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 ≝ 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 theorem accRealize_to_Realize :
125 ∀sig,n.∀M:mTM sig n.∀Rtrue,Rfalse,acc.
126 M ⊨ [ acc: Rtrue, Rfalse ] → M ⊨ Rtrue ∪ Rfalse.
127 #sig #n #M #Rtrue #Rfalse #acc #HR #t
128 cases (HR t) #k * #outc * * #Hloop
129 #Htrue #Hfalse %{k} %{outc} % //
130 cases (true_or_false (cstate sig (states sig n M) n outc == acc)) #Hcase
131 [ % @Htrue @(\P Hcase) | %2 @Hfalse @(\Pf Hcase) ]
134 lemma sem_rewind : ∀src,dst,sig,n.
135 src ≠ dst → src < S n → dst < S n →
136 rewind src dst sig n ⊨ R_rewind src dst sig n.
137 #src #dst #sig #n #Hneq #Hsrc #Hdst
138 @(sem_seq_app sig n ????? (sem_parmoveL src dst sig n Hneq Hsrc Hdst) ?)
139 [| @(sem_seq_app sig n ????? (sem_move_r_multi …) (sem_move_r_multi …)) //
141 #ta #tb * #tc * * #Htc #_ * #td * whd in ⊢ (%→%→?); #Htd #Htb
142 #x #x0 #xs #rs #Hmidta_src #ls0 #y #y0 #target #rs0 #Hlen #Hmidta_dst
143 >(Htc ??? Hmidta_src ls0 y (target@[y0]) rs0 ??) in Htd;
145 |>length_append >length_append >Hlen % ] * #_
146 [ whd in ⊢ (%→?); * #x1 * #x2 * *
147 >change_vec_commute in ⊢ (%→?); // >nth_change_vec //
148 cases (reverse sig (xs@[x0])@x::rs)
149 [|#z #zs] normalize in ⊢ (%→?); #H destruct (H)
150 | whd in ⊢ (%→?); * #_ #Htb >Htb -Htb FAIL
152 normalize in ⊢ (%→?);
153 (sem_parmove_step src dst sig n R Hneq Hsrc Hdst))
154 (acc_sem_if ? n … (sem_partest sig n (match_test src dst sig ?))
156 (sem_parmoveL ???? Hneq Hsrc Hdst)
157 (sem_inject … dst (le_S_S_to_le … Hdst) (sem_move_r ? )))
161 definition match_step ≝ λsrc,dst,sig,n.
162 compare src dst sig n ·
163 (ifTM ?? (partest sig n (match_test src dst sig ?))
165 (rewind src dst sig n · (inject_TM ? (move_r ?) n dst)))
169 definition R_match_step_false ≝
170 λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
172 nth src ? int (niltape ?) = midtape sig ls x xs →
173 ((current sig (nth dst (tape sig) int (niltape sig)) = None ?) ∧ outt = int) ∨
174 (∃ls0,rs0,xs0. nth dst ? int (niltape ?) = midtape sig ls0 x rs0 ∧
176 current sig (nth dst (tape sig) outt (niltape sig)) = None ?) ∨
178 nth dst ? int (niltape ?) = midtape sig ls0 x (xs@rs0) ∧
182 (change_vec ?? int (mk_tape sig (reverse ? xs@x::ls) (None ?) [ ]) src)
183 (mk_tape sig (reverse ? xs@x::ls0) (option_hd ? rs0) (tail ? rs0)) dst).
185 (*definition R_match_step_true ≝
186 λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
187 ∀s,rs.current sig (nth src (tape sig) int (niltape sig)) = Some ? s →
188 current sig (nth dst (tape sig) int (niltape sig)) ≠ None ? ∧
189 (∀s1.current sig (nth dst (tape sig) int (niltape sig)) = Some ? s1 → s ≠ s1 →
190 outt = change_vec ?? int
191 (tape_move_mono … (nth dst ? int (niltape ?)) (〈Some ? s1,R〉)) dst) ∧
192 (∀ls,x,xs,ci,rs,ls0,rs0.
193 nth src ? int (niltape ?) = midtape sig ls x (xs@ci::rs) →
194 nth dst ? int (niltape ?) = midtape sig ls0 x (xs@rs0) →
196 ∀cj,rs1.rs0 = cj::rs1 →
198 (outt = change_vec ?? int
199 (tape_move_mono … (nth dst ? int (niltape ?)) (〈None ?,R〉)) dst)).
201 definition R_match_step_true ≝
202 λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
203 ∀s.current sig (nth src (tape sig) int (niltape sig)) = Some ? s →
204 ∃s1.current sig (nth dst (tape sig) int (niltape sig)) = Some ? s1 ∧
205 (left ? (nth src ? int (niltape ?)) = [ ] →
207 outt = change_vec ?? int
208 (tape_move_mono … (nth dst ? int (niltape ?)) (〈None ?,R〉)) dst) ∧
210 nth src ? int (niltape ?) = midtape sig [] s (xs@ci::rs) →
211 nth dst ? int (niltape ?) = midtape sig ls0 s (xs@rs0) →
213 ∀cj,rs1.rs0 = cj::rs1 →
215 (outt = change_vec ?? int
216 (tape_move_mono … (nth dst ? int (niltape ?)) (〈None ?,R〉)) dst))).
218 lemma sem_match_step :
219 ∀src,dst,sig,n.src ≠ dst → src < S n → dst < S n →
220 match_step src dst sig n ⊨
221 [ inr ?? (inr ?? (inl … (inr ?? start_nop))) :
222 R_match_step_true src dst sig n,
223 R_match_step_false src dst sig n ].
224 #src #dst #sig #n #Hneq #Hsrc #Hdst
225 @(acc_sem_seq_app sig n … (sem_compare src dst sig n Hneq Hsrc Hdst)
226 (acc_sem_if ? n … (sem_partest sig n (match_test src dst sig ?))
