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_____________________________________________________________*)
17 include "turing/universal/marks.ma".
19 definition STape ≝ FinProd … FSUnialpha FinBool.
21 definition only_bits ≝ λl.
22 ∀c.memb STape c l = true → is_bit (\fst c) = true.
24 definition no_grids ≝ λl.
25 ∀c.memb STape c l = true → is_grid (\fst c) = false.
27 definition no_bars ≝ λl.
28 ∀c.memb STape c l = true → is_bar (\fst c) = false.
30 definition no_marks ≝ λl.
31 ∀c.memb STape c l = true → is_marked ? c = false.
33 definition tuple_TM : nat → list STape → Prop ≝
34 λn,t.∃qin,qout,mv,b1,b2.
35 only_bits qin ∧ only_bits qout ∧ only_bits mv ∧
36 |qin| = n ∧ |qout| = n (* ∧ |mv| = ? *) ∧
37 t = qin@〈comma,b1〉::qout@〈comma,b2〉::mv.
39 inductive table_TM : nat → list STape → Prop ≝
40 | ttm_nil : ∀n.table_TM n []
41 | ttm_cons : ∀n,t1,T,b.tuple_TM n t1 → table_TM n T → table_TM n (t1@〈bar,b〉::T).
44 l0 x* a l1 x0* a0 l2 ------> l0 x a* l1 x0 a0* l2
47 if current (* x *) = #
52 if current (* x0 *) = 0
53 then advance_mark ----
57 else x = 1 (* analogo *)
63 MARK NEXT TUPLE machine
64 (partially axiomatized)
66 marks the first character after the first bar (rightwards)
69 definition bar_or_grid ≝ λc:STape.is_bar (\fst c) ∨ is_grid (\fst c).
71 definition mark_next_tuple ≝
72 seq ? (adv_to_mark_r ? bar_or_grid)
73 (ifTM ? (test_char ? (λc:STape.is_bar (\fst c)))
74 (move_right_and_mark ?) (nop ?) 1).
76 definition R_mark_next_tuple ≝
79 (* c non può essere un separatore ... speriamo *)
80 t1 = midtape STape ls c (rs1@〈grid,false〉::rs2) →
81 no_marks rs1 → no_grids rs1 → bar_or_grid c = false →
82 (∃rs3,rs4,d,b.rs1 = rs3 @ 〈bar,false〉 :: rs4 ∧
84 Some ? 〈d,b〉 = option_hd ? (rs4@〈grid,false〉::rs2) ∧
85 t2 = midtape STape (〈bar,false〉::reverse ? rs3@c::ls) 〈d,true〉 (tail ? (rs4@〈grid,false〉::rs2)))
87 (no_bars rs1 ∧ t2 = midtape ? (reverse ? rs1@c::ls) 〈grid,false〉 rs2).
91 (∀x.memb A x l = true → f x = false) ∨
92 (∃l1,c,l2.f c = true ∧ l = l1@c::l2 ∧ ∀x.memb ? x l1 = true → f x = false).
94 [ % #x normalize #Hfalse *)
96 theorem sem_mark_next_tuple :
97 Realize ? mark_next_tuple R_mark_next_tuple.
99 lapply (sem_seq ? (adv_to_mark_r ? bar_or_grid)
100 (ifTM ? (test_char ? (λc:STape.is_bar (\fst c))) (move_right_and_mark ?) (nop ?) 1) ????)
101 [@sem_if [5: // |6: @sem_move_right_and_mark |7: // |*:skip]
103 |||#Hif cases (Hif intape) -Hif
104 #j * #outc * #Hloop * #ta * #Hleft #Hright
105 @(ex_intro ?? j) @ex_intro [|% [@Hloop] ]
107 #ls #c #rs1 #rs2 #Hrs #Hrs1 #Hrs1' #Hc
109 [ * #Hfalse >Hfalse in Hc; #Htf destruct (Htf)
110 | * #_ #Hta cases (tech_split STape (λc.is_bar (\fst c)) rs1)
111 [ #H1 lapply (Hta rs1 〈grid,false〉 rs2 (refl ??) ? ?)
