ?))
571 (sem_rewind_strong ???? Hneq Hsrc Hdst)
572 (sem_inject … dst (le_S_S_to_le … Hdst) (sem_move_r ? )))
574 [ #ta #tb #tc * lapply (refl ? (current ? (nth src ? ta (niltape ?))))
575 cases (current ? (nth src ? ta (niltape ?))) in ⊢ (???%→%);
576 [ #Hcurta_src #Hcomp #_ * #td * >Hcomp [| % %2 %]
577 whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
578 >nth_current_chars >Hcurta_src normalize in ⊢ (%→?); #H destruct (H)
579 | #s #Hs lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
580 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→%);
581 [ #Hcurta_dst #Hcomp #_ * #td * >Hcomp [| %2 %]
582 whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
583 >nth_current_chars >nth_current_chars >Hs >Hcurta_dst
584 normalize in ⊢ (%→?); #H destruct (H)
586 cases (current_to_midtape … Hs) #ls * #rs #Hmidta_src >Hmidta_src
587 cases (current_to_midtape … Hs0) #ls0 * #rs0 #Hmidta_dst >Hmidta_dst
588 cases (true_or_false (s == s0)) #Hss0
589 [ lapply (\P Hss0) -Hss0 #Hss0 destruct (Hss0)
590 #_ #Hcomp cases (Hcomp ????? (refl ??) (refl ??)) -Hcomp [ *
591 [ * #rs' * #_ #Hcurtc_dst * #td * whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
592 >nth_current_chars >nth_current_chars >Hcurtc_dst
593 cases (current ? (nth src …))
594 [normalize in ⊢ (%→?); #H destruct (H)
595 | #x >nth_change_vec // cases (reverse ? rs0)
596 [ normalize in ⊢ (%→?); #H destruct (H)
597 | #r1 #rs1 normalize in ⊢ (%→?); #H destruct (H) ] ]
598 | * #rs0' * #_ #Hcurtc_src * #td * whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
599 >(?:nth src ? (current_chars ?? tc) (None ?) = None ?)
600 [|>nth_current_chars >Hcurtc_src >nth_change_vec_neq
601 [>nth_change_vec [cases (append ???) // | @Hsrc]
602 |@(not_to_not … Hneq) //
604 normalize in ⊢ (%→?); #H destruct (H) ]
605 | * #xs * #ci * #cj * #rs'' * #rs0' * * * #Hcicj #Hrs #Hrs0
606 #Htc * #td * * #Hmatch #Htd destruct (Htd) * #te * * *
607 >Htc >change_vec_commute // >nth_change_vec //
608 >change_vec_commute [|@sym_not_eq //] >nth_change_vec //
609 cases (lists_length_split ? ls ls0) #lsa * #lsb * * #Hlen #Hlsalsb
611 [ #Hte #_ #_ <(reverse_reverse … ls) in Hte; <(reverse_reverse … lsa)
612 cut (|reverse ? lsa| = |reverse ? ls|) [ // ] #Hlen'
613 @(list_cases2 … Hlen')
614 [ #H1 #H2 >H1 >H2 -H1 -H2 normalize in match (reverse ? [ ]); #Hte #_
615 lapply (Hte … (refl ??) … (refl ??) (refl ??)) -Hte
616 >change_vec_commute // >change_vec_change_vec
617 >change_vec_commute [|@sym_not_eq //] >change_vec_change_vec #Hte
618 >Hte * * #_ >nth_change_vec // >reverse_reverse
619 #H lapply (H … (refl ??)) -H #Htb1 #Htb2
620 cut (tb = change_vec ?? (change_vec (tape sig) (S n) ta (midtape sig [] s0 (xs@ci::rs'')) src) (mk_tape sig (s0::lsb) (option_hd sig (xs@cj::rs0')) (tail sig (xs@cj::rs0'))) dst)
621 [@daemon] -Htb1 -Htb2 #Htb >Htb whd >nth_change_vec //
622 >nth_change_vec_neq [|@sym_not_eq //] >nth_change_vec //
623 >right_mk_tape normalize in match (left ??);
624 >Hmidta_src >Hmidta_dst >current_mk_tape <opt_cons_tail_expand
625 whd in match (option_cons ???); >Hrs0
626 normalize in ⊢ (?(?%)%); //
627 | #hda #hdb #tla #tlb #H1 #H2 >H1 >H2
628 >reverse_cons >reverse_cons #Hte
629 lapply (Hte ci hdb (reverse ? xs@s0::reverse ? tlb) rs'' ?
