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 "ground_2/ynat/ynat_max.ma".
16 include "basic_2/notation/relations/psubst_6.ma".
17 include "basic_2/grammar/genv.ma".
18 include "basic_2/substitution/lsuby.ma".
20 (* CONTEXT-SENSITIVE EXTENDED ORDINARY SUBSTITUTION FOR TERMS ***************)
23 inductive cpy: ynat → ynat → relation4 genv lenv term term ≝
24 | cpy_atom : ∀I,G,L,l,m. cpy l m G L (⓪{I}) (⓪{I})
25 | cpy_subst: ∀I,G,L,K,V,W,i,l,m. l ≤ yinj i → i < l+m →
26 ⬇[i] L ≡ K.ⓑ{I}V → ⬆[0, i+1] V ≡ W → cpy l m G L (#i) W
27 | cpy_bind : ∀a,I,G,L,V1,V2,T1,T2,l,m.
28 cpy l m G L V1 V2 → cpy (⫯l) m G (L.ⓑ{I}V1) T1 T2 →
29 cpy l m G L (ⓑ{a,I}V1.T1) (ⓑ{a,I}V2.T2)
30 | cpy_flat : ∀I,G,L,V1,V2,T1,T2,l,m.
31 cpy l m G L V1 V2 → cpy l m G L T1 T2 →
32 cpy l m G L (ⓕ{I}V1.T1) (ⓕ{I}V2.T2)
35 interpretation "context-sensitive extended ordinary substritution (term)"
36 'PSubst G L T1 l m T2 = (cpy l m G L T1 T2).
38 (* Basic properties *********************************************************)
40 lemma lsuby_cpy_trans: ∀G,l,m. lsub_trans … (cpy l m G) (lsuby l m).
41 #G #l #m #L1 #T1 #T2 #H elim H -G -L1 -T1 -T2 -l -m
43 | #I #G #L1 #K1 #V #W #i #l #m #Hli #Hilm #HLK1 #HVW #L2 #HL12
44 elim (lsuby_drop_trans_be … HL12 … HLK1) -HL12 -HLK1 /2 width=5 by cpy_subst/
45 | /4 width=1 by lsuby_succ, cpy_bind/
46 | /3 width=1 by cpy_flat/
50 lemma cpy_refl: ∀G,T,L,l,m. ⦃G, L⦄ ⊢ T ▶[l, m] T.
51 #G #T elim T -T // * /2 width=1 by cpy_bind, cpy_flat/
54 (* Basic_1: was: subst1_ex *)
55 lemma cpy_full: ∀I,G,K,V,T1,L,l. ⬇[l] L ≡ K.ⓑ{I}V →
56 ∃∃T2,T. ⦃G, L⦄ ⊢ T1 ▶[l, 1] T2 & ⬆[l, 1] T ≡ T2.
57 #I #G #K #V #T1 elim T1 -T1
59 /2 width=4 by lift_sort, lift_gref, ex2_2_intro/
60 elim (lt_or_eq_or_gt i l) #Hil
61 /3 width=4 by lift_lref_ge_minus, lift_lref_lt, ex2_2_intro/
63 elim (lift_total V 0 (i+1)) #W #HVW
64 elim (lift_split … HVW i i)
65 /4 width=5 by cpy_subst, ylt_inj, ex2_2_intro/
66 | * [ #a ] #J #W1 #U1 #IHW1 #IHU1 #L #l #HLK
67 elim (IHW1 … HLK) -IHW1 #W2 #W #HW12 #HW2
68 [ elim (IHU1 (L.ⓑ{J}W1) (l+1)) -IHU1
69 /3 width=9 by cpy_bind, drop_drop, lift_bind, ex2_2_intro/
70 | elim (IHU1 … HLK) -IHU1 -HLK
71 /3 width=8 by cpy_flat, lift_flat, ex2_2_intro/
76 lemma cpy_weak: ∀G,L,T1,T2,l1,m1. ⦃G, L⦄ ⊢ T1 ▶[l1, m1] T2 →
77 ∀l2,m2. l2 ≤ l1 → l1 + m1 ≤ l2 + m2 →
78 ⦃G, L⦄ ⊢ T1 ▶[l2, m2] T2.
