2 ||M|| This file is part of HELM, an Hypertextual, Electronic
3 ||A|| Library of Mathematics, developed at the Computer Science
4 ||T|| Department of the University of Bologna, Italy.
8 \ / This file is distributed under the terms of the
9 \ / GNU General Public License Version 2
10 V_____________________________________________________________*)
12 include "turing/turing.ma".
13 include "turing/inject.ma".
14 include "turing/while_multi.ma".
16 definition parmove_states ≝ initN 3.
18 definition parmove0 : parmove_states ≝ mk_Sig ?? 0 (leb_true_to_le 1 3 (refl …)).
19 definition parmove1 : parmove_states ≝ mk_Sig ?? 1 (leb_true_to_le 2 3 (refl …)).
20 definition parmove2 : parmove_states ≝ mk_Sig ?? 2 (leb_true_to_le 3 3 (refl …)).
24 src: a b c ... z # ---→ a b c ... z #
27 dst: _ _ _ ... _ d ---→ a b c ... z d
30 0) (x ≠ sep,_) → (x,x)(R,R) → 1
37 definition trans_parmove_step ≝
38 λsrc,dst,sig,n,D,is_sep.
39 λp:parmove_states × (Vector (option sig) (S n)).
42 [ O ⇒ match nth src ? a (None ?) with
43 [ None ⇒ 〈parmove2,null_action ? n〉
45 if is_sep a0 then 〈parmove2,null_action ? n〉
46 else match nth dst ? a (None ?) with
47 [ None ⇒ 〈parmove2,null_action ? n〉
48 | Some a1 ⇒ 〈parmove1,change_vec ? (S n)
50 (null_action ? n) (Some ? 〈a0,D〉) src)
51 (Some ? 〈a1,D〉) dst〉 ] ]
53 [ O ⇒ (* 1 *) 〈parmove1,null_action ? n〉
54 | S _ ⇒ (* 2 *) 〈parmove2,null_action ? n〉 ] ].
56 definition parmove_step ≝
57 λsrc,dst,sig,n,D,is_sep.
58 mk_mTM sig n parmove_states (trans_parmove_step src dst sig n D is_sep)
59 parmove0 (λq.q == parmove1 ∨ q == parmove2).
61 definition R_parmove_step_true ≝
62 λsrc,dst,sig,n,D,is_sep.λint,outt: Vector (tape sig) (S n).
64 current ? (nth src ? int (niltape ?)) = Some ? x1 ∧
65 current ? (nth dst ? int (niltape ?)) = Some ? x2 ∧
69 (tape_move ? (nth src ? int (niltape ?)) (Some ? 〈x1,D〉)) src)
70 (tape_move ? (nth dst ? int (niltape ?)) (Some ? 〈x2,D〉)) dst.
72 definition R_parmove_step_false ≝
73 λsrc,dst:nat.λsig,n,is_sep.λint,outt: Vector (tape sig) (S n).
75 current ? (nth src ? int (niltape ?)) = Some ? x1 ∧
77 current ? (nth src ? int (niltape ?)) = None ? ∨
78 current ? (nth dst ? int (niltape ?)) = None ?) ∧
81 lemma parmove_q0_q2_null_src :
82 ∀src,dst,sig,n,D,is_sep,v.src < S n → dst < S n →
83 nth src ? (current_chars ?? v) (None ?) = None ? →
84 step sig n (parmove_step src dst sig n D is_sep)
85 (mk_mconfig ??? parmove0 v) =
86 mk_mconfig ??? parmove2 v.
87 #src #dst #sig #n #D #is_sep #v #Hsrc #Hdst #Hcurrent
88 whd in ⊢ (??%?); >(eq_pair_fst_snd … (trans ????)) whd in ⊢ (??%?);
90 [ whd in ⊢ (??(???%)?); >Hcurrent %
91 | whd in ⊢ (??(???????(???%))?); >Hcurrent @tape_move_null_action ]
94 lemma parmove_q0_q2_sep :
95 ∀src,dst,sig,n,D,is_sep,v,s.src < S n → dst < S n →
96 nth src ? (current_chars ?? v) (None ?) = Some ? s → is_sep s = true →
97 step sig n (parmove_step src dst sig n D is_sep)
98 (mk_mconfig ??? parmove0 v) =
99 mk_mconfig ??? parmove2 v.