228 (sem_parmoveL ???? Hneq Hsrc Hdst)
229 (sem_inject … dst (le_S_S_to_le … Hdst) (sem_move_r ? )))
231 [#ta #tb #tc * #Hcomp1 #Hcomp2 * #td * #Htest
232 * #te * #Hte #Htb #s #Hcurta_src whd
233 cut (∃s1.current sig (nth dst (tape sig) ta (niltape sig))=Some sig s1)
234 [ lapply Hcomp1 -Hcomp1
235 lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
236 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→%);
237 [ #Hcurta_dst #Hcomp1 >Hcomp1 in Htest; // *
238 change with (vec_map ?????) in match (current_chars ???); whd in ⊢ (??%?→?);
239 <(nth_vec_map ?? (current ?) src ? ta (niltape ?))
240 <(nth_vec_map ?? (current ?) dst ? ta (niltape ?))
241 >Hcurta_src >Hcurta_dst whd in ⊢ (??%?→?); #H destruct (H)
242 | #s1 #_ #_ %{s1} % ] ]
243 * #s1 #Hcurta_dst %{s1} % // #Hleftta %
244 [ #Hneqss1 -Hcomp2 cut (tc = ta)
245 [@Hcomp1 %1 %1 >Hcurta_src >Hcurta_dst @(not_to_not … Hneqss1) #H destruct (H) //]
246 #H destruct (H) -Hcomp1 cut (td = ta)
247 [ cases Htest -Htest // ] #Htdta destruct (Htdta)
248 cases Hte -Hte #Hte #_
249 cases (current_to_midtape … Hcurta_src) #ls * #rs #Hmidta_src
250 cases (current_to_midtape … Hcurta_dst) #ls0 * #rs0 #Hmidta_dst
251 >Hmidta_src in Hleftta; normalize in ⊢ (%→?); #Hls destruct (Hls)
252 >(Hte s [ ] rs Hmidta_src ls0 s1 [ ] rs0 (refl ??) Hmidta_dst) in Htb;
258 [ cases Htest -Htest #Htest #Htdta <Htdta @Hte %1 >Htdta @Hcurta_src %{s} % //]
259 -Hte #H destruct (H) %
260 [cases Htb * #_ #Hmove #Hmove1 @(eq_vec … (niltape … ))
261 #i #Hi cases (decidable_eq_nat i dst) #Hidst
262 [ >Hidst >nth_change_vec // cases (current_to_midtape … Hcurta_dst)
263 #ls * #rs #Hta_mid >(Hmove … Hta_mid) >Hta_mid cases rs //
264 | >nth_change_vec_neq [|@sym_not_eq //] @sym_eq @Hmove1 @sym_not_eq // ]
265 | whd in Htest:(??%?); >(nth_vec_map ?? (current sig)) in Hcurta_src; #Hcurta_src
266 >Hcurta_src in Htest; whd in ⊢ (??%?→?);
267 cases (is_endc s) // whd in ⊢ (??%?→?); #H @sym_eq //
269 <(nth_vec_map ?? (current ?) dst ? tc (niltape ?))
270 >Hcurta_src normalize
271 lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
272 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→%);
274 [ % #Hfalse destruct (Hfalse)
275 | #s1' #Hs1 destruct (Hs1) #Hneqss1 -Hcomp2
277 [@Hcomp1 %1 %1 >Hcurta_src >Hcurta_dst @(not_to_not … Hneqss1) #H destruct (H) //]
278 #H destruct (H) -Hcomp1 cases Hte -Hte #_ #Hte
279 cut (te = ta) [ cases Htest -Htest #Htest #Htdta <Htdta @Hte %1 %{s} % //] -Hte #H destruct (H) %
280 [cases Htb * #_ #Hmove #Hmove1 @(eq_vec … (niltape … ))
281 #i #Hi cases (decidable_eq_nat i dst) #Hidst
282 [ >Hidst >nth_change_vec // cases (current_to_midtape … Hcurta_dst)
283 #ls * #rs #Hta_mid >(Hmove … Hta_mid) >Hta_mid cases rs //
284 | >nth_change_vec_neq [|@sym_not_eq //] @sym_eq @Hmove1 @sym_not_eq // ]
285 | whd in Htest:(??%?); >(nth_vec_map ?? (current sig)) in Hcurta_src; #Hcurta_src
286 >Hcurta_src in Htest; whd in ⊢ (??%?→?);
287 cases (is_endc s) // whd in ⊢ (??%?→?); #H @sym_eq //
291 #Hcurta_dst >Hcomp1 in Htest; [| %2 %2 //]
292 whd in ⊢ (??%?→?); change with (current ? (niltape ?)) in match (None ?);
293 <nth_vec_map >Hcurta_src whd in ⊢ (??%?→?); <nth_vec_map
294 >Hcurta_dst cases (is_endc s) normalize in ⊢ (%→?); #H destruct (H)
295 | #Hstart #Hnotstart %
296 [ #s1 #Hcurta_dst #Hneqss1 -Hcomp2
298 [@Hcomp1 %2 %1 %1 >Hcurta_src >Hcurta_dst @(not_to_not … Hneqss1) #H destruct (H) //]
299 #H destruct (H) -Hcomp1 cases Hte #_ -Hte #Hte
300 cut (te = ta) [@Hte %1 %1 %{s} % //] -Hte #H destruct (H) %
301 [cases Htb * #_ #Hmove #Hmove1 @(eq_vec … (niltape … ))
302 #i #Hi cases (decidable_eq_nat i dst) #Hidst
303 [ >Hidst >nth_change_vec // cases (current_to_midtape … Hcurta_dst)
304 #ls * #rs #Hta_mid >(Hmove … Hta_mid) >Hta_mid cases rs //
305 | >nth_change_vec_neq [|@sym_not_eq //] @sym_eq @Hmove1 @sym_not_eq // ]
306 | whd in Htest:(??%?); >(nth_vec_map ?? (current sig)) in Hcurta_src; #Hcurta_src
307 >Hcurta_src in Htest; whd in ⊢ (??%?→?);
308 cases (is_endc s) // whd in ⊢ (??%?→?); #H @sym_eq //
310 |#ls #x #xs #ci #rs #ls0 #rs00 #Htasrc_mid #Htadst_mid #Hnotendc
311 cases (Hcomp2 … Htasrc_mid Htadst_mid Hnotendc)
312 [ * #Hrs00 #Htc >Htc in Htest; whd in ⊢ (??%?→?);
313 <(nth_vec_map ?? (current sig) ??? (niltape ?))
