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/relocation/rtmap_coafter.ma".
16 include "static_2/notation/relations/rdropstar_3.ma".
17 include "static_2/notation/relations/rdropstar_4.ma".
18 include "static_2/relocation/seq.ma".
19 include "static_2/relocation/lifts_bind.ma".
21 (* GENERIC SLICING FOR LOCAL ENVIRONMENTS ***********************************)
23 (* Basic_1: includes: drop_skip_bind drop1_skip_bind *)
24 (* Basic_2A1: includes: drop_atom drop_pair drop_drop drop_skip
25 drop_refl_atom_O2 drop_drop_lt drop_skip_lt
27 inductive drops (b:bool): rtmap → relation lenv ≝
28 | drops_atom: ∀f. (b = Ⓣ → 𝐈⦃f⦄) → drops b (f) (⋆) (⋆)
29 | drops_drop: ∀f,I,L1,L2. drops b f L1 L2 → drops b (↑f) (L1.ⓘ{I}) L2
30 | drops_skip: ∀f,I1,I2,L1,L2.
31 drops b f L1 L2 → ⬆*[f] I2 ≘ I1 →
32 drops b (⫯f) (L1.ⓘ{I1}) (L2.ⓘ{I2})
35 interpretation "uniform slicing (local environment)"
36 'RDropStar i L1 L2 = (drops true (uni i) L1 L2).
38 interpretation "generic slicing (local environment)"
39 'RDropStar b f L1 L2 = (drops b f L1 L2).
41 definition d_liftable1: predicate (relation2 lenv term) ≝
42 λR. ∀K,T. R K T → ∀b,f,L. ⬇*[b,f] L ≘ K →
43 ∀U. ⬆*[f] T ≘ U → R L U.
45 definition d_liftable1_isuni: predicate (relation2 lenv term) ≝
46 λR. ∀K,T. R K T → ∀b,f,L. ⬇*[b,f] L ≘ K → 𝐔⦃f⦄ →
47 ∀U. ⬆*[f] T ≘ U → R L U.
49 definition d_deliftable1: predicate (relation2 lenv term) ≝
50 λR. ∀L,U. R L U → ∀b,f,K. ⬇*[b,f] L ≘ K →
51 ∀T. ⬆*[f] T ≘ U → R K T.
53 definition d_deliftable1_isuni: predicate (relation2 lenv term) ≝
54 λR. ∀L,U. R L U → ∀b,f,K. ⬇*[b,f] L ≘ K → 𝐔⦃f⦄ →
55 ∀T. ⬆*[f] T ≘ U → R K T.
57 definition d_liftable2_sn: ∀C:Type[0]. ∀S:rtmap → relation C.
58 predicate (lenv → relation C) ≝
59 λC,S,R. ∀K,T1,T2. R K T1 T2 → ∀b,f,L. ⬇*[b,f] L ≘ K →
61 ∃∃U2. S f T2 U2 & R L U1 U2.
63 definition d_deliftable2_sn: ∀C:Type[0]. ∀S:rtmap → relation C.
64 predicate (lenv → relation C) ≝
65 λC,S,R. ∀L,U1,U2. R L U1 U2 → ∀b,f,K. ⬇*[b,f] L ≘ K →
67 ∃∃T2. S f T2 U2 & R K T1 T2.
69 definition d_liftable2_bi: ∀C:Type[0]. ∀S:rtmap → relation C.
70 predicate (lenv → relation C) ≝
71 λC,S,R. ∀K,T1,T2. R K T1 T2 → ∀b,f,L. ⬇*[b,f] L ≘ K →
73 ∀U2. S f T2 U2 → R L U1 U2.
75 definition d_deliftable2_bi: ∀C:Type[0]. ∀S:rtmap → relation C.
76 predicate (lenv → relation C) ≝
77 λC,S,R. ∀L,U1,U2. R L U1 U2 → ∀b,f,K. ⬇*[b,f] L ≘ K →
79 ∀T2. S f T2 U2 → R K T1 T2.
81 definition co_dropable_sn: predicate (rtmap → relation lenv) ≝
82 λR. ∀b,f,L1,K1. ⬇*[b,f] L1 ≘ K1 → 𝐔⦃f⦄ →
83 ∀f2,L2. R f2 L1 L2 → ∀f1. f ~⊚ f1 ≘ f2 →
84 ∃∃K2. R f1 K1 K2 & ⬇*[b,f] L2 ≘ K2.
