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 →
134 definition R_rewind ≝ λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
136 nth src ? int (niltape ?) = midtape sig (xs@[x0]) x rs →
137 ∀ls0,y,y0,target,rs0.|xs| = |target| →
138 nth dst ? int (niltape ?) = midtape sig (target@y0::ls0) y rs0 →
140 (change_vec ?? int (midtape sig [] x0 (reverse ? xs@x::rs)) src)
141 (midtape sig ls0 y0 (reverse ? target@y::rs0)) dst) ∧
142 (∀x,rs.nth src ? int (niltape ?) = midtape sig [] x rs →
143 ∀ls0,y,rs0.nth dst ? int (niltape ?) = midtape sig ls0 y rs0 →
147 theorem accRealize_to_Realize :
148 ∀sig,n.∀M:mTM sig n.∀Rtrue,Rfalse,acc.
149 M ⊨ [ acc: Rtrue, Rfalse ] → M ⊨ Rtrue ∪ Rfalse.
150 #sig #n #M #Rtrue #Rfalse #acc #HR #t
151 cases (HR t) #k * #outc * * #Hloop
152 #Htrue #Hfalse %{k} %{outc} % //
153 cases (true_or_false (cstate sig (states sig n M) n outc == acc)) #Hcase
154 [ % @Htrue @(\P Hcase) | %2 @Hfalse @(\Pf Hcase) ]
158 lemma sem_rewind_strong : ∀src,dst,sig,n.
159 src ≠ dst → src < S n → dst < S n →
160 rewind src dst sig n ⊨ R_rewind_strong src dst sig n.
161 #src #dst #sig #n #Hneq #Hsrc #Hdst
162 @(sem_seq_app sig n ????? (sem_parmoveL src dst sig n Hneq Hsrc Hdst) ?)
163 [| @(sem_seq_app sig n ????? (sem_move_multi … R ?) (sem_move_multi … R ?)) //
165 #ta #tb * #tc * * * #Htc1 #Htc2 #_ * #td * whd in ⊢ (%→%→?); #Htd #Htb % [ %
166 [ #x #x0 #xs #rs #Hmidta_src #ls0 #y #y0 #target #rs0 #Hlen #Hmidta_dst
167 >(Htc1 ??? Hmidta_src ls0 y (target@[y0]) rs0 ??) in Htd;
169 |>length_append >length_append >Hlen % ]
170 >change_vec_commute [|@sym_not_eq //]
171 >change_vec_change_vec
172 >nth_change_vec_neq [|@sym_not_eq //]
173 >nth_change_vec // >reverse_append >reverse_single
174 >reverse_append >reverse_single normalize in match (tape_move ???);
175 >rev_append_def >append_nil #Htd >Htd in Htb;
176 >change_vec_change_vec >nth_change_vec //
177 cases ls0 [|#l1 #ls1] normalize in match (tape_move ???); //
178 | #x #x0 #xs #rs #Hmidta_dst #ls0 #y #y0 #target #rs0 #Hlen #Hmidta_src
179 >(Htc2 ??? Hmidta_dst ls0 y (target@[y0]) rs0 ??) in Htd;
181 |>length_append >length_append >Hlen % ]
182 >change_vec_change_vec
183 >change_vec_commute [|@sym_not_eq //]
185 >reverse_append >reverse_single
186 >reverse_append >reverse_single
187 cases ls0 [|#l1 #ls1] normalize in match (tape_move ???);
188 #Htd >Htd in Htb; >change_vec_change_vec >nth_change_vec //
189 >rev_append_def >change_vec_commute // normalize in match (tape_move ???); // ]
190 | #x #rs #Hmidta_src #ls0 #y #rs0 #Hmidta_dst
191 lapply (Htc1 … Hmidta_src … (refl ??) Hmidta_dst) -Htc1 #Htc >Htc in Htd;
192 >change_vec_commute [|@sym_not_eq //] >change_vec_change_vec
193 >nth_change_vec_neq [|@sym_not_eq //]
194 >nth_change_vec // lapply (refl ? ls0) cases ls0 in ⊢ (???%→%);
195 [ #Hls0 #Htd >Htd in Htb;
196 >nth_change_vec // >change_vec_change_vec
197 whd in match (tape_move ???);whd in match (tape_move ???); <Hmidta_src
198 <Hls0 <Hmidta_dst >change_vec_same >change_vec_same //
199 | #l1 #ls1 #Hls0 #Htd >Htd in Htb;
200 >nth_change_vec // >change_vec_change_vec
201 whd in match (tape_move ???);whd in match (tape_move ???); <Hmidta_src
202 <Hls0 <Hmidta_dst >change_vec_same >change_vec_same //
206 lemma sem_rewind : ∀src,dst,sig,n.
207 src ≠ dst → src < S n → dst < S n →
208 rewind src dst sig n ⊨ R_rewind src dst sig n.
209 #src #dst #sig #n #Hneq #Hsrc #Hdst @(Realize_to_Realize … (sem_rewind_strong …)) //
210 #ta #tb * * #H1 #H2 #H3 % /2/
213 definition match_step ≝ λsrc,dst,sig,n.