314 >change_vec_commute // >nth_change_vec // whd in ⊢ (??%?→?);
316 [ whd in ⊢ (??%?→?); #H destruct (H)
317 | <(nth_vec_map ?? (current sig) ??? (niltape ?))
318 >change_vec_commute [| @sym_not_eq // ] >nth_change_vec //
319 >(?:current ? (mk_tape ?? (None ?) ?) = None ?)
320 [ whd in ⊢ (??%?→?); #H destruct (H)
321 | cases (reverse sig xs@x::ls0) normalize // ] ] ]
322 * #cj' * #rs0' * #Hcjrs0 destruct (Hcjrs0) -Hcomp2 #Hcomp2 % [ %
323 [ cases (true_or_false (is_endc ci)) //
324 #Hendci >(Hcomp2 (or_introl … Hendci)) in Htest;
325 whd in ⊢ (??%?→?); <(nth_vec_map ?? (current sig) ??? (niltape ?))
326 >change_vec_commute // >nth_change_vec // whd in ⊢ (??%?→?);
328 | % #H destruct (H) ] ] #cj #rs1 #H destruct (H) #Hcicj
329 lapply (Hcomp2 (or_intror ?? Hcicj)) -Hcomp2 #Htc %
330 [ cases Hte -Hte #Hte #_ whd in Hte;
331 >Htasrc_mid in Hcurta_src; whd in ⊢ (??%?→?); #H destruct (H)
332 lapply (Hte ls ci (reverse ? xs) rs s ??? ls0 cj (reverse ? xs) s rs1 (refl ??) ?) //
333 [ >Htc >nth_change_vec //
334 | #c0 #Hc0 @(Hnotstart c0) >Htasrc_mid cases (orb_true_l … Hc0) -Hc0 #Hc0
335 [@memb_append_l2 >(\P Hc0) @memb_hd
336 |@memb_append_l1 <(reverse_reverse …xs) @memb_reverse //
338 | >Htc >change_vec_commute // >nth_change_vec // ] -Hte
339 >Htc >change_vec_commute // >change_vec_change_vec
340 >change_vec_commute [|@sym_not_eq //] >change_vec_change_vec #Hte
341 >Hte in Htb; * * #_ >reverse_reverse #Htbdst1 #Htbdst2 -Hte @(eq_vec … (niltape ?))
342 #i #Hi cases (decidable_eq_nat i dst) #Hidst
343 [ >Hidst >nth_change_vec // >(Htbdst1 ls0 s (xs@cj::rs1))
344 [| >nth_change_vec // ]
345 >Htadst_mid cases xs //
346 | >nth_change_vec_neq [|@sym_not_eq // ]
347 <Htbdst2 [| @sym_not_eq // ] >nth_change_vec_neq [| @sym_not_eq // ]
348 <Htasrc_mid >change_vec_same % ]
349 | >Hcurta_src in Htest; whd in ⊢(??%?→?);
350 >Htc >change_vec_commute //
351 change with (current ? (niltape ?)) in match (None ?);
352 <nth_vec_map >nth_change_vec // whd in ⊢ (??%?→?);
353 cases (is_endc ci) whd in ⊢ (??%?→?); #H destruct (H) %
357 |#intape #outtape #ta * #Hcomp1 #Hcomp2 * #tb * * #Hc #Htb
358 whd in ⊢ (%→?); #Hout >Hout >Htb whd
359 #ls #c_src #xs #end #rs #Hmid_src #Hnotend #Hend
360 lapply (current_to_midtape sig (nth dst ? intape (niltape ?)))
361 cases (current … (nth dst ? intape (niltape ?))) in Hcomp1;
362 [#Hcomp1 #_ %1 % % [% | @Hcomp1 %2 %2 % ]
363 |#c_dst cases (true_or_false (c_src == c_dst)) #Hceq
364 [#_ #Hmid_dst cases (Hmid_dst c_dst (refl …)) -Hmid_dst
365 #ls_dst * #rs_dst #Hmid_dst
366 cases (comp_list … (xs@end::rs) rs_dst is_endc) #xs1 * #rsi * #rsj * * *
367 #Hrs_src #Hrs_dst #Hnotendxs1 #Hneq >Hrs_dst in Hmid_dst; #Hmid_dst
368 cut (∃r1,rs1.rsi = r1::rs1)
369 [cases rsi in Hrs_src;
370 [ >append_nil #H <H in Hnotendxs1; #Hnotendxs1
371 >(Hnotendxs1 end) in Hend; [ #H1 destruct (H1) ]
372 @memb_append_l2 @memb_hd
373 | #r1 #rs1 #_ %{r1} %{rs1} % ] ]
374 * #r1 * #rs1 #Hrs1 >Hrs1 in Hrs_src;
375 #Hrs_src >Hrs_src in Hmid_src; #Hmid_src <(\P Hceq) in Hmid_dst; #Hmid_dst
376 lapply (Hcomp2 ??????? Hmid_src Hmid_dst ?)