86 definition co_dropable_dx: predicate (rtmap → relation lenv) ≝
87 λR. ∀f2,L1,L2. R f2 L1 L2 →
88 ∀b,f,K2. ⬇*[b,f] L2 ≘ K2 → 𝐔⦃f⦄ →
90 ∃∃K1. ⬇*[b,f] L1 ≘ K1 & R f1 K1 K2.
92 definition co_dedropable_sn: predicate (rtmap → relation lenv) ≝
93 λR. ∀b,f,L1,K1. ⬇*[b,f] L1 ≘ K1 → ∀f1,K2. R f1 K1 K2 →
95 ∃∃L2. R f2 L1 L2 & ⬇*[b,f] L2 ≘ K2 & L1 ≡[f] L2.
97 (* Basic properties *********************************************************)
99 lemma drops_atom_F: ∀f. ⬇*[Ⓕ,f] ⋆ ≘ ⋆.
100 #f @drops_atom #H destruct
103 lemma drops_eq_repl_back: ∀b,L1,L2. eq_repl_back … (λf. ⬇*[b,f] L1 ≘ L2).
104 #b #L1 #L2 #f1 #H elim H -f1 -L1 -L2
105 [ /4 width=3 by drops_atom, isid_eq_repl_back/
106 | #f1 #I #L1 #L2 #_ #IH #f2 #H elim (eq_inv_nx … H) -H
107 /3 width=3 by drops_drop/
108 | #f1 #I1 #I2 #L1 #L2 #_ #HI #IH #f2 #H elim (eq_inv_px … H) -H
109 /3 width=3 by drops_skip, liftsb_eq_repl_back/
113 lemma drops_eq_repl_fwd: ∀b,L1,L2. eq_repl_fwd … (λf. ⬇*[b,f] L1 ≘ L2).
114 #b #L1 #L2 @eq_repl_sym /2 width=3 by drops_eq_repl_back/ (**) (* full auto fails *)
117 (* Basic_2A1: includes: drop_FT *)
118 lemma drops_TF: ∀f,L1,L2. ⬇*[Ⓣ,f] L1 ≘ L2 → ⬇*[Ⓕ,f] L1 ≘ L2.
119 #f #L1 #L2 #H elim H -f -L1 -L2
120 /3 width=1 by drops_atom, drops_drop, drops_skip/
123 (* Basic_2A1: includes: drop_gen *)
124 lemma drops_gen: ∀b,f,L1,L2. ⬇*[Ⓣ,f] L1 ≘ L2 → ⬇*[b,f] L1 ≘ L2.
125 * /2 width=1 by drops_TF/
128 (* Basic_2A1: includes: drop_T *)
129 lemma drops_F: ∀b,f,L1,L2. ⬇*[b,f] L1 ≘ L2 → ⬇*[Ⓕ,f] L1 ≘ L2.
130 * /2 width=1 by drops_TF/
133 lemma d_liftable2_sn_bi: ∀C,S. (∀f,c. is_mono … (S f c)) →
134 ∀R. d_liftable2_sn C S R → d_liftable2_bi C S R.
135 #C #S #HS #R #HR #K #T1 #T2 #HT12 #b #f #L #HLK #U1 #HTU1 #U2 #HTU2
136 elim (HR … HT12 … HLK … HTU1) -HR -K -T1 #X #HTX #HUX
137 <(HS … HTX … HTU2) -T2 -U2 -b -f //
140 lemma d_deliftable2_sn_bi: ∀C,S. (∀f. is_inj2 … (S f)) →
141 ∀R. d_deliftable2_sn C S R → d_deliftable2_bi C S R.
142 #C #S #HS #R #HR #L #U1 #U2 #HU12 #b #f #K #HLK #T1 #HTU1 #T2 #HTU2
143 elim (HR … HU12 … HLK … HTU1) -HR -L -U1 #X #HUX #HTX
144 <(HS … HUX … HTU2) -U2 -T2 -b -f //
147 (* Basic inversion lemmas ***************************************************)
149 fact drops_inv_atom1_aux: ∀b,f,X,Y. ⬇*[b,f] X ≘ Y → X = ⋆ →
150 Y = ⋆ ∧ (b = Ⓣ → 𝐈⦃f⦄).
151 #b #f #X #Y * -f -X -Y
152 [ /3 width=1 by conj/
153 | #f #I #L1 #L2 #_ #H destruct
154 | #f #I1 #I2 #L1 #L2 #_ #_ #H destruct
158 (* Basic_1: includes: drop_gen_sort *)
159 (* Basic_2A1: includes: drop_inv_atom1 *)
160 lemma drops_inv_atom1: ∀b,f,Y. ⬇*[b,f] ⋆ ≘ Y → Y = ⋆ ∧ (b = Ⓣ → 𝐈⦃f⦄).