214 compare src dst sig n ·
215 (ifTM ?? (partest sig n (match_test src dst sig ?))
217 (rewind src dst sig n · (inject_TM ? (move_r ?) n dst)))
221 (* we assume the src is a midtape
223 if the dst is out of bounds (outt = int)
224 or dst.right is shorter than src.right (outt.current → None)
225 or src.right is a prefix of dst.right (out = just right of the common prefix) *)
226 definition R_match_step_false ≝
227 λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
229 nth src ? int (niltape ?) = midtape sig ls x xs →
230 ((current sig (nth dst (tape sig) int (niltape sig)) = None ?) ∧ outt = int) ∨
231 (∃ls0,rs0,xs0. nth dst ? int (niltape ?) = midtape sig ls0 x rs0 ∧
234 (change_vec ?? int (mk_tape sig (reverse ? rs0@x::ls) (option_hd ? xs0) (tail ? xs0)) src)
235 (mk_tape ? (reverse ? rs0@x::ls0) (None ?) [ ]) dst) ∨
237 nth dst ? int (niltape ?) = midtape sig ls0 x (xs@rs0) ∧
241 (change_vec ?? int (mk_tape sig (reverse ? xs@x::ls) (None ?) [ ]) src)
242 (mk_tape sig (reverse ? xs@x::ls0) (option_hd ? rs0) (tail ? rs0)) dst).
245 we assume the src is a midtape [ ] s rs
247 then dst.current = Some ? s1
248 and if s ≠ s1 then outt = int.dst.move_right()
250 then int.src.right and int.dst.right have a common prefix
251 and the heads of their suffixes are different
252 and outt = int.dst.move_right().
255 definition R_match_step_true ≝
256 λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
257 ∀s,rs.nth src ? int (niltape ?) = midtape ? [ ] s rs →
258 outt = change_vec ?? int
259 (tape_move_mono … (nth dst ? int (niltape ?)) (〈None ?,R〉)) dst ∧
260 (∃s0.current sig (nth dst (tape sig) int (niltape sig)) = Some ? s0 ∧
262 ∃xs,ci,rs',ls0,cj,rs0.
264 nth dst ? int (niltape ?) = midtape sig ls0 s (xs@cj::rs0) ∧
267 lemma sem_match_step :
268 ∀src,dst,sig,n.src ≠ dst → src < S n → dst < S n →
269 match_step src dst sig n ⊨
270 [ inr ?? (inr ?? (inl … (inr ?? start_nop))) :
271 R_match_step_true src dst sig n,
272 R_match_step_false src dst sig n ].
273 #src #dst #sig #n #Hneq #Hsrc #Hdst
274 @(acc_sem_seq_app sig n … (sem_compare src dst sig n Hneq Hsrc Hdst)
275 (acc_sem_if ? n … (sem_partest sig n (match_test src dst sig ?))
277 (sem_rewind ???? Hneq Hsrc Hdst)
278 (sem_inject … dst (le_S_S_to_le … Hdst) (sem_move_r ? )))
280 [ #ta #tb #tc * lapply (refl ? (current ? (nth src ? ta (niltape ?))))
281 cases (current ? (nth src ? ta (niltape ?))) in ⊢ (???%→%);
282 [ #Hcurta_src #Hcomp #_ * #td * >Hcomp [| % %2 %]
283 whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
284 >nth_current_chars >Hcurta_src normalize in ⊢ (%→?); #H destruct (H)
285 | #s #Hs lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
286 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→%);
287 [ #Hcurta_dst #Hcomp #_ * #td * >Hcomp [| %2 %]
288 whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
289 >nth_current_chars >nth_current_chars >Hs >Hcurta_dst
290 normalize in ⊢ (%→?); #H destruct (H)
292 cases (current_to_midtape … Hs) #ls * #rs #Hmidta_src >Hmidta_src
293 cases (current_to_midtape … Hs0) #ls0 * #rs0 #Hmidta_dst >Hmidta_dst
294 cases (true_or_false (s == s0)) #Hss0
295 [ lapply (\P Hss0) -Hss0 #Hss0 destruct (Hss0)
296 #_ #Hcomp cases (Hcomp ????? (refl ??) (refl ??)) -Hcomp [ *
297 [ * #rs' * #_ #Hcurtc_dst * #td * whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
298 >nth_current_chars >nth_current_chars >Hcurtc_dst
299 cases (current ? (nth src …))
300 [normalize in ⊢ (%→?); #H destruct (H)
301 | #x >nth_change_vec // cases (reverse ? rs0)
302 [ normalize in ⊢ (%→?); #H destruct (H)
303 | #r1 #rs1 normalize in ⊢ (%→?); #H destruct (H) ] ]
304 | * #rs0' * #_ #Hcurtc_src * #td * whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
305 >(?:nth src ? (current_chars ?? tc) (None ?) = None ?)