112 [ * #x #b #Hx whd in ⊢ (??%?); >(Hrs1' … Hx) >(H1 … Hx) %
114 | -Hta #Hta cases Hright
115 [ * #tb * whd in ⊢ (%→?); #Hcurrent
116 @False_ind cases (Hcurrent 〈grid,false〉 ?)
117 [ normalize #Hfalse destruct (Hfalse)
119 | * #tb * whd in ⊢ (%→?); #Hcurrent
120 cases (Hcurrent 〈grid,false〉 ?)
121 [ #_ #Htb whd in ⊢ (%→?); #Houtc
124 | >Houtc >Htb >Hta % ]
128 | * #rs3 * #c0 * #rs4 * * #Hc0 #Hsplit #Hrs3
129 % @(ex_intro ?? rs3) @(ex_intro ?? rs4)
130 lapply (Hta rs3 c0 (rs4@〈grid,false〉::rs2) ???)
131 [ #x #Hrs3' whd in ⊢ (??%?); >Hsplit in Hrs1;>Hsplit in Hrs3;
132 #Hrs3 #Hrs1 >(Hrs1 …) [| @memb_append_l1 @Hrs3'|]
133 >(Hrs3 … Hrs3') @Hrs1' >Hsplit @memb_append_l1 //
134 | whd in ⊢ (??%?); >Hc0 %
135 | >Hsplit >associative_append % ] -Hta #Hta
137 [ * #tb * whd in ⊢ (%→?); #Hta'
140 [ #_ #Htb' >Htb' in Htb; #Htb
141 generalize in match Hsplit; -Hsplit
143 [ #Hta #Hsplit >(Htb … Hta)
144 >(?:c0 = 〈bar,false〉)
145 [ @(ex_intro ?? grid) @(ex_intro ?? false)
147 [(* Hsplit *) @daemon |(*Hrs3*) @daemon ] | % ] | % ]
148 | (* Hc0 *) @daemon ]
149 | #r5 #rs5 >(eq_pair_fst_snd … r5)
150 #Hta #Hsplit >(Htb … Hta)
151 >(?:c0 = 〈bar,false〉)
152 [ @(ex_intro ?? (\fst r5)) @(ex_intro ?? (\snd r5))
153 % [ % [ % [ (* Hc0, Hsplit *) @daemon | (*Hrs3*) @daemon ] | % ]
154 | % ] | (* Hc0 *) @daemon ] ] | >Hta % ]
155 | * #tb * whd in ⊢ (%→?); #Hta'
158 [ #Hfalse @False_ind >Hfalse in Hc0;
164 definition init_current ≝
165 seq ? (adv_to_mark_l ? (is_marked ?))
166 (seq ? (clear_mark ?)
167 (seq ? (adv_to_mark_l ? (λc:STape.is_grid (\fst c)))
168 (seq ? (move_r ?) (mark ?)))).
170 definition R_init_current ≝ λt1,t2.
171 ∀l1,c,l2,b,l3,c1,rs,c0,b0. no_marks l1 → no_grids l2 → is_grid c = false →
172 Some ? 〈c0,b0〉 = option_hd ? (reverse ? (〈c,true〉::l2)) →
173 t1 = midtape STape (l1@〈c,true〉::l2@〈grid,b〉::l3) 〈c1,false〉 rs →
174 t2 = midtape STape (〈grid,b〉::l3) 〈c0,true〉
175 ((tail ? (reverse ? (l1@〈c,false〉::l2))@〈c1,false〉::rs)).
177 lemma sem_init_current : Realize ? init_current R_init_current.
179 cases (sem_seq ????? (sem_adv_to_mark_l ? (is_marked ?))
180 (sem_seq ????? (sem_clear_mark ?)