161 /2 width=3 by drops_inv_atom1_aux/ qed-.
163 fact drops_inv_drop1_aux: ∀b,f,X,Y. ⬇*[b,f] X ≘ Y → ∀g,I,K. X = K.ⓘ{I} → f = ↑g →
165 #b #f #X #Y * -f -X -Y
166 [ #f #Hf #g #J #K #H destruct
167 | #f #I #L1 #L2 #HL #g #J #K #H1 #H2 <(injective_next … H2) -g destruct //
168 | #f #I1 #I2 #L1 #L2 #_ #_ #g #J #K #_ #H2 elim (discr_push_next … H2)
172 (* Basic_1: includes: drop_gen_drop *)
173 (* Basic_2A1: includes: drop_inv_drop1_lt drop_inv_drop1 *)
174 lemma drops_inv_drop1: ∀b,f,I,K,Y. ⬇*[b,↑f] K.ⓘ{I} ≘ Y → ⬇*[b,f] K ≘ Y.
175 /2 width=6 by drops_inv_drop1_aux/ qed-.
177 fact drops_inv_skip1_aux: ∀b,f,X,Y. ⬇*[b,f] X ≘ Y → ∀g,I1,K1. X = K1.ⓘ{I1} → f = ⫯g →
178 ∃∃I2,K2. ⬇*[b,g] K1 ≘ K2 & ⬆*[g] I2 ≘ I1 & Y = K2.ⓘ{I2}.
179 #b #f #X #Y * -f -X -Y
180 [ #f #Hf #g #J1 #K1 #H destruct
181 | #f #I #L1 #L2 #_ #g #J1 #K1 #_ #H2 elim (discr_next_push … H2)
182 | #f #I1 #I2 #L1 #L2 #HL #HI #g #J1 #K1 #H1 #H2 <(injective_push … H2) -g destruct
183 /2 width=5 by ex3_2_intro/
187 (* Basic_1: includes: drop_gen_skip_l *)
188 (* Basic_2A1: includes: drop_inv_skip1 *)
189 lemma drops_inv_skip1: ∀b,f,I1,K1,Y. ⬇*[b,⫯f] K1.ⓘ{I1} ≘ Y →
190 ∃∃I2,K2. ⬇*[b,f] K1 ≘ K2 & ⬆*[f] I2 ≘ I1 & Y = K2.ⓘ{I2}.
191 /2 width=5 by drops_inv_skip1_aux/ qed-.
193 fact drops_inv_skip2_aux: ∀b,f,X,Y. ⬇*[b,f] X ≘ Y → ∀g,I2,K2. Y = K2.ⓘ{I2} → f = ⫯g →
194 ∃∃I1,K1. ⬇*[b,g] K1 ≘ K2 & ⬆*[g] I2 ≘ I1 & X = K1.ⓘ{I1}.
195 #b #f #X #Y * -f -X -Y
196 [ #f #Hf #g #J2 #K2 #H destruct
197 | #f #I #L1 #L2 #_ #g #J2 #K2 #_ #H2 elim (discr_next_push … H2)
198 | #f #I1 #I2 #L1 #L2 #HL #HV #g #J2 #K2 #H1 #H2 <(injective_push … H2) -g destruct
199 /2 width=5 by ex3_2_intro/
203 (* Basic_1: includes: drop_gen_skip_r *)
204 (* Basic_2A1: includes: drop_inv_skip2 *)
205 lemma drops_inv_skip2: ∀b,f,I2,X,K2. ⬇*[b,⫯f] X ≘ K2.ⓘ{I2} →
206 ∃∃I1,K1. ⬇*[b,f] K1 ≘ K2 & ⬆*[f] I2 ≘ I1 & X = K1.ⓘ{I1}.
207 /2 width=5 by drops_inv_skip2_aux/ qed-.