100 #src #dst #sig #n #D #is_sep #v #s #Hsrc #Hdst #Hcurrent #Hsep
101 whd in ⊢ (??%?); >(eq_pair_fst_snd … (trans ????)) whd in ⊢ (??%?);
103 [ whd in ⊢ (??(???%)?); >Hcurrent whd in ⊢ (??(???%)?); >Hsep %
104 | whd in ⊢ (??(???????(???%))?); >Hcurrent
105 whd in ⊢ (??(???????(???%))?); >Hsep @tape_move_null_action ]
108 lemma parmove_q0_q2_null_dst :
109 ∀src,dst,sig,n,D,is_sep,v,s.src < S n → dst < S n →
110 nth src ? (current_chars ?? v) (None ?) = Some ? s → is_sep s = false →
111 nth dst ? (current_chars ?? v) (None ?) = None ? →
112 step sig n (parmove_step src dst sig n D is_sep)
113 (mk_mconfig ??? parmove0 v) =
114 mk_mconfig ??? parmove2 v.
115 #src #dst #sig #n #D #is_sep #v #s #Hsrc #Hdst #Hcursrc #Hsep #Hcurdst
116 whd in ⊢ (??%?); >(eq_pair_fst_snd … (trans ????)) whd in ⊢ (??%?);
118 [ whd in ⊢ (??(???%)?); >Hcursrc whd in ⊢ (??(???%)?); >Hsep >Hcurdst %
119 | whd in ⊢ (??(???????(???%))?); >Hcursrc
120 whd in ⊢ (??(???????(???%))?); >Hsep >Hcurdst @tape_move_null_action ]
123 lemma parmove_q0_q1 :
124 ∀src,dst,sig,n,D,is_sep,v.src ≠ dst → src < S n → dst < S n →
126 nth src ? (current_chars ?? v) (None ?) = Some ? a1 →
127 nth dst ? (current_chars ?? v) (None ?) = Some ? a2 →
129 step sig n (parmove_step src dst sig n D is_sep)
130 (mk_mconfig ??? parmove0 v) =
131 mk_mconfig ??? parmove1
134 (tape_move ? (nth src ? v (niltape ?)) (Some ? 〈a1,D〉)) src)
135 (tape_move ? (nth dst ? v (niltape ?)) (Some ? 〈a2,D〉)) dst).
136 #src #dst #sig #n #D #is_sep #v #Hneq #Hsrc #Hdst
137 #a1 #a2 #Hcursrc #Hcurdst #Hsep
138 whd in ⊢ (??%?); >(eq_pair_fst_snd … (trans ????)) whd in ⊢ (??%?); @eq_f2
139 [ whd in match (trans ????);
140 >Hcursrc >Hcurdst whd in ⊢ (??(???%)?); >Hsep //
141 | whd in match (trans ????);
142 >Hcursrc >Hcurdst whd in ⊢ (??(???????(???%))?); >Hsep
143 change with (change_vec ?????) in ⊢ (??(???????%)?);
144 <(change_vec_same … v dst (niltape ?)) in ⊢ (??%?);
145 <(change_vec_same … v src (niltape ?)) in ⊢ (??%?);
146 >pmap_change >pmap_change >tape_move_null_action
147 @eq_f2 // @eq_f2 // >nth_change_vec_neq //
151 lemma sem_parmove_step :
152 ∀src,dst,sig,n,D,is_sep.src ≠ dst → src < S n → dst < S n →
153 parmove_step src dst sig n D is_sep ⊨
154 [ parmove1: R_parmove_step_true src dst sig n D is_sep,
155 R_parmove_step_false src dst sig n is_sep ].
156 #src #dst #sig #n #D #is_sep #Hneq #Hsrc #Hdst #int
157 lapply (refl ? (current ? (nth src ? int (niltape ?))))
158 cases (current ? (nth src ? int (niltape ?))) in ⊢ (???%→?);
161 [ whd in ⊢ (??%?); >parmove_q0_q2_null_src /2/
162 <(nth_vec_map ?? (current …) src ? int (niltape ?)) //
163 | normalize in ⊢ (%→?); #H destruct (H) ]
164 | #_ % // % %2 // ] ]
165 | #a #Ha cases (true_or_false (is_sep a)) #Hsep
168 [ whd in ⊢ (??%?); >(parmove_q0_q2_sep … Hsep) /2/
169 <(nth_vec_map ?? (current …) src ? int (niltape ?)) //
170 | normalize in ⊢ (%→?); #H destruct (H) ]
171 | #_ % // % % %{a} % // ] ]
172 | lapply (refl ? (current ? (nth dst ? int (niltape ?))))