79 #G #L #T1 #T2 #l1 #m1 #H elim H -G -L -T1 -T2 -l1 -m1 //
80 [ /3 width=5 by cpy_subst, ylt_yle_trans, yle_trans/
81 | /4 width=3 by cpy_bind, ylt_yle_trans, yle_succ/
82 | /3 width=1 by cpy_flat/
86 lemma cpy_weak_top: ∀G,L,T1,T2,l,m.
87 ⦃G, L⦄ ⊢ T1 ▶[l, m] T2 → ⦃G, L⦄ ⊢ T1 ▶[l, |L| - l] T2.
88 #G #L #T1 #T2 #l #m #H elim H -G -L -T1 -T2 -l -m //
89 [ #I #G #L #K #V #W #i #l #m #Hli #_ #HLK #HVW
90 lapply (drop_fwd_length_lt2 … HLK)
91 /4 width=5 by cpy_subst, ylt_yle_trans, ylt_inj/
92 | #a #I #G #L #V1 #V2 normalize in match (|L.ⓑ{I}V2|); (**) (* |?| does not work *)
93 /2 width=1 by cpy_bind/
94 | /2 width=1 by cpy_flat/
98 lemma cpy_weak_full: ∀G,L,T1,T2,l,m.
99 ⦃G, L⦄ ⊢ T1 ▶[l, m] T2 → ⦃G, L⦄ ⊢ T1 ▶[0, |L|] T2.
100 #G #L #T1 #T2 #l #m #HT12
101 lapply (cpy_weak … HT12 0 (l + m) ? ?) -HT12
102 /2 width=2 by cpy_weak_top/
105 lemma cpy_split_up: ∀G,L,T1,T2,l,m. ⦃G, L⦄ ⊢ T1 ▶[l, m] T2 → ∀i. i ≤ l + m →
106 ∃∃T. ⦃G, L⦄ ⊢ T1 ▶[l, i-l] T & ⦃G, L⦄ ⊢ T ▶[i, l+m-i] T2.
107 #G #L #T1 #T2 #l #m #H elim H -G -L -T1 -T2 -l -m
108 [ /2 width=3 by ex2_intro/
109 | #I #G #L #K #V #W #i #l #m #Hli #Hilm #HLK #HVW #j #Hjlm
110 elim (ylt_split i j) [ -Hilm -Hjlm | -Hli ]
111 /4 width=9 by cpy_subst, ylt_yle_trans, ex2_intro/
112 | #a #I #G #L #V1 #V2 #T1 #T2 #l #m #_ #_ #IHV12 #IHT12 #i #Hilm
113 elim (IHV12 i) -IHV12 // #V
114 elim (IHT12 (i+1)) -IHT12 /2 width=1 by yle_succ/ -Hilm
115 >yplus_SO2 >yplus_succ1 #T #HT1 #HT2
116 lapply (lsuby_cpy_trans … HT2 (L.ⓑ{I}V) ?) -HT2
117 /3 width=5 by lsuby_succ, ex2_intro, cpy_bind/
118 | #I #G #L #V1 #V2 #T1 #T2 #l #m #_ #_ #IHV12 #IHT12 #i #Hilm
119 elim (IHV12 i) -IHV12 // elim (IHT12 i) -IHT12 // -Hilm
120 /3 width=5 by ex2_intro, cpy_flat/
124 lemma cpy_split_down: ∀G,L,T1,T2,l,m. ⦃G, L⦄ ⊢ T1 ▶[l, m] T2 → ∀i. i ≤ l + m →
125 ∃∃T. ⦃G, L⦄ ⊢ T1 ▶[i, l+m-i] T & ⦃G, L⦄ ⊢ T ▶[l, i-l] T2.