181 (sem_seq ????? (sem_adv_to_mark_l ? (λc:STape.is_grid (\fst c)))
182 (sem_seq ????? (sem_move_r ?) (sem_mark ?)))) intape)
183 #k * #outc * #Hloop #HR
184 @(ex_intro ?? k) @(ex_intro ?? outc) % [@Hloop]
185 cases HR -HR #ta * whd in ⊢ (%→?); #Hta
186 * #tb * whd in ⊢ (%→?); #Htb
187 * #tc * whd in ⊢ (%→?); #Htc
188 * #td * whd in ⊢ (%→%→?); #Htd #Houtc
189 #l1 #c #l2 #b #l3 #c1 #rs #c0 #b0 #Hl1 #Hl2 #Hc #Hc0 #Hintape
190 cases (Hta … Hintape) [ * #Hfalse normalize in Hfalse; destruct (Hfalse) ]
191 -Hta * #_ #Hta lapply (Hta l1 〈c,true〉 ? (refl ??) ??) [@Hl1|%]
192 -Hta #Hta lapply (Htb … Hta) -Htb #Htb cases (Htc … Htb) [ >Hc -Hc * #Hc destruct (Hc) ]
193 -Htc * #_ #Htc lapply (Htc … (refl ??) (refl ??) ?) [@Hl2]
194 -Htc #Htc lapply (Htd … Htc) -Htd
195 >reverse_append >reverse_cons
196 >reverse_cons in Hc0; cases (reverse … l2)
197 [ normalize in ⊢ (%→?); #Hc0 destruct (Hc0)
198 #Htd >(Houtc … Htd) %
199 | * #c2 #b2 #tl2 normalize in ⊢ (%→?);
200 #Hc0 #Htd >(Houtc … Htd)
201 whd in ⊢ (???%); destruct (Hc0)
202 >associative_append >associative_append %
206 definition match_tuple_step ≝
207 ifTM ? (test_char ? (λc:STape.¬ is_grid (\fst c)))
210 (ifTM ? (test_char ? (λc:STape.is_grid (\fst c)))
212 (seq ? mark_next_tuple
213 (ifTM ? (test_char ? (λc:STape.is_grid (\fst c)))
214 (mark ?) (seq ? (move_l ?) init_current) tc_true)) tc_true)))
217 definition R_match_tuple_step_true ≝ λt1,t2.
218 ∀ls,c,l1,l2,c1,l3,l4,rs,n.
219 is_bit c = true → only_bits l1 → no_grids l2 → is_bit c1 = true →
220 only_bits l3 → n = |l2| → |l2| = |l3| →
221 table_TM (S n) (〈c1,true〉::l3@〈comma,false〉::l4) →
222 t1 = midtape STape (〈grid,false〉::ls) 〈c,true〉
223 (l1@〈grid,false〉::l2@〈bar,false〉::〈c1,true〉::l3@〈comma,false〉::l4@〈grid,false〉::rs) →
225 (〈c,true〉::l2 = 〈c1,true〉::l3 ∧
226 t2 = midtape ? (reverse ? l2@〈c,false〉::〈grid,false〉::ls) 〈grid,false〉
227 (l2@〈bar,false〉::〈c1,false〉::l3@〈comma,true〉::l4@〈grid,false〉::rs))
229 (* non facciamo match e marchiamo la prossima tupla *)
230 (〈c,true〉::l2 ≠ 〈c1,true〉::l3 ∧
231 ∃c2,l5,l6,l7.l4 = l5@〈bar,false〉::〈c2,false〉::l6@〈comma,false〉::l7 ∧
232 (* condizioni su l5 l6 l7 *)
233 t2 = midtape STape (〈grid,false〉::ls) 〈c,true〉
234 (l1@〈grid,false〉::l2@〈bar,false〉::〈c1,true〉::l3@〈comma,false〉::
235 l5@〈bar,false〉::〈c2,true〉::l6@〈comma,false〉::l7))
237 (* non facciamo match e non c'è una prossima tupla:
238 non specifichiamo condizioni sul nastro di output, perché
239 non eseguiremo altre operazioni, quindi il suo formato non ci interessa *)
240 (〈c,true〉::l2 ≠ 〈c1,true〉::l3 ∧ no_bars l4 ∧ current ? t2 = Some ? 〈grid,true〉).
242 definition R_match_tuple_step_false ≝ λt1,t2.
243 ∀ls,c,rs.t1 = midtape STape ls c rs → is_grid (\fst c) = true ∧ t2 = t1.