173 cases (current ? (nth dst ? int (niltape ?))) in ⊢ (???%→?);
176 [ whd in ⊢ (??%?); >(parmove_q0_q2_null_dst … Hsep) /2/
177 [ <(nth_vec_map ?? (current …) dst ? int (niltape ?)) //
178 | <(nth_vec_map ?? (current …) src ? int (niltape ?)) // ]
179 | normalize in ⊢ (%→?); #H destruct (H) ]
183 [whd in ⊢ (??%?); >(parmove_q0_q1 … Hneq Hsrc Hdst ? b ?? Hsep) //
184 [ <(nth_vec_map ?? (current …) dst ? int (niltape ?)) //
185 | <(nth_vec_map ?? (current …) src ? int (niltape ?)) // ]
186 | #_ %{a} %{b} % // % // % // ]
187 | * #H @False_ind @H % ]
191 definition parmove ≝ λsrc,dst,sig,n,D,is_sep.
192 whileTM … (parmove_step src dst sig n D is_sep) parmove1.
194 definition R_parmoveL ≝
195 λsrc,dst,sig,n,is_sep.λint,outt: Vector (tape sig) (S n).
197 nth src ? int (niltape ?) = midtape sig (xs@sep::ls) x rs →
198 (∀c.memb ? c (x::xs) = true → is_sep c = false) → is_sep sep = true →
199 ∀ls0,x0,target,c,rs0.|xs| = |target| →
200 nth dst ? int (niltape ?) = midtape sig (target@c::ls0) x0 rs0 →
202 (change_vec ?? int (midtape sig ls sep (reverse ? xs@x::rs)) src)
203 (midtape sig ls0 c (reverse ? target@x0::rs0)) dst) ∧
204 (∀s.current ? (nth src ? int (niltape ?)) = Some ? s → is_sep s = true →
207 lemma wsem_parmoveL : ∀src,dst,sig,n,is_sep.src ≠ dst → src < S n → dst < S n →
208 parmove src dst sig n L is_sep ⊫ R_parmoveL src dst sig n is_sep.
209 #src #dst #sig #n #is_sep #Hneq #Hsrc #Hdst #ta #k #outc #Hloop
210 lapply (sem_while … (sem_parmove_step src dst sig n L is_sep Hneq Hsrc Hdst) … Hloop) //
211 -Hloop * #tb * #Hstar @(star_ind_l ??????? Hstar) -Hstar
212 [ #tc whd in ⊢ (%→?); * * [ *
213 [ * #x * #Hx #Hsep #Houtc %
214 [ #ls #x0 #xs #rs #sep #Hsrctc #Hnosep >Hsrctc in Hx; normalize in ⊢ (%→?);
215 #Hx0 destruct (Hx0) lapply (Hnosep ? (memb_hd …)) >Hsep
216 #Hfalse destruct (Hfalse)
217 | #s #Hs #Hseps @Houtc ]
219 [ #ls #x0 #xs #rs #sep #Hsrctc >Hsrctc in Hcur; normalize in ⊢ (%→?);
220 #Hcur destruct (Hcur)
221 | >Hcur #s #Hs destruct (Hs) ] ]
223 [ #ls #x0 #xs #rs #sep #Hsrctc #Hnosep #Hsep #ls0 #x1 #target #c #rs0 #Hlen
224 #Hdsttc >Hdsttc in Hcur; normalize in ⊢ (%→?); #Hcur destruct (Hcur)
225 | #s #Hs #Hseps @Houtc ]
227 | #tc #td #te * #c0 * #c1 * * * #Hc0 #Hc1 #Hc0nosep #Hd #Hstar #IH #He
228 lapply (IH He) -IH * #IH1 #IH2 %
229 [ #ls #x #xs #rs #sep #Hsrc_tc #Hnosep #Hsep #ls0 #x0 #target
230 #c #rs0 #Hlen #Hdst_tc
231 >Hsrc_tc in Hc0; normalize in ⊢ (%→?); #Hc0 destruct (Hc0)
232 (* <(change_vec_same … tc src (niltape ?)) in Hd:(???(???(???%??)??));
233 <(change_vec_same … tc dst (niltape ?)) in ⊢(???(???(???%??)??)→?); *)
234 >Hdst_tc in Hd; >Hsrc_tc
235 (* >change_vec_change_vec >change_vec_change_vec
236 >(change_vec_commute ?? tc ?? dst src) [|@(sym_not_eq … Hneq)]
237 >change_vec_change_vec *) @(list_cases2 … Hlen)
238 [ #Hxsnil #Htargetnil >Hxsnil >Htargetnil #Hd >(IH2 … Hsep)
239 [ >Hd -Hd @(eq_vec … (niltape ?))