630 lsb cj hda (reverse ? xs@s0::reverse ? tla) rs0' ??)
631 [ /2 by cons_injective_l, nil/
632 | >length_append >length_append @eq_f @(eq_f ?? S)
633 >H1 in Hlen'; >H2 whd in ⊢ (??%%→?); #Hlen'
634 >length_reverse >length_reverse destruct (Hlen') //
635 | /2 by refl, trans_eq/ ] -Hte
636 #Hte #_ * * #_ >Hte >nth_change_vec // #Htb1 #Htb2
637 cut (tb = change_vec ?? (change_vec (tape sig) (S n) ta
638 (mk_tape sig (hda::lsb) (option_hd ? (reverse sig (reverse sig xs@s0::reverse sig tla)@cj::rs0')) (tail ? (reverse sig (reverse sig xs@s0::reverse sig tla)@cj::rs0'))) dst)
639 (midtape ? [ ] hdb (reverse sig (reverse sig xs@s0::reverse sig tlb)@ci::rs'')) src)
640 [@daemon] -Htb1 -Htb2 #Htb >Htb whd
641 >nth_change_vec // >nth_change_vec_neq // >nth_change_vec //
642 >right_mk_tape >Hmidta_src >Hmidta_dst
643 whd in match (left ??); whd in match (left ??); whd in match (right ??);
644 >current_mk_tape <opt_cons_tail_expand whd in match (option_cons ???);
645 >Hrs0 >length_append whd in ⊢ (??(??%)); >length_append >length_reverse
646 >length_append >commutative_plus in match (|reverse ??| + ?);
647 whd in match (|?::?|); >length_reverse >length_reverse
648 <(length_reverse ? ls) <Hlen' >H1 normalize // ]
649 | #_ #Hte #_ <(reverse_reverse … ls0) in Hte; <(reverse_reverse … lsa)
650 cut (|reverse ? lsa| = |reverse ? ls0|) [ // ] #Hlen'
651 @(list_cases2 … Hlen')
652 [ #H1 #H2 >H1 >H2 normalize in match (reverse ? [ ]); #Hte
653 lapply (Hte … (refl ??) … (refl ??) (refl ??)) -Hte
654 >change_vec_change_vec >change_vec_commute [|@sym_not_eq //]
655 >change_vec_change_vec #Hte #_
656 >Hte * * #_ >nth_change_vec // >reverse_reverse
657 #H lapply (H … (refl ??)) -H #Htb1 #Htb2
658 cut (tb = change_vec ?? (change_vec (tape sig) (S n) ta (mk_tape ? [s0] (option_hd ? (xs@cj::rs0')) (tail ? (xs@cj::rs0'))) dst)
659 (midtape ? lsb s0 (xs@ci::rs'')) src)
660 [@daemon] -Htb1 -Htb2 #Htb >Htb whd >nth_change_vec //
661 >nth_change_vec_neq // >nth_change_vec //
662 >right_mk_tape normalize in match (left ??);
663 >Hmidta_src >Hmidta_dst >current_mk_tape <opt_cons_tail_expand >Hrs0
664 >length_append normalize >length_append >length_append
665 <(reverse_reverse ? lsa) >H1 normalize //
666 | #hda #hdb #tla #tlb #H1 #H2 >H1 >H2
667 >reverse_cons >reverse_cons #Hte
668 lapply (Hte cj hdb (reverse ? xs@s0::reverse ? tlb) rs0' ?
669 lsb ci hda (reverse ? xs@s0::reverse ? tla) rs'' ??)