126 #G #L #T1 #T2 #l #m #H elim H -G -L -T1 -T2 -l -m
127 [ /2 width=3 by ex2_intro/
128 | #I #G #L #K #V #W #i #l #m #Hli #Hilm #HLK #HVW #j #Hjlm
129 elim (ylt_split i j) [ -Hilm -Hjlm | -Hli ]
130 /4 width=9 by cpy_subst, ylt_yle_trans, ex2_intro/
131 | #a #I #G #L #V1 #V2 #T1 #T2 #l #m #_ #_ #IHV12 #IHT12 #i #Hilm
132 elim (IHV12 i) -IHV12 // #V
133 elim (IHT12 (i+1)) -IHT12 /2 width=1 by yle_succ/ -Hilm
134 >yplus_SO2 >yplus_succ1 #T #HT1 #HT2
135 lapply (lsuby_cpy_trans … HT2 (L.ⓑ{I}V) ?) -HT2
136 /3 width=5 by lsuby_succ, ex2_intro, cpy_bind/
137 | #I #G #L #V1 #V2 #T1 #T2 #l #m #_ #_ #IHV12 #IHT12 #i #Hilm
138 elim (IHV12 i) -IHV12 // elim (IHT12 i) -IHT12 // -Hilm
139 /3 width=5 by ex2_intro, cpy_flat/
143 (* Basic forward lemmas *****************************************************)
145 lemma cpy_fwd_up: ∀G,L,U1,U2,lt,mt. ⦃G, L⦄ ⊢ U1 ▶[lt, mt] U2 →
146 ∀T1,l,m. ⬆[l, m] T1 ≡ U1 →
147 l ≤ lt → l + m ≤ lt + mt →
148 ∃∃T2. ⦃G, L⦄ ⊢ U1 ▶[l+m, lt+mt-(l+m)] U2 & ⬆[l, m] T2 ≡ U2.
149 #G #L #U1 #U2 #lt #mt #H elim H -G -L -U1 -U2 -lt -mt
150 [ * #i #G #L #lt #mt #T1 #l #m #H #_
151 [ lapply (lift_inv_sort2 … H) -H #H destruct /2 width=3 by ex2_intro/
152 | elim (lift_inv_lref2 … H) -H * #Hil #H destruct /3 width=3 by lift_lref_ge_minus, lift_lref_lt, ex2_intro/
153 | lapply (lift_inv_gref2 … H) -H #H destruct /2 width=3 by ex2_intro/
155 | #I #G #L #K #V #W #i #lt #mt #Hlti #Hilmt #HLK #HVW #T1 #l #m #H #Hllt #Hlmlmt
156 elim (lift_inv_lref2 … H) -H * #Hil #H destruct [ -V -Hilmt -Hlmlmt | -Hlti -Hllt ]
157 [ elim (ylt_yle_false … Hllt) -Hllt /3 width=3 by yle_ylt_trans, ylt_inj/
158 | elim (le_inv_plus_l … Hil) #Hlim #Hmi
159 elim (lift_split … HVW l (i-m+1) ? ? ?) [2,3,4: /2 width=1 by le_S_S, le_S/ ] -Hlim
160 #T2 #_ >plus_minus // <minus_minus /2 width=1 by le_S/ <minus_n_n <plus_n_O #H -Hmi
161 @(ex2_intro … H) -H @(cpy_subst … HLK HVW) /2 width=1 by yle_inj/ >ymax_pre_sn_comm // (**) (* explicit constructor *)
163 | #a #I #G #L #W1 #W2 #U1 #U2 #lt #mt #_ #_ #IHW12 #IHU12 #X #l #m #H #Hllt #Hlmlmt
164 elim (lift_inv_bind2 … H) -H #V1 #T1 #HVW1 #HTU1 #H destruct
165 elim (IHW12 … HVW1) -V1 -IHW12 //
166 elim (IHU12 … HTU1) -T1 -IHU12 /2 width=1 by yle_succ/
167 <yplus_inj >yplus_SO2 >yplus_succ1 >yplus_succ1
168 /3 width=2 by cpy_bind, lift_bind, ex2_intro/
169 | #I #G #L #W1 #W2 #U1 #U2 #lt #mt #_ #_ #IHW12 #IHU12 #X #l #m #H #Hllt #Hlmlmt
170 elim (lift_inv_flat2 … H) -H #V1 #T1 #HVW1 #HTU1 #H destruct
171 elim (IHW12 … HVW1) -V1 -IHW12 // elim (IHU12 … HTU1) -T1 -IHU12
172 /3 width=2 by cpy_flat, lift_flat, ex2_intro/
176 lemma cpy_fwd_tw: ∀G,L,T1,T2,l,m. ⦃G, L⦄ ⊢ T1 ▶[l, m] T2 → ♯{T1} ≤ ♯{T2}.