306 [|>nth_current_chars >Hcurtc_src >nth_change_vec_neq
307 [>nth_change_vec [cases (append ???) // | @Hsrc]
308 |@(not_to_not … Hneq) //
310 normalize in ⊢ (%→?); #H destruct (H) ]
311 | * #xs * #ci * #cj * #rs'' * #rs0' * * * #Hcicj #Hrs #Hrs0
312 #Htc * #td * * #Hmatch #Htd destruct (Htd) * #te * *
313 >Htc >change_vec_commute // >nth_change_vec //
314 >change_vec_commute [|@sym_not_eq //] >nth_change_vec // #Hte #_ #Htb
315 #s' #rs' >Hmidta_src #H destruct (H)
316 lapply (Hte … (refl ??) … (refl ??) (refl ??)) -Hte
317 >change_vec_commute // >change_vec_change_vec
318 >change_vec_commute [|@sym_not_eq //] >change_vec_change_vec #Hte
319 >Hte in Htb; * * #_ >nth_change_vec // #Htb1
320 lapply (Htb1 … (refl ??)) -Htb1 #Htb1 #Htb2 %
321 [ @(eq_vec … (niltape ?)) #i #Hi
322 cases (true_or_false ((dst : DeqNat) == i)) #Hdsti
323 [ <(\P Hdsti) >Htb1 >nth_change_vec // >Hmidta_dst
324 >Hrs0 >reverse_reverse cases xs [|#r1 #rs1] %
325 | <Htb2 [|@(\Pf Hdsti)] >nth_change_vec_neq [| @(\Pf Hdsti)]
326 >Hrs0 >reverse_reverse >nth_change_vec_neq in ⊢ (???%);
327 <Hrs <Hmidta_src [|@(\Pf Hdsti)] >change_vec_same % ]
328 | >Hmidta_dst %{s'} % [%] #_
329 >Hrs0 %{xs} %{ci} %{rs''} %{ls0} %{cj} %{rs0'} % // % //
332 | lapply (\Pf Hss0) -Hss0 #Hss0 #Htc cut (tc = ta)
333 [@Htc % % @(not_to_not ??? Hss0) #H destruct (H) %]
334 -Htc #Htc destruct (Htc) #_ * #td * whd in ⊢ (%→?); * #_
335 #Htd destruct (Htd) * #te * * #_ #Hte * * #_ #Htb1 #Htb2
336 #s1 #rs1 >Hmidta_src #H destruct (H)
337 lapply (Hte … Hmidta_src … Hmidta_dst) -Hte #Hte destruct (Hte) %
338 [ @(eq_vec … (niltape ?)) #i #Hi
339 cases (true_or_false ((dst : DeqNat) == i)) #Hdsti
340 [ <(\P Hdsti) >(Htb1 … Hmidta_dst) >nth_change_vec // >Hmidta_dst
341 cases rs0 [|#r2 #rs2] %
342 | <Htb2 [|@(\Pf Hdsti)] >nth_change_vec_neq [| @(\Pf Hdsti)] % ]
343 | >Hs0 %{s0} % // #H destruct (H) @False_ind cases (Hss0) /2/ ]
347 | #ta #tb #tc * #Hcomp1 #Hcomp2 * #td * * #Htest #Htd destruct (Htd)
348 whd in ⊢ (%→?); #Htb destruct (Htb) #ls #x #xs #Hta_src
349 lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
350 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→?);
351 [ #Hcurta_dst % % % // @Hcomp1 %2 //
352 | #x0 #Hcurta_dst cases (current_to_midtape … Hcurta_dst) -Hcurta_dst
353 #ls0 * #rs0 #Hta_dst cases (true_or_false (x == x0)) #Hxx0
354 [ lapply (\P Hxx0) -Hxx0 #Hxx0 destruct (Hxx0)
355 | >(?:tc=ta) in Htest;
356 [|@Hcomp1 % % >Hta_src >Hta_dst @(not_to_not ??? (\Pf Hxx0)) normalize
357 #Hxx0' destruct (Hxx0') % ]
359 >nth_current_chars >Hta_src >nth_current_chars >Hta_dst
360 whd in ⊢ (??%?→?); #Hfalse destruct (Hfalse) ] -Hcomp1
361 cases (Hcomp2 … Hta_src Hta_dst) [ *
362 [ * #rs' * #Hxs #Hcurtc % %2 %{ls0} %{rs0} %{rs'} %
364 | * #rs0' * #Hxs #Htc %2 >Htc %{ls0} %{rs0'} % // ]
365 | * #xs0 * #ci * #cj * #rs' * #rs0' * * *
366 #Hci #Hxs #Hrs0 #Htc @False_ind
368 >(?:nth src ? (current_chars ?? tc) (None ?) = Some ? ci) in Htest;
369 [|>nth_current_chars >Htc >nth_change_vec_neq [|@(not_to_not … Hneq) //]
371 >(?:nth dst ? (current_chars ?? tc) (None ?) = Some ? cj)
372 [|>nth_current_chars >Htc >nth_change_vec //]
373 normalize #H destruct (H) ] ] ]
376 definition match_m ≝ λsrc,dst,sig,n.