377 [ #c0 #Hc0 cases (orb_true_l … Hc0) -Hc0 #Hc0
378 [ >(\P Hc0) @Hnotend @memb_hd | @Hnotendxs1 //] ]
380 [ * #Hrsj >Hrsj #Hta % %2 >Hta >nth_change_vec //
381 %{ls_dst} %{xs1} cut (∃xs0.xs = xs1@xs0)
382 [lapply Hnotendxs1 -Hnotendxs1 lapply Hrs_src lapply xs elim xs1
385 [ whd in ⊢ (??%%→?); #H destruct (H) #Hnotendxs2
386 >Hnotendxs2 in Hend; [ #H destruct (H) |@memb_hd ]
387 | #x2' #xs2' whd in ⊢ (??%%→?); #H destruct (H)
388 #Hnotendxs2 cases (IH xs2' e0 ?)
389 [ #xs0 #Hxs2 %{xs0} @eq_f //
390 |#c #Hc @Hnotendxs2 @memb_cons // ]
393 ] * #xs0 #Hxs0 %{xs0} % [ %
394 [ >Hmid_dst >Hrsj >append_nil %
396 | cases (reverse ? xs1) // ]
397 | * #cj * #rs2 * #Hrsj #Hta lapply (Hta ?)
398 [ cases (Hneq ?? Hrs1) /2/ * #_ #Hr1 %2 @(Hr1 ?? Hrsj) ] -Hta #Hta
399 %2 >Hta in Hc; whd in ⊢ (??%?→?);
400 change with (current ? (niltape ?)) in match (None ?);
401 <nth_vec_map >nth_change_vec_neq [|@sym_not_eq //] >nth_change_vec //
402 whd in ⊢ (??%?→?); #Hc cut (is_endc r1 = true)
403 [ cases (is_endc r1) in Hc; whd in ⊢ (??%?→?); //
404 change with (current ? (niltape ?)) in match (None ?);
405 <nth_vec_map >nth_change_vec // normalize #H destruct (H) ]
406 #Hendr1 cut (xs = xs1)
407 [ lapply Hnotendxs1 lapply Hnotend lapply Hrs_src lapply xs1
408 -Hnotendxs1 -Hnotend -Hrs_src -xs1 elim xs
409 [ * normalize in ⊢ (%→?); //
410 #x2 #xs2 normalize in ⊢ (%→?); #Heq destruct (Heq) #_ #Hnotendxs1
411 lapply (Hnotendxs1 ? (memb_hd …)) >Hend #H destruct (H)
413 [ normalize in ⊢ (%→?); #Heq destruct (Heq) #Hnotendc
414 >Hnotendc in Hendr1; [| @memb_cons @memb_hd ]
415 normalize in ⊢ (%→?); #H destruct (H)
416 | #x3 #xs3 normalize in ⊢ (%→?); #Heq destruct (Heq)
417 #Hnotendc #Hnotendcxs1 @eq_f @IH
418 [ @(cons_injective_r … Heq)
419 | #c0 #Hc0 @Hnotendc cases (orb_true_l … Hc0) -Hc0 #Hc0
421 | @memb_cons @memb_cons // ]
422 | #c #Hc @Hnotendcxs1 @memb_cons // ]
425 | #Hxsxs1 destruct (Hxsxs1) >Hmid_dst %{ls_dst} %{rsj} % //
426 #rsj0 #c >Hrsj #Hrsj0 destruct (Hrsj0)
427 lapply (append_l2_injective … Hrs_src) // #Hrs' destruct (Hrs') %
430 |#Hcomp1 #Hsrc cases (Hsrc ? (refl ??)) -Hsrc #ls0 * #rs0 #Hdst
431 @False_ind lapply (Hcomp1 ?) [%2 %1 %1 >Hmid_src normalize
432 @(not_to_not ??? (\Pf Hceq)) #H destruct //] #Hintape >Hintape in Hc;
433 whd in ⊢(??%?→?); >Hmid_src
434 change with (current ? (niltape ?)) in match (None ?);
435 <nth_vec_map >Hmid_src whd in ⊢ (??%?→?);
436 >(Hnotend c_src) [|@memb_hd]
437 change with (current ? (niltape ?)) in match (None ?);
438 <nth_vec_map >Hmid_src whd in ⊢ (??%?→?); >Hdst normalize #H destruct (H)
444 definition match_m ≝ λsrc,dst,sig,n,is_startc,is_endc.
445 whileTM … (match_step src dst sig n is_startc is_endc)
446 (inr ?? (inr ?? (inl … (inr ?? start_nop)))).
448 definition R_match_m ≝
449 λsrc,dst,sig,n,is_startc,is_endc.λint,outt: Vector (tape sig) (S n).