670 [ /2 by cons_injective_l, nil/
671 | >length_append >length_append @eq_f @(eq_f ?? S)
672 >H1 in Hlen'; >H2 whd in ⊢ (??%%→?); #Hlen'
673 >length_reverse >length_reverse destruct (Hlen') //
674 | /2 by refl, trans_eq/ ] -Hte
675 #Hte #_ * * #_ >Hte >nth_change_vec_neq // >nth_change_vec // #Htb1 #Htb2
676 cut (tb = change_vec ?? (change_vec (tape sig) (S n) ta
677 (mk_tape sig [hdb] (option_hd ? (reverse sig (reverse sig xs@s0::reverse sig tlb)@cj::rs0')) (tail ? (reverse sig (reverse sig xs@s0::reverse sig tlb)@cj::rs0'))) dst)
678 (midtape ? lsb hda (reverse sig (reverse sig xs@s0::reverse sig tla)@ci::rs'')) src)
679 [@daemon] -Htb1 -Htb2 #Htb >Htb whd
680 >nth_change_vec // >nth_change_vec_neq // >nth_change_vec //
681 >right_mk_tape >Hmidta_src >Hmidta_dst
682 whd in match (left ??); whd in match (left ??); whd in match (right ??);
683 >current_mk_tape <opt_cons_tail_expand
684 whd in match (option_cons ???);
685 >Hrs0 >length_append whd in ⊢ (??(??%)); >length_append >length_reverse
686 >length_append >commutative_plus in match (|reverse ??| + ?);
687 whd in match (|?::?|); >length_reverse >length_reverse
688 <(length_reverse ? lsa) >Hlen' >H2 >length_append
693 | lapply (\Pf Hss0) -Hss0 #Hss0 #Htc cut (tc = ta)
694 [@Htc % % @(not_to_not ??? Hss0) #H destruct (H) %]
695 -Htc #Htc destruct (Htc) #_ * #td * whd in ⊢ (%→?); * #_
696 #Htd destruct (Htd) * #te * * * * >Hmidta_src >Hmidta_dst
697 cases (lists_length_split ? ls ls0) #lsa * #lsb * * #Hlen #Hlsalsb
699 [ <(reverse_reverse … ls) <(reverse_reverse … lsa)
700 cut (|reverse ? lsa| = |reverse ? ls|) [ // ] #Hlen'
701 @(list_cases2 … Hlen')
702 [ #H1 #H2 >H1 >H2 -H1 -H2 #_ #_ normalize in match (reverse ? [ ]); #Hte #_
703 lapply (Hte … (refl ??) … (refl ??)) -Hte #Hte destruct (Hte) * * #_
704 >Hmidta_dst #Htb1 lapply (Htb1 … (refl ??)) -Htb1 #Htb1 #Htb2
705 cut (tb = change_vec ?? ta (mk_tape ? (s0::lsa@lsb) (option_hd ? rs0) (tail ? rs0)) dst)
706 [@daemon] -Htb1 -Htb2 #Htb >Htb whd >nth_change_vec //
707 >nth_change_vec_neq [|@sym_not_eq //] >Hmidta_src >Hmidta_dst
708 >right_mk_tape normalize in match (left ??); normalize in match (right ??);
709 >Hmidta_src >Hmidta_dst >current_mk_tape <opt_cons_tail_expand
711 | #hda #hdb #tla #tlb #H1 #H2 >H1 >H2
712 >reverse_cons >reverse_cons >associative_append #Hte
713 lapply (Hte ???? (refl ??) ? s0 ? (reverse ? tla) ?? (refl ??))