209 (* Basic forward lemmas *****************************************************)
211 fact drops_fwd_drop2_aux: ∀b,f2,X,Y. ⬇*[b,f2] X ≘ Y → ∀I,K. Y = K.ⓘ{I} →
212 ∃∃f1,f. 𝐈⦃f1⦄ & f2 ⊚ ↑f1 ≘ f & ⬇*[b,f] X ≘ K.
213 #b #f2 #X #Y #H elim H -f2 -X -Y
214 [ #f2 #Hf2 #J #K #H destruct
215 | #f2 #I #L1 #L2 #_ #IHL #J #K #H elim (IHL … H) -IHL
216 /3 width=7 by after_next, ex3_2_intro, drops_drop/
217 | #f2 #I1 #I2 #L1 #L2 #HL #_ #_ #J #K #H destruct
218 lapply (after_isid_dx 𝐈𝐝 … f2) /3 width=9 by after_push, ex3_2_intro, drops_drop/
222 lemma drops_fwd_drop2: ∀b,f2,I,X,K. ⬇*[b,f2] X ≘ K.ⓘ{I} →
223 ∃∃f1,f. 𝐈⦃f1⦄ & f2 ⊚ ↑f1 ≘ f & ⬇*[b,f] X ≘ K.
224 /2 width=4 by drops_fwd_drop2_aux/ qed-.
226 (* Properties with test for identity ****************************************)
228 (* Basic_2A1: includes: drop_refl *)
229 lemma drops_refl: ∀b,L,f. 𝐈⦃f⦄ → ⬇*[b,f] L ≘ L.
230 #b #L elim L -L /2 width=1 by drops_atom/
231 #L #I #IHL #f #Hf elim (isid_inv_gen … Hf) -Hf
232 /3 width=1 by drops_skip, liftsb_refl/
235 (* Forward lemmas test for identity *****************************************)
237 (* Basic_1: includes: drop_gen_refl *)
238 (* Basic_2A1: includes: drop_inv_O2 *)
239 lemma drops_fwd_isid: ∀b,f,L1,L2. ⬇*[b,f] L1 ≘ L2 → 𝐈⦃f⦄ → L1 = L2.
240 #b #f #L1 #L2 #H elim H -f -L1 -L2 //
241 [ #f #I #L1 #L2 #_ #_ #H elim (isid_inv_next … H) //
242 | /5 width=5 by isid_inv_push, liftsb_fwd_isid, eq_f2, sym_eq/
246 lemma drops_after_fwd_drop2: ∀b,f2,I,X,K. ⬇*[b,f2] X ≘ K.ⓘ{I} →
247 ∀f1,f. 𝐈⦃f1⦄ → f2 ⊚ ↑f1 ≘ f → ⬇*[b,f] X ≘ K.
248 #b #f2 #I #X #K #H #f1 #f #Hf1 #Hf elim (drops_fwd_drop2 … H) -H
249 #g1 #g #Hg1 #Hg #HK lapply (after_mono_eq … Hg … Hf ??) -Hg -Hf
250 /3 width=5 by drops_eq_repl_back, isid_inv_eq_repl, eq_next/
253 (* Forward lemmas with test for finite colength *****************************)
255 lemma drops_fwd_isfin: ∀f,L1,L2. ⬇*[Ⓣ,f] L1 ≘ L2 → 𝐅⦃f⦄.
256 #f #L1 #L2 #H elim H -f -L1 -L2
257 /3 width=1 by isfin_next, isfin_push, isfin_isid/
260 (* Properties with test for uniformity **************************************)
262 lemma drops_isuni_ex: ∀f. 𝐔⦃f⦄ → ∀L. ∃K. ⬇*[Ⓕ,f] L ≘ K.
263 #f #H elim H -f /4 width=2 by drops_refl, drops_TF, ex_intro/
264 #f #_ #g #H #IH destruct * /2 width=2 by ex_intro/
265 #L #I elim (IH L) -IH /3 width=2 by drops_drop, ex_intro/
268 (* Inversion lemmas with test for uniformity ********************************)
270 lemma drops_inv_isuni: ∀f,L1,L2. ⬇*[Ⓣ,f] L1 ≘ L2 → 𝐔⦃f⦄ →
272 ∃∃g,I,K. ⬇*[Ⓣ,g] K ≘ L2 & 𝐔⦃g⦄ & L1 = K.ⓘ{I} & f = ↑g.