451 nth src ? int (niltape ?) = midtape sig ls x (xs@end::rs) →
452 (∀c0. memb ? c0 (x::xs) = true → is_endc c0 = false) → is_endc end = true →
453 (∀c0. memb ? c0 (xs@end::rs) = true → is_startc c0 = false) →
454 (current sig (nth dst (tape sig) int (niltape sig)) = None ? → outt = int) ∧
455 (is_startc x = true →
457 nth dst ? int (niltape ?) = midtape sig ls0 x0 rs0 →
458 (∃l,l1.x0::rs0 = l@x::xs@l1 ∧
461 (change_vec ?? int (midtape sig (reverse ? xs@x::ls) end rs) src)
462 (midtape sig ((reverse ? (l@x::xs))@ls0) cj l2) dst) ∨
463 ∀l,l1.x0::rs0 ≠ l@x::xs@l1)).
465 lemma not_sub_list_merge :
466 ∀T.∀a,b:list T. (∀l1.a ≠ b@l1) → (∀t,l,l1.a ≠ t::l@b@l1) → ∀l,l1.a ≠ l@b@l1.
467 #T #a #b #H1 #H2 #l elim l normalize //
470 lemma not_sub_list_merge_2 :
471 ∀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.
472 #T #a #b #t #H1 #H2 #l elim l //
473 #t0 #l1 #IH #l2 cases (true_or_false (t == t0)) #Htt0
474 [ >(\P Htt0) % normalize #H destruct (H) cases (H2 l1 l2) /2/
475 | normalize % #H destruct (H) cases (\Pf Htt0) /2/ ]
479 lemma wsem_match_m : ∀src,dst,sig,n,is_startc,is_endc.
480 src ≠ dst → src < S n → dst < S n →
481 match_m src dst sig n is_startc is_endc ⊫ R_match_m src dst sig n is_startc is_endc.
482 #src #dst #sig #n #is_startc #is_endc #Hneq #Hsrc #Hdst #ta #k #outc #Hloop
483 lapply (sem_while … (sem_match_step src dst sig n is_startc is_endc Hneq Hsrc Hdst) … Hloop) //
484 -Hloop * #tb * #Hstar @(star_ind_l ??????? Hstar) -Hstar
485 [ #Hfalse #ls #x #xs #end #rs #Hmid_src #Hnotend #Hend #Hnotstart
486 cases (Hfalse … Hmid_src Hnotend Hend) -Hfalse
487 [(* current dest = None *) *
488 [ * #Hcur_dst #Houtc %
490 |#Hstart #ls0 #x0 #rs0 #Hmid_dst >Hmid_dst in Hcur_dst;
491 normalize in ⊢ (%→?); #H destruct (H)
493 | * #ls0 * #rs0 * #xs0 * * #Htc_dst #Hrs0 #HNone %
494 [ >Htc_dst normalize in ⊢ (%→?); #H destruct (H)
495 | #Hstart #ls1 #x1 #rs1 >Htc_dst #H destruct (H)
497 [ % %{[ ]} %{[ ]} % [ >append_nil >append_nil %]
498 #cj #ls2 #H destruct (H)
499 | #x2 #xs2 %2 #l #l1 % #Habs lapply (eq_f ?? (length ?) ?? Habs)
500 >length_append whd in ⊢ (??%(??%)→?); >length_append
501 >length_append normalize >commutative_plus whd in ⊢ (???%→?);
502 #H destruct (H) lapply e0 >(plus_n_O (|rs1|)) in ⊢ (??%?→?);
503 >associative_plus >associative_plus
504 #e1 lapply (injective_plus_r ??? e1) whd in ⊢ (???%→?);
509 |* #ls0 * #rs0 * #Hmid_dst #HFalse %
510 [ >Hmid_dst normalize in ⊢ (%→?); #H destruct (H)
511 | #Hstart #ls1 #x1 #rs1 >Hmid_dst #H destruct (H)
512 %1 %{[ ]} %{rs0} % [%] #cj #l2 #Hnotnil
513 >reverse_cons >associative_append @(HFalse ?? Hnotnil)
516 |-ta #ta #tc #Htrue #Hstar #IH #Hout lapply (IH Hout) -IH -Hout #IH whd
517 #ls #x #xs #end #rs #Hmid_src #Hnotend #Hend #Hnotstart
518 lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
519 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→?);
521 [#_ whd in Htrue; >Hmid_src in Htrue; #Htrue
522 cases (Htrue x (refl … )) -Htrue * #Htaneq #_
523 @False_ind >Hmid_dst in Htaneq; /2/
524 |#Hstart #ls0 #x0 #rs0 #Hmid_dst2 >Hmid_dst2 in Hmid_dst; normalize in ⊢ (%→?);
527 | #c #Hcurta_dst % [ >Hcurta_dst #H destruct (H) ]
528 #Hstart #ls0 #x0 #rs0 #Hmid_dst >Hmid_dst in Hcurta_dst; normalize in ⊢ (%→?);
529 #H destruct (H) whd in Htrue; >Hmid_src in Htrue; #Htrue
530 cases (Htrue x (refl …)) -Htrue #_ #Htrue cases (Htrue Hstart Hnotstart) -Htrue
531 cases (true_or_false (x==c)) #eqx
532 [ lapply (\P eqx) -eqx #eqx destruct (eqx)