714 [ >length_reverse >length_reverse cut (|hda::tla| = |hdb::tlb|) //
715 normalize #H destruct (H) // ] #Hte #_ #_ #_
716 * * #_ >Hte >nth_change_vec // #Htb1 #Htb2
717 cut (tb = change_vec ?? (change_vec (tape sig) (S n) ta
718 (mk_tape sig (hda::lsb) (option_hd ? (reverse sig (reverse sig tla)@s0::rs0)) (tail ? (reverse sig (reverse sig tla)@s0::rs0))) dst)
719 (midtape ? [ ] hdb (reverse sig (reverse sig tlb)@s::rs)) src)
720 [@daemon] -Htb1 -Htb2 #Htb >Htb whd
721 >nth_change_vec // >nth_change_vec_neq // >nth_change_vec //
722 >right_mk_tape >Hmidta_src >Hmidta_dst
723 whd in match (left ??); whd in match (left ??); whd in match (right ??);
724 >current_mk_tape <opt_cons_tail_expand >length_append
725 >length_reverse >length_reverse <(length_reverse ? ls) <Hlen'
727 | #_ <(reverse_reverse … ls0) <(reverse_reverse … lsa)
728 cut (|reverse ? lsa| = |reverse ? ls0|) [ // ] #Hlen'
729 @(list_cases2 … Hlen')
730 [ #H1 #H2 >H1 >H2 normalize in match (reverse ? [ ]); #_ #_ #Hte
731 lapply (Hte … (refl ??) … (refl ??)) -Hte #Hte destruct (Hte)
732 * * #_ >Hmidta_dst #Htb1 lapply (Htb1 … (refl ??)) -Htb1 #Htb1 #Htb2
733 cut (tb = change_vec (tape sig) (S n) ta (mk_tape ? (s0::ls0) (option_hd ? rs0) (tail ? rs0)) dst)
734 [@daemon] -Htb1 -Htb2 #Htb >Htb whd >nth_change_vec //
735 >nth_change_vec_neq [|@sym_not_eq //] >Hmidta_src >Hmidta_dst
736 >current_mk_tape >right_mk_tape normalize in ⊢ (??%); <opt_cons_tail_expand
738 | #hda #hdb #tla #tlb #H1 #H2 >H1 >H2
739 >reverse_cons >reverse_cons #Hte #_ #_
740 lapply (Hte s0 hdb (reverse ? tlb) rs0 ?
741 lsb s hda (reverse ? tla) rs ??)
742 [ /2 by cons_injective_l, nil/
743 | >length_reverse >length_reverse cut (|hda::tla| = |hdb::tlb|) //
744 normalize #H destruct (H) //
745 | /2 by refl, trans_eq/ ] -Hte
746 #Hte * * #_ >Hte >nth_change_vec_neq // >nth_change_vec // #Htb1 #Htb2
747 cut (tb = change_vec ?? (change_vec (tape sig) (S n) ta
748 (mk_tape sig [hdb] (option_hd ? (reverse sig (reverse sig tlb)@s0::rs0)) (tail ? (reverse sig (reverse sig tlb)@s0::rs0))) dst)
749 (midtape ? lsb hda (reverse sig (reverse sig tla)@s::rs)) src)
750 [@daemon] -Htb1 -Htb2 #Htb >Htb whd
751 >nth_change_vec // >nth_change_vec_neq // >nth_change_vec //
752 >right_mk_tape >Hmidta_src >Hmidta_dst
753 whd in match (left ??); whd in match (left ??); whd in match (right ??);
754 >current_mk_tape <opt_cons_tail_expand >length_append
755 normalize in ⊢ (??%); >length_append >reverse_reverse
756 <(length_reverse ? lsa) >Hlen' >H2 normalize //
762 | #ta #tb #tc * #Hcomp1 #Hcomp2 * #td * * #Htest #Htd destruct (Htd)
763 whd in ⊢ (%→?); #Htb destruct (Htb) #ls #x #xs #Hta_src
764 lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
765 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→?);
766 [ #Hcurta_dst % % % // @Hcomp1 %2 //
767 | #x0 #Hcurta_dst cases (current_to_midtape … Hcurta_dst) -Hcurta_dst
768 #ls0 * #rs0 #Hta_dst cases (true_or_false (x == x0)) #Hxx0
769 [ lapply (\P Hxx0) -Hxx0 #Hxx0 destruct (Hxx0)
770 | >(?:tc=ta) in Htest;
771 [|@Hcomp1 % % >Hta_src >Hta_dst @(not_to_not ??? (\Pf Hxx0)) normalize
772 #Hxx0' destruct (Hxx0') % ]
774 >nth_current_chars >Hta_src >nth_current_chars >Hta_dst
775 whd in ⊢ (??%?→?); #Hfalse destruct (Hfalse) ] -Hcomp1
776 cases (Hcomp2 … Hta_src Hta_dst) [ *
777 [ * #rs' * #Hxs #Hcurtc % %2 %{ls0} %{rs0} %{rs'} %
779 | * #rs0' * #Hxs #Htc %2 >Htc %{ls0} %{rs0'} % // ]
780 | * #xs0 * #ci * #cj * #rs' * #rs0' * * *
781 #Hci #Hxs #Hrs0 #Htc @False_ind
783 >(?:nth src ? (current_chars ?? tc) (None ?) = Some ? ci) in Htest;
784 [|>nth_current_chars >Htc >nth_change_vec_neq [|@(not_to_not … Hneq) //]
786 >(?:nth dst ? (current_chars ?? tc) (None ?) = Some ? cj)
787 [|>nth_current_chars >Htc >nth_change_vec //]
788 normalize #H destruct (H) ] ] ]
792 definition Pre_match_m ≝
793 λsrc,sig,n.λt: Vector (tape sig) (S n).