377 whileTM … (match_step src dst sig n)
378 (inr ?? (inr ?? (inl … (inr ?? start_nop)))).
380 definition R_match_m ≝
381 λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
383 nth src ? int (niltape ?) = midtape sig [ ] x rs →
384 (current sig (nth dst (tape sig) int (niltape sig)) = None ? →
385 right ? (nth dst (tape sig) int (niltape sig)) = [ ] → outt = int) ∧
387 nth dst ? int (niltape ?) = midtape sig ls0 x0 rs0 →
388 (∃l,l1.x0::rs0 = l@x::rs@l1 ∧
391 (mk_tape sig (reverse ? rs@[x]) (None ?) [ ]) src)
392 (mk_tape sig ((reverse ? (l@x::rs))@ls0) (option_hd ? l1) (tail ? l1)) dst) ∨
393 ∀l,l1.x0::rs0 ≠ l@x::rs@l1).
395 lemma not_sub_list_merge :
396 ∀T.∀a,b:list T. (∀l1.a ≠ b@l1) → (∀t,l,l1.a ≠ t::l@b@l1) → ∀l,l1.a ≠ l@b@l1.
397 #T #a #b #H1 #H2 #l elim l normalize //
400 lemma not_sub_list_merge_2 :
401 ∀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.
402 #T #a #b #t #H1 #H2 #l elim l //
403 #t0 #l1 #IH #l2 cases (true_or_false (t == t0)) #Htt0
404 [ >(\P Htt0) % normalize #H destruct (H) cases (H2 l1 l2) /2/
405 | normalize % #H destruct (H) cases (\Pf Htt0) /2/ ]
409 lemma wsem_match_m : ∀src,dst,sig,n.
410 src ≠ dst → src < S n → dst < S n →
411 match_m src dst sig n ⊫ R_match_m src dst sig n.
412 #src #dst #sig #n #Hneq #Hsrc #Hdst #ta #k #outc #Hloop
413 lapply (sem_while … (sem_match_step src dst sig n Hneq Hsrc Hdst) … Hloop) //
414 -Hloop * #tb * #Hstar @(star_ind_l ??????? Hstar) -Hstar
415 [ #Hfalse #x #xs #Hmid_src
416 cases (Hfalse … Hmid_src) -Hfalse
417 [(* current dest = None *) *
418 [ * #Hcur_dst #Houtc %
420 | #ls0 #x0 #rs0 #Hmid_dst >Hmid_dst in Hcur_dst;
421 normalize in ⊢ (%→?); #H destruct (H)
423 | * #ls0 * #rs0 * #xs0 * * #Htc_dst #Hrs0 #HNone %
424 [ >Htc_dst normalize in ⊢ (%→?); #H destruct (H)
425 | #ls1 #x1 #rs1 >Htc_dst #H destruct (H)
426 >Hrs0 >HNone cases xs0
427 [ % %{[ ]} %{[ ]} % [ >append_nil >append_nil %]
430 | >reverse_append >reverse_cons >reverse_append
431 >associative_append >associative_append % ]
432 | #x2 #xs2 %2 #l #l1 % #Habs lapply (eq_f ?? (length ?) ?? Habs)
433 >length_append whd in ⊢ (??%(??%)→?); >length_append
434 >length_append normalize >commutative_plus whd in ⊢ (???%→?);
435 #H destruct (H) lapply e0 >(plus_n_O (|rs1|)) in ⊢ (??%?→?);
436 >associative_plus >associative_plus
437 #e1 lapply (injective_plus_r ??? e1) whd in ⊢ (???%→?);
442 |* #ls0 * #rs0 * #Hmid_dst #Houtc %
443 [ >Hmid_dst normalize in ⊢ (%→?); #H destruct (H)
444 |#ls1 #x1 #rs1 >Hmid_dst #H destruct (H)
445 %1 %{[ ]} %{rs0} % [%]
446 >reverse_cons >associative_append >Houtc %
449 |-ta #ta #tc #Htrue #Hstar #IH #Hout lapply (IH Hout) -IH -Hout #IH whd
451 lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
452 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→?);
454 [#Hcurta_dst #Hrightta_dst whd in Htrue; >Hmidta_src in Htrue; #Htrue
455 cases (Htrue ?? (refl ??)) -Htrue #Htc
457 [ >Htc whd in match (tape_move_mono ???); whd in match (tape_write ???);
458 <(change_vec_same … ta dst (niltape ?)) in ⊢ (???%);
459 lapply Hrightta_dst lapply Hcurta_dst -Hrightta_dst -Hcurta_dst
460 cases (nth dst ? ta (niltape ?))