273 #f #L1 #L2 * -f -L1 -L2
274 [ /4 width=1 by or_introl, conj/
275 | /4 width=7 by isuni_inv_next, ex4_3_intro, or_intror/
276 | /7 width=6 by drops_fwd_isid, liftsb_fwd_isid, isuni_inv_push, isid_push, or_introl, conj, eq_f2, sym_eq/
280 (* Basic_2A1: was: drop_inv_O1_pair1 *)
281 lemma drops_inv_bind1_isuni: ∀b,f,I,K,L2. 𝐔⦃f⦄ → ⬇*[b,f] K.ⓘ{I} ≘ L2 →
282 (𝐈⦃f⦄ ∧ L2 = K.ⓘ{I}) ∨
283 ∃∃g. 𝐔⦃g⦄ & ⬇*[b,g] K ≘ L2 & f = ↑g.
284 #b #f #I #K #L2 #Hf #H elim (isuni_split … Hf) -Hf * #g #Hg #H0 destruct
285 [ lapply (drops_inv_skip1 … H) -H * #Z #Y #HY #HZ #H destruct
286 <(drops_fwd_isid … HY Hg) -Y >(liftsb_fwd_isid … HZ Hg) -Z
287 /4 width=3 by isid_push, or_introl, conj/
288 | lapply (drops_inv_drop1 … H) -H /3 width=4 by ex3_intro, or_intror/
292 (* Basic_2A1: was: drop_inv_O1_pair2 *)
293 lemma drops_inv_bind2_isuni: ∀b,f,I,K,L1. 𝐔⦃f⦄ → ⬇*[b,f] L1 ≘ K.ⓘ{I} →
294 (𝐈⦃f⦄ ∧ L1 = K.ⓘ{I}) ∨
295 ∃∃g,I1,K1. 𝐔⦃g⦄ & ⬇*[b,g] K1 ≘ K.ⓘ{I} & L1 = K1.ⓘ{I1} & f = ↑g.
297 [ #Hf #H elim (drops_inv_atom1 … H) -H #H destruct
298 | #L1 #I1 #Hf #H elim (drops_inv_bind1_isuni … Hf H) -Hf -H *
299 [ #Hf #H destruct /3 width=1 by or_introl, conj/
300 | /3 width=7 by ex4_3_intro, or_intror/
305 lemma drops_inv_bind2_isuni_next: ∀b,f,I,K,L1. 𝐔⦃f⦄ → ⬇*[b,↑f] L1 ≘ K.ⓘ{I} →
306 ∃∃I1,K1. ⬇*[b,f] K1 ≘ K.ⓘ{I} & L1 = K1.ⓘ{I1}.
307 #b #f #I #K #L1 #Hf #H elim (drops_inv_bind2_isuni … H) -H /2 width=3 by isuni_next/ -Hf *
308 [ #H elim (isid_inv_next … H) -H //
309 | /2 width=4 by ex2_2_intro/
313 fact drops_inv_TF_aux: ∀f,L1,L2. ⬇*[Ⓕ,f] L1 ≘ L2 → 𝐔⦃f⦄ →
314 ∀I,K. L2 = K.ⓘ{I} → ⬇*[Ⓣ,f] L1 ≘ K.ⓘ{I}.
315 #f #L1 #L2 #H elim H -f -L1 -L2
316 [ #f #_ #_ #J #K #H destruct
317 | #f #I #L1 #L2 #_ #IH #Hf #J #K #H destruct
318 /4 width=3 by drops_drop, isuni_inv_next/
319 | #f #I1 #I2 #L1 #L2 #HL12 #HI21 #_ #Hf #J #K #H destruct
320 lapply (isuni_inv_push … Hf ??) -Hf [1,2: // ] #Hf
321 <(drops_fwd_isid … HL12) -K // <(liftsb_fwd_isid … HI21) -I1
322 /3 width=3 by drops_refl, isid_push/
326 (* Basic_2A1: includes: drop_inv_FT *)
327 lemma drops_inv_TF: ∀f,I,L,K. ⬇*[Ⓕ,f] L ≘ K.ⓘ{I} → 𝐔⦃f⦄ → ⬇*[Ⓣ,f] L ≘ K.ⓘ{I}.
328 /2 width=3 by drops_inv_TF_aux/ qed-.