177 #G #L #T1 #T2 #l #m #H elim H -G -L -T1 -T2 -l -m normalize
178 /3 width=1 by monotonic_le_plus_l, le_plus/
181 (* Basic inversion lemmas ***************************************************)
183 fact cpy_inv_atom1_aux: ∀G,L,T1,T2,l,m. ⦃G, L⦄ ⊢ T1 ▶[l, m] T2 → ∀J. T1 = ⓪{J} →
185 ∃∃I,K,V,i. l ≤ yinj i & i < l + m &
189 #G #L #T1 #T2 #l #m * -G -L -T1 -T2 -l -m
190 [ #I #G #L #l #m #J #H destruct /2 width=1 by or_introl/
191 | #I #G #L #K #V #T2 #i #l #m #Hli #Hilm #HLK #HVT2 #J #H destruct /3 width=9 by ex5_4_intro, or_intror/
192 | #a #I #G #L #V1 #V2 #T1 #T2 #l #m #_ #_ #J #H destruct
193 | #I #G #L #V1 #V2 #T1 #T2 #l #m #_ #_ #J #H destruct
197 lemma cpy_inv_atom1: ∀I,G,L,T2,l,m. ⦃G, L⦄ ⊢ ⓪{I} ▶[l, m] T2 →
199 ∃∃J,K,V,i. l ≤ yinj i & i < l + m &
203 /2 width=4 by cpy_inv_atom1_aux/ qed-.
205 (* Basic_1: was: subst1_gen_sort *)
206 lemma cpy_inv_sort1: ∀G,L,T2,k,l,m. ⦃G, L⦄ ⊢ ⋆k ▶[l, m] T2 → T2 = ⋆k.
207 #G #L #T2 #k #l #m #H
208 elim (cpy_inv_atom1 … H) -H //
209 * #I #K #V #i #_ #_ #_ #_ #H destruct
212 (* Basic_1: was: subst1_gen_lref *)
213 lemma cpy_inv_lref1: ∀G,L,T2,i,l,m. ⦃G, L⦄ ⊢ #i ▶[l, m] T2 →
215 ∃∃I,K,V. l ≤ i & i < l + m &
218 #G #L #T2 #i #l #m #H
219 elim (cpy_inv_atom1 … H) -H /2 width=1 by or_introl/
220 * #I #K #V #j #Hlj #Hjlm #HLK #HVT2 #H destruct /3 width=5 by ex4_3_intro, or_intror/
223 lemma cpy_inv_gref1: ∀G,L,T2,p,l,m. ⦃G, L⦄ ⊢ §p ▶[l, m] T2 → T2 = §p.
224 #G #L #T2 #p #l #m #H
225 elim (cpy_inv_atom1 … H) -H //
226 * #I #K #V #i #_ #_ #_ #_ #H destruct
229 fact cpy_inv_bind1_aux: ∀G,L,U1,U2,l,m. ⦃G, L⦄ ⊢ U1 ▶[l, m] U2 →
230 ∀a,I,V1,T1. U1 = ⓑ{a,I}V1.T1 →
231 ∃∃V2,T2. ⦃G, L⦄ ⊢ V1 ▶[l, m] V2 &
232 ⦃G, L. ⓑ{I}V1⦄ ⊢ T1 ▶[⫯l, m] T2 &
234 #G #L #U1 #U2 #l #m * -G -L -U1 -U2 -l -m
235 [ #I #G #L #l #m #b #J #W1 #U1 #H destruct
236 | #I #G #L #K #V #W #i #l #m #_ #_ #_ #_ #b #J #W1 #U1 #H destruct
237 | #a #I #G #L #V1 #V2 #T1 #T2 #l #m #HV12 #HT12 #b #J #W1 #U1 #H destruct /2 width=5 by ex3_2_intro/
238 | #I #G #L #V1 #V2 #T1 #T2 #l #m #_ #_ #b #J #W1 #U1 #H destruct
242 lemma cpy_inv_bind1: ∀a,I,G,L,V1,T1,U2,l,m. ⦃G, L⦄ ⊢ ⓑ{a,I} V1. T1 ▶[l, m] U2 →
243 ∃∃V2,T2. ⦃G, L⦄ ⊢ V1 ▶[l, m] V2 &
244 ⦃G, L.ⓑ{I}V1⦄ ⊢ T1 ▶[⫯l, m] T2 &
246 /2 width=3 by cpy_inv_bind1_aux/ qed-.