795 nth src (tape sig) t (niltape sig) = midtape ? [] x xs.
797 lemma terminate_match_m :
799 src ≠ dst → src < S n → dst < S n →
800 Pre_match_m src sig n t →
801 match_m src dst sig n ↓ t.
802 #src #dst #sig #n #t #Hneq #Hsrc #Hdst * #start * #xs
804 @(terminate_while … (sem_match_step src dst sig n Hneq Hsrc Hdst)) //
805 <(change_vec_same … t dst (niltape ?))
806 lapply (refl ? (nth dst (tape sig) t (niltape ?)))
807 cases (nth dst (tape sig) t (niltape ?)) in ⊢ (???%→?);
808 [ #Htape_dst % #t1 whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
809 >Hmid_src #HR cases (HR ?? (refl ??)) -HR
810 >nth_change_vec // >Htape_dst #_ * #s0 * normalize in ⊢ (%→?); #H destruct (H)
811 | #x0 #xs0 #Htape_dst % #t1 whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
812 >Hmid_src #HR cases (HR ?? (refl ??)) -HR
813 >nth_change_vec // >Htape_dst #_ normalize in ⊢ (%→?);
814 * #s0 * #H destruct (H)
815 | #x0 #xs0 #Htape_dst % #t1 whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
816 >Hmid_src #HR cases (HR ?? (refl ??)) -HR
817 >nth_change_vec // >Htape_dst #_ normalize in ⊢ (%→?);
818 * #s0 * #H destruct (H)
819 | #ls #s #rs lapply s -s lapply ls -ls lapply Hmid_src lapply t -t elim rs
820 [#t #Hmid_src #ls #s #Hmid_dst % #t1 whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
821 >Hmid_src >nth_change_vec // >Hmid_dst #HR cases (HR ?? (refl ??)) -HR
822 >change_vec_change_vec #Ht1 #_ % #t2 whd in ⊢ (%→?);
823 >Ht1 >nth_change_vec_neq [|@sym_not_eq //] >Hmid_src #HR
824 cases (HR ?? (refl ??)) -HR #_
825 >nth_change_vec // * #s1 * normalize in ⊢ (%→?); #H destruct (H)
826 |#r0 #rs0 #IH #t #Hmid_src #ls #s #Hmid_dst % #t1 whd in ⊢ (%→?);
827 >nth_change_vec_neq [|@sym_not_eq //] >Hmid_src
828 #Htrue cases (Htrue ?? (refl ??)) -Htrue >change_vec_change_vec
829 >nth_change_vec // >Hmid_dst whd in match (tape_move_mono ???); #Ht1
830 * #s0 * whd in ⊢ (??%?→?); #H destruct (H) #_ >Ht1
831 lapply (IH t1 ? (s0::ls) r0 ?)
832 [ >Ht1 >nth_change_vec //
833 | >Ht1 >nth_change_vec_neq [|@sym_not_eq //] @Hmid_src
834 | >Ht1 >nth_change_vec // ]