330 (* Basic_2A1: includes: drop_inv_gen *)
331 lemma drops_inv_gen: ∀b,f,I,L,K. ⬇*[b,f] L ≘ K.ⓘ{I} → 𝐔⦃f⦄ → ⬇*[Ⓣ,f] L ≘ K.ⓘ{I}.
332 * /2 width=1 by drops_inv_TF/
335 (* Basic_2A1: includes: drop_inv_T *)
336 lemma drops_inv_F: ∀b,f,I,L,K. ⬇*[Ⓕ,f] L ≘ K.ⓘ{I} → 𝐔⦃f⦄ → ⬇*[b,f] L ≘ K.ⓘ{I}.
337 * /2 width=1 by drops_inv_TF/
340 (* Forward lemmas with test for uniformity **********************************)
342 (* Basic_1: was: drop_S *)
343 (* Basic_2A1: was: drop_fwd_drop2 *)
344 lemma drops_isuni_fwd_drop2: ∀b,f,I,X,K. 𝐔⦃f⦄ → ⬇*[b,f] X ≘ K.ⓘ{I} → ⬇*[b,↑f] X ≘ K.
345 /3 width=7 by drops_after_fwd_drop2, after_isid_isuni/ qed-.
347 (* Inversion lemmas with uniform relocations ********************************)
349 lemma drops_inv_atom2: ∀b,L,f. ⬇*[b,f] L ≘ ⋆ →
350 ∃∃n,f1. ⬇*[b,𝐔❴n❵] L ≘ ⋆ & 𝐔❴n❵ ⊚ f1 ≘ f.
352 [ /3 width=4 by drops_atom, after_isid_sn, ex2_2_intro/
353 | #L #I #IH #f #H elim (pn_split f) * #g #H0 destruct
354 [ elim (drops_inv_skip1 … H) -H #J #K #_ #_ #H destruct
355 | lapply (drops_inv_drop1 … H) -H #HL
356 elim (IH … HL) -IH -HL /3 width=8 by drops_drop, after_next, ex2_2_intro/
361 lemma drops_inv_succ: ∀L1,L2,i. ⬇*[↑i] L1 ≘ L2 →
362 ∃∃I,K. ⬇*[i] K ≘ L2 & L1 = K.ⓘ{I}.
363 #L1 #L2 #i #H elim (drops_inv_isuni … H) -H // *
364 [ #H elim (isid_inv_next … H) -H //
365 | /2 width=4 by ex2_2_intro/
369 (* Properties with uniform relocations **************************************)
371 lemma drops_F_uni: ∀L,i. ⬇*[Ⓕ,𝐔❴i❵] L ≘ ⋆ ∨ ∃∃I,K. ⬇*[i] L ≘ K.ⓘ{I}.
372 #L elim L -L /2 width=1 by or_introl/
373 #L #I #IH * /4 width=3 by drops_refl, ex1_2_intro, or_intror/
374 #i elim (IH i) -IH /3 width=1 by drops_drop, or_introl/
375 * /4 width=3 by drops_drop, ex1_2_intro, or_intror/
378 (* Basic_2A1: includes: drop_split *)
379 lemma drops_split_trans: ∀b,f,L1,L2. ⬇*[b,f] L1 ≘ L2 → ∀f1,f2. f1 ⊚ f2 ≘ f → 𝐔⦃f1⦄ →
380 ∃∃L. ⬇*[b,f1] L1 ≘ L & ⬇*[b,f2] L ≘ L2.
381 #b #f #L1 #L2 #H elim H -f -L1 -L2
382 [ #f #H0f #f1 #f2 #Hf #Hf1 @(ex2_intro … (⋆)) @drops_atom
384 #H elim (after_inv_isid3 … Hf H) -f //
385 | #f #I #L1 #L2 #HL12 #IHL12 #f1 #f2 #Hf #Hf1 elim (after_inv_xxn … Hf) -Hf [1,3: * |*: // ]
386 [ #g1 #g2 #Hf #H1 #H2 destruct
387 lapply (isuni_inv_push … Hf1 ??) -Hf1 [1,2: // ] #Hg1
389 /4 width=5 by drops_drop, drops_skip, liftsb_refl, isuni_isid, ex2_intro/
390 | #g1 #Hf #H destruct elim (IHL12 … Hf) -f
391 /3 width=5 by ex2_intro, drops_drop, isuni_inv_next/
393 | #f #I1 #I2 #L1 #L2 #_ #HI21 #IHL12 #f1 #f2 #Hf #Hf1 elim (after_inv_xxp … Hf) -Hf [2,3: // ]
394 #g1 #g2 #Hf #H1 #H2 destruct elim (liftsb_split_trans … HI21 … Hf) -HI21
395 elim (IHL12 … Hf) -f /3 width=5 by ex2_intro, drops_skip, isuni_fwd_push/
399 lemma drops_split_div: ∀b,f1,L1,L. ⬇*[b,f1] L1 ≘ L → ∀f2,f. f1 ⊚ f2 ≘ f → 𝐔⦃f2⦄ →
400 ∃∃L2. ⬇*[Ⓕ,f2] L ≘ L2 & ⬇*[Ⓕ,f] L1 ≘ L2.