533 #_ #Htrue cases (comp_list ? (xs@end::rs) rs0 is_endc)
534 #x1 * #tl1 * #tl2 * * * #Hxs #Hrs0 #Hnotendx1
536 [>append_nil #Hx1 <Hx1 in Hnotendx1; #Hnotendx1
537 lapply (Hnotendx1 end ?) [ @memb_append_l2 @memb_hd ]
538 >Hend #H destruct (H) ]
539 #ci -tl1 #tl1 #Hxs #H cases (H … (refl … )) -H
540 [ #Hendci % >Hrs0 in Hmid_dst; cut (ci = end ∧ x1 = xs)
541 [ lapply Hxs lapply Hnotendx1 lapply x1 elim xs in Hnotend;
543 [ #_ normalize #H destruct (H) /2/
544 | #x2 #xs2 #Hnotendx2 normalize #H destruct (H)
545 >(Hnotendx2 ? (memb_hd …)) in Hend; #H destruct (H) ]
546 | #x2 #xs2 #IH #Hnotendx2 *
547 [ #_ normalize #H destruct (H) >(Hnotendx2 ci ?) in Hendci;
549 | @memb_cons @memb_hd ]
550 | #x3 #xs3 #Hnotendx3 normalize #H destruct (H)
553 | #c0 #Hc0 @Hnotendx2 cases (orb_true_l … Hc0) -Hc0 #Hc0
555 | @memb_cons @memb_cons @Hc0 ]
556 | #c0 #Hc0 @Hnotendx3 @memb_cons @Hc0 ]
559 | * #Hcieq #Hx1eq >Hx1eq #Hmid_dst
560 cases (Htrue ??????? (refl ??) Hmid_dst Hnotend)
561 <Hcieq >Hendci * #H destruct (H) ]
563 [ >append_nil #Hrs0 destruct (Hrs0) * #Hcifalse#_ %2
564 cut (∃l.xs = x1@ci::l)
565 [lapply Hxs lapply Hnotendx1 lapply Hnotend lapply xs
566 -Hxs -xs -Hnotendx1 elim x1
568 [ #_ #_ normalize #H1 destruct (H1) >Hend in Hcifalse;
570 | #x2 #xs2 #_ #_ normalize #H >(cons_injective_l ????? H) %{xs2} % ]
572 [ #_ #Hnotendxs2 normalize #H destruct (H)
573 >(Hnotendxs2 ? (memb_hd …)) in Hend; #H destruct (H)
574 | #x3 #xs3 #Hnotendxs3 #Hnotendxs2 normalize #H destruct (H)
576 [ #xs4 #Hxs4 >Hxs4 %{xs4} %
577 | #c0 #Hc0 cases (orb_true_l … Hc0) -Hc0 #Hc0
578 [ >(\P Hc0) @Hnotendxs3 @memb_hd
579 | @Hnotendxs3 @memb_cons @memb_cons @Hc0 ]
580 | #c0 #Hc0 @Hnotendxs2 @memb_cons @Hc0 ]
584 #l0 #l1 % #H lapply (eq_f ?? (length ?) ?? H) -H
585 >length_append normalize >length_append >length_append
586 normalize >commutative_plus normalize #H destruct (H) -H
587 >associative_plus in e0; >associative_plus
588 >(plus_n_O (|x1|)) in ⊢(??%?→?); #H lapply (injective_plus_r … H)
589 -H normalize #H destruct (H)
590 | #cj #tl2' #Hrs0 * #Hcifalse #Hcomp
591 lapply (Htrue ls c x1 ci tl1 ls0 (cj::tl2') ???)
592 [ #c0 #Hc0 cases (orb_true_l … Hc0) #Hc0
593 [ @Hnotend >(\P Hc0) @memb_hd
597 | * * #_ #_ -Htrue #Htrue lapply (Htrue ?? (refl ??) ?) [ @(Hcomp ?? (refl ??)) ]
598 * #Htb >Htb #Hendci >Hrs0 >Hxs
599 cases (IH ls c xs end rs ? Hnotend Hend Hnotstart) -IH
600 [| >Htb >nth_change_vec_neq [|@sym_not_eq //] @Hmid_src ]
601 #_ #IH lapply Hxs lapply Hnotendx1 -Hxs -Hnotendx1 cases x1 in Hrs0;
602 [ #Hrs0 #_ whd in ⊢ (???%→?); #Hxs
603 cases (IH Hstart (c::ls0) cj tl2' ?)
604 [ -IH * #l * #l1 * #Hll1 #IH % %{(c::l)} %{l1}
606 #cj0 #l2 #Hcj0 >(IH … Hcj0) >Htb
607 >change_vec_commute // >change_vec_change_vec
608 >change_vec_commute [|@sym_not_eq // ] @eq_f3 //
609 >reverse_cons >associative_append %
610 | #IH %2 #l #l1 >(?:l@c::xs@l1 = l@(c::xs)@l1) [|%]
612 [ #l2 cut (∃xs'.xs = ci::xs')
614 [ normalize #H destruct (H) >Hend in Hendci; #H destruct (H)
615 | #ci' #xs' normalize #H lapply (cons_injective_l ????? H)
618 * #xs' #Hxs' >Hxs' normalize % #H destruct (H)
619 lapply (Hcomp … (refl ??)) * /2/
620 |#t #l2 #l3 % normalize #H lapply (cons_injective_r ????? H)
621 -H #H >H in IH; #IH cases (IH l2 l3) -IH #IH @IH % ]
622 | >Htb >nth_change_vec // >Hmid_dst >Hrs0 % ]
623 | #x2 #xs2 normalize in ⊢ (%→?); #Hrs0 #Hnotendxs2 normalize in ⊢ (%→?);
624 #Hxs cases (IH Hstart (c::ls0) x2 (xs2@cj::tl2') ?)