462 | #r0 #rs0 #_ normalize in ⊢ (%→?); #H destruct (H)
464 | #ls #x0 #rs normalize in ⊢ (%→?); #H destruct (H) ] ]
465 -Htc #Htc destruct (Htc) #_
466 cases (IH … Hmidta_src) #Houtc #_ @Houtc //
467 |#ls0 #x0 #rs0 #Hmidta_dst >Hmidta_dst in Hcurta_dst;
468 normalize in ⊢ (%→?); #H destruct (H)
470 | #c #Hcurta_dst % [ >Hcurta_dst #H destruct (H) ]
471 #ls0 #x0 #rs0 #Hmidta_dst >Hmidta_dst in Hcurta_dst; normalize in ⊢ (%→?);
472 #H destruct (H) whd in Htrue; >Hmidta_src in Htrue; #Htrue
473 cases (Htrue ?? (refl …)) -Htrue >Hmidta_dst #Htc
474 cases (true_or_false (x==c)) #eqx
475 [ lapply (\P eqx) -eqx #eqx destruct (eqx) * #s0 * whd in ⊢ (??%?→?); #Hs0
476 destruct (Hs0) #Htrue cases (Htrue (refl ??)) -Htrue
477 #xs0 * #ci * #rs' * #ls1 * #cj * #rs1 * * #Hxs #H destruct (H) #Hcicj
478 >Htc in IH; whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
479 #IH cases (IH … Hmidta_src) -IH #_ >nth_change_vec //
480 cut (∃x1,xs1.xs0@cj::rs1 = x1::xs1)
481 [ cases xs0 [ %{cj} %{rs1} % | #x1 #xs1 %{x1} %{(xs1@cj::rs1)} % ] ] * #x1 * #xs1
482 #Hxs1 >Hxs1 #IH cases (IH … (refl ??)) -IH
483 [ * #l * #l1 * #Hxs1'
484 >change_vec_commute // >change_vec_change_vec
485 #Houtc % %{(s0::l)} %{l1} %
487 | >reverse_cons >associative_append >change_vec_commute // @Houtc ]
488 | #H %2 #l #l1 >(?:l@s0::xs@l1 = l@(s0::xs)@l1) [|%]
490 [ #l2 >Hxs <Hxs1 % normalize #H1 lapply (cons_injective_r ????? H1)
491 >associative_append #H2 lapply (append_l2_injective ????? (refl ??) H2)
492 #H3 lapply (cons_injective_l ????? H3) #H3 >H3 in Hcicj; * /2/
493 |#t #l2 #l3 % normalize #H1 lapply (cons_injective_r ????? H1)
494 -H1 #H1 cases (H l2 l3) #H2 @H2 @H1
497 | #_ cases (IH x xs ?) -IH
498 [| >Htc >nth_change_vec_neq [|@sym_not_eq //] @Hmidta_src ]
499 >Htc >nth_change_vec // cases rs0
500 [ #_ #_ %2 #l #l1 cases l
503 [ normalize % #H destruct (H) cases (\Pf eqx) /2/
504 | #tmp1 #l2 normalize % #H destruct (H) ]
505 | #tmp1 #l2 normalize % #H destruct (H) ]
506 | #tmp1 #l2 normalize % #H destruct (H)cases l2 in e0;
507 [ normalize #H1 destruct (H1)
508 | #tmp2 #l3 normalize #H1 destruct (H1) ] ]
509 | #r1 #rs1 #_ #IH cases (IH … (refl ??)) -IH
510 [ * #l * #l1 * #Hll1 #Houtc % %{(c::l)} %{l1} % [ >Hll1 % ]
511 >Houtc >change_vec_commute // >change_vec_change_vec
512 >change_vec_commute [|@sym_not_eq //]
513 >reverse_cons >associative_append %
514 | #Hll1 %2 @(not_sub_list_merge_2 ?? (x::xs)) normalize [|@Hll1]
515 #l1 % #H destruct (H) cases (\Pf eqx) /2/
523 axiom daemon : ∀P:Prop.P.
525 definition R_match_step_true_naive ≝
526 λsrc,dst,sig,n.λint,outt: Vector (tape sig) (S n).
527 |left ? (nth src ? outt (niltape ?))| +
528 |right ? (nth dst ? outt (niltape ?))| <
529 |left ? (nth src ? int (niltape ?))| +
530 |right ? (nth dst ? int (niltape ?))|.
532 axiom right_mk_tape : ∀sig,ls,c,rs.right ? (mk_tape sig ls c rs) = rs.
533 axiom left_mk_tape : ∀sig,ls,c,rs.left ? (mk_tape sig ls c rs) = ls.
534 axiom length_tail : ∀A,l.0 < |l| → |tail A l| < |l|.
535 axiom lists_length_split :
536 ∀A.∀l1,l2:list A.(∃la,lb.(|la| = |l1| ∧ l2 = la@lb) ∨ (|la| = |l2| ∧ l1 = la@lb)).
538 lemma sem_match_step_termination :
539 ∀src,dst,sig,n.src ≠ dst → src < S n → dst < S n →
540 match_step src dst sig n ⊨
541 [ inr ?? (inr ?? (inl … (inr ?? start_nop))) :
542 R_match_step_true_naive src dst sig n,
543 R_match_step_false src dst sig n ].
544 #src #dst #sig #n #Hneq #Hsrc #Hdst
545 @(acc_sem_seq_app sig n … (sem_compare src dst sig n Hneq Hsrc Hdst)
546 (acc_sem_if ? n … (sem_partest sig n (match_test src dst sig ?))