248 fact cpy_inv_flat1_aux: ∀G,L,U1,U2,l,m. ⦃G, L⦄ ⊢ U1 ▶[l, m] U2 →
249 ∀I,V1,T1. U1 = ⓕ{I}V1.T1 →
250 ∃∃V2,T2. ⦃G, L⦄ ⊢ V1 ▶[l, m] V2 &
251 ⦃G, L⦄ ⊢ T1 ▶[l, m] T2 &
253 #G #L #U1 #U2 #l #m * -G -L -U1 -U2 -l -m
254 [ #I #G #L #l #m #J #W1 #U1 #H destruct
255 | #I #G #L #K #V #W #i #l #m #_ #_ #_ #_ #J #W1 #U1 #H destruct
256 | #a #I #G #L #V1 #V2 #T1 #T2 #l #m #_ #_ #J #W1 #U1 #H destruct
257 | #I #G #L #V1 #V2 #T1 #T2 #l #m #HV12 #HT12 #J #W1 #U1 #H destruct /2 width=5 by ex3_2_intro/
261 lemma cpy_inv_flat1: ∀I,G,L,V1,T1,U2,l,m. ⦃G, L⦄ ⊢ ⓕ{I} V1. T1 ▶[l, m] U2 →
262 ∃∃V2,T2. ⦃G, L⦄ ⊢ V1 ▶[l, m] V2 &
263 ⦃G, L⦄ ⊢ T1 ▶[l, m] T2 &
265 /2 width=3 by cpy_inv_flat1_aux/ qed-.
268 fact cpy_inv_refl_O2_aux: ∀G,L,T1,T2,l,m. ⦃G, L⦄ ⊢ T1 ▶[l, m] T2 → m = 0 → T1 = T2.
269 #G #L #T1 #T2 #l #m #H elim H -G -L -T1 -T2 -l -m
271 | #I #G #L #K #V #W #i #l #m #Hli #Hilm #_ #_ #H destruct
272 elim (ylt_yle_false … Hli) -Hli //
273 | /3 width=1 by eq_f2/
274 | /3 width=1 by eq_f2/
278 lemma cpy_inv_refl_O2: ∀G,L,T1,T2,l. ⦃G, L⦄ ⊢ T1 ▶[l, 0] T2 → T1 = T2.
279 /2 width=6 by cpy_inv_refl_O2_aux/ qed-.
281 (* Basic_1: was: subst1_gen_lift_eq *)
282 lemma cpy_inv_lift1_eq: ∀G,T1,U1,l,m. ⬆[l, m] T1 ≡ U1 →
283 ∀L,U2. ⦃G, L⦄ ⊢ U1 ▶[l, m] U2 → U1 = U2.
284 #G #T1 #U1 #l #m #HTU1 #L #U2 #HU12 elim (cpy_fwd_up … HU12 … HTU1) -HU12 -HTU1
285 /2 width=4 by cpy_inv_refl_O2/
288 (* Basic_1: removed theorems 25:
289 subst0_gen_sort subst0_gen_lref subst0_gen_head subst0_gen_lift_lt
290 subst0_gen_lift_false subst0_gen_lift_ge subst0_refl subst0_trans
291 subst0_lift_lt subst0_lift_ge subst0_lift_ge_S subst0_lift_ge_s
292 subst0_subst0 subst0_subst0_back subst0_weight_le subst0_weight_lt
293 subst0_confluence_neq subst0_confluence_eq subst0_tlt_head
294 subst0_confluence_lift subst0_tlt
295 subst1_head subst1_gen_head subst1_lift_S subst1_confluence_lift