625 [ -IH * #l * #l1 * #Hll1 #IH % %{(c::l)} %{l1}
627 #cj0 #l2 #Hcj0 >(IH … Hcj0) >Htb
628 >change_vec_commute // >change_vec_change_vec
629 >change_vec_commute [|@sym_not_eq // ] @eq_f3 //
630 >reverse_cons >associative_append %
631 | -IH #IH %2 #l #l1 >(?:l@c::xs@l1 = l@(c::xs)@l1) [|%]
632 @not_sub_list_merge_2 [| @IH]
633 cut (∃l2.xs = (x2::xs2)@ci::l2)
635 lapply Hnotend -Hnotend lapply Hxs
636 >(?:x2::xs2@ci::tl1 = (x2::xs2)@ci::tl1) [|%]
637 lapply (x2::xs2) elim xs
639 [ normalize in ⊢ (%→?); #H1 destruct (H1)
640 >Hendci in Hend; #Hend destruct (Hend)
641 | #x3 #xs3 normalize in ⊢ (%→?); #H1 destruct (H1)
642 #_ #Hnotendx3 >(Hnotendx3 ? (memb_hd …)) in Hend;
643 #Hend destruct (Hend)
646 [ normalize in ⊢ (%→?); #Hxs3 destruct (Hxs3) #_ #_
648 | #x4 #xs4 normalize in ⊢ (%→?); #Hxs3xs4 #Hnotend
649 #Hnotendxs4 destruct (Hxs3xs4) cases (IHin ? e0 ??)
650 [ #l0 #Hxs3 >Hxs3 %{l0} %
651 | #c0 #Hc0 @Hnotend cases (orb_true_l … Hc0) -Hc0 #Hc0
653 | @memb_cons @memb_cons @Hc0 ]
654 | #c0 #Hc0 @Hnotendxs4 @memb_cons //
659 >Hxs' #l3 normalize >associative_append normalize % #H
660 destruct (H) lapply (append_l2_injective ?????? e1) //
661 #H1 destruct (H1) cases (Hcomp ?? (refl ??)) /2/
662 | >Htb >nth_change_vec // >Hmid_dst >Hrs0 % ]
667 |lapply (\Pf eqx) -eqx #eqx >Hmid_dst #Htrue
668 cases (Htrue ? (refl ??) eqx) -Htrue #Htb #Hendcx #_
670 [ #_ %2 #l #l1 cases l
673 [ normalize % #H destruct (H) cases eqx /2/
674 | #tmp1 #l2 normalize % #H destruct (H) ]
675 | #tmp1 #l2 normalize % #H destruct (H) ]
676 | #tmp1 #l2 normalize % #H destruct (H)cases l2 in e0;
677 [ normalize #H1 destruct (H1)
678 | #tmp2 #l3 normalize #H1 destruct (H1) ]
680 | #r1 #rs1 normalize in ⊢ (???(????%?)→?); #Htb >Htb in IH; #IH
681 cases (IH ls x xs end rs ? Hnotend Hend Hnotstart)
682 [| >Htb >nth_change_vec_neq [|@sym_not_eq //] @Hmid_src ] -IH
683 #_ #IH cases (IH Hstart (c::ls0) r1 rs1 ?)
684 [|| >nth_change_vec // ] -IH
685 [ * #l * #l1 * #Hll1 #Hout % %{(c::l)} %{l1} % >Hll1 //
686 >reverse_cons >associative_append #cj0 #ls #Hl1 >(Hout ?? Hl1)
687 >change_vec_commute in ⊢ (??(???%??)?); // @sym_not_eq //
688 | #IH %2 @(not_sub_list_merge_2 ?? (x::xs)) normalize [|@IH]
689 #l1 % #H destruct (H) cases eqx /2/
696 definition Pre_match_m ≝
697 λsrc,sig,n,is_startc,is_endc.λt: Vector (tape sig) (S n).
699 nth src (tape sig) t (niltape sig) = midtape ? [] start (xs@[end]) ∧
700 is_startc start = true ∧
701 (∀c.c ∈ (xs@[end]) = true → is_startc c = false) ∧
702 (∀c.c ∈ (start::xs) = true → is_endc c = false) ∧
705 lemma terminate_match_m :
706 ∀src,dst,sig,n,is_startc,is_endc,t.
707 src ≠ dst → src < S n → dst < S n →
708 Pre_match_m src sig n is_startc is_endc t →
709 match_m src dst sig n is_startc is_endc ↓ t.
710 #src #dst #sig #n #is_startc #is_endc #t #Hneq #Hsrc #Hdst * #start * #xs * #end
711 * * * * #Hmid_src #Hstart #Hnotstart #Hnotend #Hend
712 @(terminate_while … (sem_match_step src dst sig n is_startc is_endc Hneq Hsrc Hdst)) //
713 <(change_vec_same … t dst (niltape ?))
714 lapply (refl ? (nth dst (tape sig) t (niltape ?)))
715 cases (nth dst (tape sig) t (niltape ?)) in ⊢ (???%→?);
716 [ #Htape_dst % #t1 whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
717 >Hmid_src #HR cases (HR ? (refl ??)) -HR
718 >nth_change_vec // >Htape_dst normalize in ⊢ (%→?);
720 | #x0 #xs0 #Htape_dst % #t1 whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
721 >Hmid_src #HR cases (HR ? (refl ??)) -HR
722 >nth_change_vec // >Htape_dst normalize in ⊢ (%→?);
724 | #x0 #xs0 #Htape_dst % #t1 whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
725 >Hmid_src #HR cases (HR ? (refl ??)) -HR
726 >nth_change_vec // >Htape_dst normalize in ⊢ (%→?);
728 | #ls #s #rs lapply s -s lapply ls -ls lapply Hmid_src lapply t -t elim rs
729 [#t #Hmid_src #ls #s #Hmid_dst % #t1 whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
730 >Hmid_src >nth_change_vec // >Hmid_dst #HR cases (HR ? (refl ??)) -HR #_
731 #HR cases (HR Hstart Hnotstart)
732 cases (true_or_false (start == s)) #Hs
733 [ lapply (\P Hs) -Hs #Hs <Hs #_ #Htrue
734 cut (∃ci,xs1.xs@[end] = ci::xs1)
737 | #x1 #xs1 %{x1} %{(xs1@[end])} % ] ] * #ci * #xs1 #Hxs
738 >Hxs in Htrue; #Htrue
739 cases (Htrue [ ] start [ ] ? xs1 ? [ ] (refl ??) (refl ??) ?)