548 (sem_rewind_strong ???? Hneq Hsrc Hdst)
549 (sem_inject … dst (le_S_S_to_le … Hdst) (sem_move_r ? )))
551 [ #ta #tb #tc * lapply (refl ? (current ? (nth src ? ta (niltape ?))))
552 cases (current ? (nth src ? ta (niltape ?))) in ⊢ (???%→%);
553 [ #Hcurta_src #Hcomp #_ * #td * >Hcomp [| % %2 %]
554 whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
555 >nth_current_chars >Hcurta_src normalize in ⊢ (%→?); #H destruct (H)
556 | #s #Hs lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
557 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→%);
558 [ #Hcurta_dst #Hcomp #_ * #td * >Hcomp [| %2 %]
559 whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
560 >nth_current_chars >nth_current_chars >Hs >Hcurta_dst
561 normalize in ⊢ (%→?); #H destruct (H)
563 cases (current_to_midtape … Hs) #ls * #rs #Hmidta_src >Hmidta_src
564 cases (current_to_midtape … Hs0) #ls0 * #rs0 #Hmidta_dst >Hmidta_dst
565 cases (true_or_false (s == s0)) #Hss0
566 [ lapply (\P Hss0) -Hss0 #Hss0 destruct (Hss0)
567 #_ #Hcomp cases (Hcomp ????? (refl ??) (refl ??)) -Hcomp [ *
568 [ * #rs' * #_ #Hcurtc_dst * #td * whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
569 >nth_current_chars >nth_current_chars >Hcurtc_dst
570 cases (current ? (nth src …))
571 [normalize in ⊢ (%→?); #H destruct (H)
572 | #x >nth_change_vec // cases (reverse ? rs0)
573 [ normalize in ⊢ (%→?); #H destruct (H)
574 | #r1 #rs1 normalize in ⊢ (%→?); #H destruct (H) ] ]
575 | * #rs0' * #_ #Hcurtc_src * #td * whd in ⊢ (%→?); * whd in ⊢ (??%?→?);
576 >(?:nth src ? (current_chars ?? tc) (None ?) = None ?)
577 [|>nth_current_chars >Hcurtc_src >nth_change_vec_neq
578 [>nth_change_vec [cases (append ???) // | @Hsrc]
579 |@(not_to_not … Hneq) //
581 normalize in ⊢ (%→?); #H destruct (H) ]
582 | * #xs * #ci * #cj * #rs'' * #rs0' * * * #Hcicj #Hrs #Hrs0
583 #Htc * #td * * #Hmatch #Htd destruct (Htd) * #te * *
584 >Htc >change_vec_commute // >nth_change_vec //
585 >change_vec_commute [|@sym_not_eq //] >nth_change_vec //
586 cases (lists_length_split ? ls ls0) #lsa * #lsb * * #Hlen #Hlsalsb
588 [ #Hte #_ #_ <(reverse_reverse … ls) in Hte; <(reverse_reverse … lsa)
589 cut (|reverse ? lsa| = |reverse ? ls|) [ // ] #Hlen'
590 @(list_cases2 … Hlen')
591 [ #H1 #H2 >H1 >H2 -H1 -H2 normalize in match (reverse ? [ ]); #Hte
592 lapply (Hte … (refl ??) … (refl ??) (refl ??)) -Hte
593 >change_vec_commute // >change_vec_change_vec
594 >change_vec_commute [|@sym_not_eq //] >change_vec_change_vec #Hte
595 >Hte * * #_ >nth_change_vec // >reverse_reverse
596 #H lapply (H … (refl ??)) -H #Htb1 #Htb2
597 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)
598 [@daemon] -Htb1 -Htb2 #Htb >Htb whd >nth_change_vec //
599 >nth_change_vec_neq [|@sym_not_eq //] >nth_change_vec //
600 >right_mk_tape normalize in match (left ??);
601 >Hmidta_src >Hmidta_dst >length_tail >Hrs0 >length_append
602 normalize in ⊢ (?(?%)(?%?)); >commutative_plus //
603 | #hda #hdb #tla #tlb #H1 #H2 >H1 >H2
604 >reverse_cons >reverse_cons #Hte
605 lapply (Hte ci hdb (reverse ? xs@s0::reverse ? tlb) rs'' ?
606 lsb cj hda (reverse ? xs@s0::reverse ? tla) rs0' ??)