240 #i #Hi cases (decidable_eq_nat i src) #Hisrc
241 [ >Hisrc >(nth_change_vec_neq … src dst) [|@(sym_not_eq … Hneq)]
243 >(nth_change_vec_neq … src dst) [|@(sym_not_eq … Hneq)]
245 | cases (decidable_eq_nat i dst) #Hidst
246 [ >Hidst >nth_change_vec // >nth_change_vec //
247 >Hdst_tc in Hc1; >Htargetnil
248 normalize in ⊢ (%→?); #Hc1 destruct (Hc1) %
249 | >nth_change_vec_neq [|@(sym_not_eq … Hidst)]
250 >nth_change_vec_neq [|@(sym_not_eq … Hisrc)]
251 >nth_change_vec_neq [|@(sym_not_eq … Hidst)]
252 >nth_change_vec_neq [|@(sym_not_eq … Hisrc)] % ]
254 | >Hd >nth_change_vec_neq [|@(sym_not_eq … Hneq)]
256 | #hd1 #hd2 #tl1 #tl2 #Hxs #Htarget >Hxs >Htarget #Hd
257 >(IH1 ls hd1 tl1 (c0::rs) sep ?? Hsep ls0 hd2 tl2 c (x0::rs0))
258 [ >Hd >(change_vec_commute … ?? tc ?? src dst) //
259 >change_vec_change_vec
260 >(change_vec_commute … ?? tc ?? dst src) [|@sym_not_eq //]
261 >change_vec_change_vec
262 >reverse_cons >associative_append
263 >reverse_cons >associative_append %
264 | >Hd >nth_change_vec // >Hdst_tc >Htarget >Hdst_tc in Hc1;
265 normalize in ⊢ (%→?); #H destruct (H) //
266 | >Hxs in Hlen; >Htarget normalize #Hlen destruct (Hlen) //
267 | <Hxs #c1 #Hc1 @Hnosep @memb_cons //
268 | >Hd >nth_change_vec_neq [|@sym_not_eq //]
271 | #c #Hc #Hsepc >Hc in Hc0; #Hcc0 destruct (Hcc0) >Hc0nosep in Hsepc;
276 lemma terminate_copy : ∀src,dst,sig,n,is_sep,t.
277 src ≠ dst → src < S n → dst < S n →
278 copy src dst sig n is_sep ↓ t.
279 #src #dst #sig #n #is_sep #t #Hneq #Hsrc #Hdst
280 @(terminate_while … (sem_copy_step …)) //
281 <(change_vec_same … t src (niltape ?))
282 cases (nth src (tape sig) t (niltape ?))
283 [ % #t1 * #x * * >nth_change_vec // normalize in ⊢ (%→?); #Hx destruct
284 |2,3: #a0 #al0 % #t1 * #x * * >nth_change_vec // normalize in ⊢ (%→?); #Hx destruct
285 | #ls #c #rs lapply c -c lapply ls -ls lapply t -t elim rs
286 [#t #ls #c % #t1 * #x * * >nth_change_vec // normalize in ⊢ (%→?);
287 #H1 destruct (H1) #Hxsep >change_vec_change_vec #Ht1 %
288 #t2 * #x0 * * >Ht1 >nth_change_vec_neq [|@sym_not_eq //]
289 >nth_change_vec // normalize in ⊢ (%→?); #H destruct (H)
290 |#r0 #rs0 #IH #t #ls #c % #t1 * #x * * >nth_change_vec //
291 normalize in ⊢ (%→?); #H destruct (H) #Hxsep
292 >change_vec_change_vec >change_vec_commute // #Ht1 >Ht1 @IH
297 lemma sem_copy : ∀src,dst,sig,n,is_sep.
298 src ≠ dst → src < S n → dst < S n →
299 copy src dst sig n is_sep ⊨ R_copy src dst sig n is_sep.
300 #src #dst #sig #n #is_sep #Hneq #Hsrc #Hdst @WRealize_to_Realize /2/