740 [ * #_ * #H @False_ind @H % ]
741 #c0 #Hc0 @Hnotend >(memb_single … Hc0) @memb_hd
742 | lapply (\Pf Hs) -Hs #Hs #Htrue #_
743 cases (Htrue ? (refl ??) Hs) -Htrue #Ht1 #_ %
744 #t2 whd in ⊢ (%→?); #HR cases (HR start ?)
745 [ >Ht1 >nth_change_vec // normalize in ⊢ (%→?); * #H @False_ind @H %
746 | >Ht1 >nth_change_vec_neq [|@sym_not_eq //]
747 >nth_change_vec_neq [|@sym_not_eq //] >Hmid_src % ]
749 |#r0 #rs0 #IH #t #Hmid_src #ls #s #Hmid_dst % #t1 whd in ⊢ (%→?);
750 >nth_change_vec_neq [|@sym_not_eq //] >Hmid_src
751 #Htrue cases (Htrue ? (refl ??)) -Htrue #_ #Htrue
752 <(change_vec_same … t1 dst (niltape ?))
753 cases (Htrue Hstart Hnotstart) -Htrue
754 cases (true_or_false (start == s)) #Hs
755 [ lapply (\P Hs) -Hs #Hs <Hs #_ #Htrue
756 cut (∃ls0,xs0,ci,rs,rs0.
757 nth src ? t (niltape ?) = midtape sig [ ] start (xs0@ci::rs) ∧
758 nth dst ? t (niltape ?) = midtape sig ls0 s (xs0@rs0) ∧
759 (is_endc ci = true ∨ (is_endc ci = false ∧ (∀b,tlb.rs0 = b::tlb → ci ≠ b))))
760 [cases (comp_list ? (xs@[end]) (r0::rs0) is_endc) #xs0 * #xs1 * #xs2
761 * * * #Hxs #Hrs #Hxs0notend #Hcomp >Hrs
762 cut (∃y,ys. xs1 = y::ys)
763 [ lapply Hxs0notend lapply Hxs lapply xs0 elim xs
765 [ normalize #Hxs1 <Hxs1 #_ %{end} %{[]} %
766 | #z #zs normalize in ⊢ (%→?); #H destruct (H) #H
767 lapply (H ? (memb_hd …)) -H >Hend #H1 destruct (H1)
770 [ normalize in ⊢ (%→?); #Hxs1 <Hxs1 #_ %{y} %{(ys@[end])} %
771 | #z #zs normalize in ⊢ (%→?); #H destruct (H) #Hmemb
772 @(IH0 ? e0 ?) #c #Hc @Hmemb @memb_cons // ] ] ] * #y * #ys #Hxs1
773 >Hxs1 in Hxs; #Hxs >Hmid_src >Hmid_dst >Hxs >Hrs
774 %{ls} %{xs0} %{y} %{ys} %{xs2}
775 % [ % // | @Hcomp // ] ]
776 * #ls0 * #xs0 * #ci * #rs * #rs0 * * #Hmid_src' #Hmid_dst' #Hcomp
777 <Hmid_src in Htrue; >nth_change_vec // >Hs #Htrue destruct (Hs)
778 lapply (Htrue ??????? Hmid_src' Hmid_dst' ?) -Htrue
779 [ #c0 #Hc0 @Hnotend cases (orb_true_l … Hc0) -Hc0 #Hc0
780 [ whd in ⊢ (??%?); >Hc0 %
781 | @memb_cons >Hmid_src in Hmid_src'; #Hmid_src' destruct (Hmid_src')
782 lapply e0 -e0 @(list_elim_left … rs)
783 [ #e0 destruct (e0) lapply (append_l1_injective_r ?????? e0) //
784 | #x1 #xs1 #_ >append_cons in ⊢ (???%→?);
785 <associative_append #e0 lapply (append_l1_injective_r ?????? e0) //
786 #e1 >e1 @memb_append_l1 @memb_append_l1 // ] ]
787 | * * #Hciendc cases rs0 in Hcomp;
788 [ #_ * #H @False_ind @H %
789 | #r1 #rs1 * [ >Hciendc #H destruct (H) ]
790 * #_ #Hcomp lapply (Hcomp ?? (refl ??)) -Hcomp #Hcomp #_ #Htrue
791 cases (Htrue ?? (refl ??) Hcomp) #Ht1 #_ >Ht1 @(IH ?? (s::ls) r0)
792 [ >nth_change_vec_neq [|@sym_not_eq //]
793 >nth_change_vec_neq [|@sym_not_eq //] @Hmid_src
794 | >nth_change_vec // >Hmid_dst % ] ] ]
795 | >Hmid_dst >nth_change_vec // lapply (\Pf Hs) -Hs #Hs #Htrue #_
796 cases (Htrue ? (refl ??) Hs) #Ht1 #_ >Ht1 @(IH ?? (s::ls) r0)
797 [ >nth_change_vec_neq [|@sym_not_eq //]
798 >nth_change_vec_neq [|@sym_not_eq //] @Hmid_src
799 | >nth_change_vec // ] ] ] ]