607 [ /2 by cons_injective_l, nil/
608 | >length_append >length_append @eq_f @(eq_f ?? S)
609 >H1 in Hlen'; >H2 whd in ⊢ (??%%→?); #Hlen'
610 >length_reverse >length_reverse destruct (Hlen') //
611 | /2 by refl, trans_eq/ ] -Hte
612 #Hte * * #_ >Hte >nth_change_vec // #Htb1 #Htb2
613 cut (tb = change_vec ?? (change_vec (tape sig) (S n) ta
614 (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)
615 (midtape ? [ ] hdb (reverse sig (reverse sig xs@s0::reverse sig tlb)@ci::rs'')) src)
616 [@daemon] -Htb1 -Htb2 #Htb >Htb whd
617 >nth_change_vec // >nth_change_vec_neq // >nth_change_vec //
618 >right_mk_tape >Hmidta_src >Hmidta_dst
619 whd in match (left ??); whd in match (left ??); whd in match (right ??);
620 >length_tail >Hrs0 >length_append >length_append >length_reverse
621 >length_append >commutative_plus in match (|reverse ??| + ?);
622 whd in match (|?::?|); >length_reverse >length_reverse
623 <(length_reverse ? ls) <Hlen' >H1 normalize // ]
624 | #_ #Hte #_ <(reverse_reverse … ls0) in Hte; <(reverse_reverse … lsa)
625 cut (|reverse ? lsa| = |reverse ? ls0|) [ // ] #Hlen'
626 @(list_cases2 … Hlen')
627 [ #H1 #H2 >H1 >H2 normalize in match (reverse ? [ ]); #Hte
628 lapply (Hte … (refl ??) … (refl ??) (refl ??)) -Hte
629 >change_vec_change_vec >change_vec_commute [|@sym_not_eq //]
630 >change_vec_change_vec #Hte
631 >Hte * * #_ >nth_change_vec // >reverse_reverse
632 #H lapply (H … (refl ??)) -H #Htb1 #Htb2
633 (* 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) *)
634 cut (tb = change_vec ?? (change_vec (tape sig) (S n) ta (mk_tape ? [s0] (option_hd ? (xs@cj::rs0')) (tail ? (xs@cj::rs0'))) dst)
635 (midtape ? lsb s0 (xs@ci::rs'')) src)
636 [@daemon] -Htb1 -Htb2 #Htb >Htb whd >nth_change_vec //
637 >nth_change_vec_neq // >nth_change_vec //
638 >right_mk_tape normalize in match (left ??);
639 >Hmidta_src >Hmidta_dst >length_tail >Hrs0 >length_append
640 >commutative_plus in match (pred ?); normalize
641 >length_append >(?:|lsa| = O)
642 [ normalize <plus_n_Sm <plus_n_Sm // | <(length_reverse ? lsa) >H1 % ]
643 | #hda #hdb #tla #tlb #H1 #H2 >H1 >H2
644 >reverse_cons >reverse_cons #Hte
645 lapply (Hte cj hdb (reverse ? xs@s0::reverse ? tlb) rs0' ?
646 lsb ci hda (reverse ? xs@s0::reverse ? tla) rs'' ??)
647 [ /2 by cons_injective_l, nil/
648 | >length_append >length_append @eq_f @(eq_f ?? S)
649 >H1 in Hlen'; >H2 whd in ⊢ (??%%→?); #Hlen'
650 >length_reverse >length_reverse destruct (Hlen') //
651 | /2 by refl, trans_eq/ ] -Hte
652 #Hte * * #_ >Hte >nth_change_vec_neq // >nth_change_vec // #Htb1 #Htb2
653 cut (tb = change_vec ?? (change_vec (tape sig) (S n) ta
654 (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)
655 (midtape ? lsb hda (reverse sig (reverse sig xs@s0::reverse sig tla)@ci::rs'')) src)
656 [@daemon] -Htb1 -Htb2 #Htb >Htb whd
657 >nth_change_vec // >nth_change_vec_neq // >nth_change_vec //
658 >right_mk_tape >Hmidta_src >Hmidta_dst
659 whd in match (left ??); whd in match (left ??); whd in match (right ??);
660 >length_tail >Hrs0 >length_append >length_append >length_reverse
661 >length_append >commutative_plus in match (|reverse ??| + ?);
662 whd in match (|?::?|); >length_reverse >length_reverse >Hlen
663 <(length_reverse ? ls0) >H2 whd in match (|?::?|);
664 >length_append normalize //
669 (* lapply (\Pf Hss0) -Hss0 #Hss0 #Htc cut (tc = ta)
670 [@Htc % % @(not_to_not ??? Hss0) #H destruct (H) %]
671 -Htc #Htc destruct (Htc) #_ * #td * whd in ⊢ (%→?); * #_
672 #Htd destruct (Htd) * #te * * * # #_ >Hmidta_src >Hmidta_dst #Hte
673 lapply (Hte … (refl ??) … (refl ??)) * * #_ #Htb1 #Htb2
674 #s1 #rs1 >Hmidta_src #H destruct (H)
675 lapply (Hte … Hmidta_src … Hmidta_dst) -Hte #Hte destruct (Hte) %
676 [ @(eq_vec … (niltape ?)) #i #Hi
677 cases (true_or_false ((dst : DeqNat) == i)) #Hdsti
678 [ <(\P Hdsti) >(Htb1 … Hmidta_dst) >nth_change_vec // >Hmidta_dst
679 cases rs0 [|#r2 #rs2] %
680 | <Htb2 [|@(\Pf Hdsti)] >nth_change_vec_neq [| @(\Pf Hdsti)] % ]
681 | >Hs0 %{s0} % // #H destruct (H) @False_ind cases (Hss0) /2/ ] *)
685 | #ta #tb #tc * #Hcomp1 #Hcomp2 * #td * * #Htest #Htd destruct (Htd)
686 whd in ⊢ (%→?); #Htb destruct (Htb) #ls #x #xs #Hta_src
687 lapply (refl ? (current ? (nth dst ? ta (niltape ?))))
688 cases (current ? (nth dst ? ta (niltape ?))) in ⊢ (???%→?);
689 [ #Hcurta_dst % % % // @Hcomp1 %2 //
690 | #x0 #Hcurta_dst cases (current_to_midtape … Hcurta_dst) -Hcurta_dst
691 #ls0 * #rs0 #Hta_dst cases (true_or_false (x == x0)) #Hxx0
692 [ lapply (\P Hxx0) -Hxx0 #Hxx0 destruct (Hxx0)
693 | >(?:tc=ta) in Htest;
694 [|@Hcomp1 % % >Hta_src >Hta_dst @(not_to_not ??? (\Pf Hxx0)) normalize
695 #Hxx0' destruct (Hxx0') % ]
697 >nth_current_chars >Hta_src >nth_current_chars >Hta_dst
698 whd in ⊢ (??%?→?); #Hfalse destruct (Hfalse) ] -Hcomp1
699 cases (Hcomp2 … Hta_src Hta_dst) [ *
700 [ * #rs' * #Hxs #Hcurtc % %2 %{ls0} %{rs0} %{rs'} %
702 | * #rs0' * #Hxs #Htc %2 >Htc %{ls0} %{rs0'} % // ]
703 | * #xs0 * #ci * #cj * #rs' * #rs0' * * *
704 #Hci #Hxs #Hrs0 #Htc @False_ind
706 >(?:nth src ? (current_chars ?? tc) (None ?) = Some ? ci) in Htest;
707 [|>nth_current_chars >Htc >nth_change_vec_neq [|@(not_to_not … Hneq) //]
709 >(?:nth dst ? (current_chars ?? tc) (None ?) = Some ? cj)
710 [|>nth_current_chars >Htc >nth_change_vec //]
711 normalize #H destruct (H) ] ] ]
715 definition Pre_match_m ≝
716 λsrc,sig,n.λt: Vector (tape sig) (S n).
718 nth src (tape sig) t (niltape sig) = midtape ? [] x xs.
720 lemma terminate_match_m :
722 src ≠ dst → src < S n → dst < S n →
723 Pre_match_m src sig n t →
724 match_m src dst sig n ↓ t.
725 #src #dst #sig #n #t #Hneq #Hsrc #Hdst * #start * #xs
727 @(terminate_while … (sem_match_step src dst sig n Hneq Hsrc Hdst)) //
728 <(change_vec_same … t dst (niltape ?))
729 lapply (refl ? (nth dst (tape sig) t (niltape ?)))
730 cases (nth dst (tape sig) t (niltape ?)) in ⊢ (???%→?);
731 [ #Htape_dst % #t1 whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
732 >Hmid_src #HR cases (HR ?? (refl ??)) -HR
733 >nth_change_vec // >Htape_dst #_ * #s0 * normalize in ⊢ (%→?); #H destruct (H)
734 | #x0 #xs0 #Htape_dst % #t1 whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
735 >Hmid_src #HR cases (HR ?? (refl ??)) -HR
736 >nth_change_vec // >Htape_dst #_ normalize in ⊢ (%→?);
737 * #s0 * #H destruct (H)
738 | #x0 #xs0 #Htape_dst % #t1 whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
739 >Hmid_src #HR cases (HR ?? (refl ??)) -HR
740 >nth_change_vec // >Htape_dst #_ normalize in ⊢ (%→?);
741 * #s0 * #H destruct (H)
742 | #ls #s #rs lapply s -s lapply ls -ls lapply Hmid_src lapply t -t elim rs
743 [#t #Hmid_src #ls #s #Hmid_dst % #t1 whd in ⊢ (%→?); >nth_change_vec_neq [|@sym_not_eq //]
744 >Hmid_src >nth_change_vec // >Hmid_dst #HR cases (HR ?? (refl ??)) -HR
745 >change_vec_change_vec #Ht1 #_ % #t2 whd in ⊢ (%→?);
746 >Ht1 >nth_change_vec_neq [|@sym_not_eq //] >Hmid_src #HR
747 cases (HR ?? (refl ??)) -HR #_
748 >nth_change_vec // * #s1 * normalize in ⊢ (%→?); #H destruct (H)
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 >change_vec_change_vec
752 >nth_change_vec // >Hmid_dst whd in match (tape_move_mono ???); #Ht1
753 * #s0 * whd in ⊢ (??%?→?); #H destruct (H) #_ >Ht1
754 lapply (IH t1 ? (s0::ls) r0 ?)
755 [ >Ht1 >nth_change_vec //
756 | >Ht1 >nth_change_vec_neq [|@sym_not_eq //] @Hmid_src
757 | >Ht1 >nth_change_vec // ]