401 #b #f1 #L1 #L #H elim H -f1 -L1 -L
402 [ #f1 #Hf1 #f2 #f #Hf #Hf2 @(ex2_intro … (⋆)) @drops_atom #H destruct
403 | #f1 #I #L1 #L #HL1 #IH #f2 #f #Hf #Hf2 elim (after_inv_nxx … Hf) -Hf [2,3: // ]
404 #g #Hg #H destruct elim (IH … Hg) -IH -Hg /3 width=5 by drops_drop, ex2_intro/
405 | #f1 #I1 #I #L1 #L #HL1 #HI1 #IH #f2 #f #Hf #Hf2
406 elim (after_inv_pxx … Hf) -Hf [1,3: * |*: // ]
407 #g2 #g #Hg #H2 #H0 destruct
408 [ lapply (isuni_inv_push … Hf2 ??) -Hf2 [1,2: // ] #Hg2 -IH
409 lapply (after_isid_inv_dx … Hg … Hg2) -Hg #Hg
410 /5 width=7 by drops_eq_repl_back, drops_F, drops_refl, drops_skip, liftsb_eq_repl_back, isid_push, ex2_intro/
411 | lapply (isuni_inv_next … Hf2 ??) -Hf2 [1,2: // ] #Hg2 -HL1 -HI1
412 elim (IH … Hg) -f1 /3 width=3 by drops_drop, ex2_intro/
417 (* Properties with application **********************************************)
419 lemma drops_tls_at: ∀f,i1,i2. @⦃i1,f⦄ ≘ i2 →
420 ∀b,L1,L2. ⬇*[b,⫱*[i2]f] L1 ≘ L2 →
421 ⬇*[b,⫯⫱*[↑i2]f] L1 ≘ L2.
422 /3 width=3 by drops_eq_repl_fwd, at_inv_tls/ qed-.
424 lemma drops_split_trans_bind2: ∀b,f,I,L,K0. ⬇*[b,f] L ≘ K0.ⓘ{I} → ∀i. @⦃O,f⦄ ≘ i →
425 ∃∃J,K. ⬇*[i]L ≘ K.ⓘ{J} & ⬇*[b,⫱*[↑i]f] K ≘ K0 & ⬆*[⫱*[↑i]f] I ≘ J.
426 #b #f #I #L #K0 #H #i #Hf
427 elim (drops_split_trans … H) -H [ |5: @(after_uni_dx … Hf) |2,3: skip ] /2 width=1 by after_isid_dx/ #Y #HLY #H
428 lapply (drops_tls_at … Hf … H) -H #H
429 elim (drops_inv_skip2 … H) -H #J #K #HK0 #HIJ #H destruct
430 /3 width=5 by drops_inv_gen, ex3_2_intro/
433 (* Properties with context-sensitive equivalence for terms ******************)
435 lemma ceq_lift_sn: d_liftable2_sn … liftsb ceq_ext.
436 #K #I1 #I2 #H <(ceq_ext_inv_eq … H) -I2
437 /2 width=3 by ex2_intro/ qed-.
439 lemma ceq_inv_lift_sn: d_deliftable2_sn … liftsb ceq_ext.
440 #L #J1 #J2 #H <(ceq_ext_inv_eq … H) -J2
441 /2 width=3 by ex2_intro/ qed-.
443 (* Note: d_deliftable2_sn cfull does not hold *)
444 lemma cfull_lift_sn: d_liftable2_sn … liftsb cfull.
445 #K #I1 #I2 #_ #b #f #L #_ #J1 #_ -K -I1 -b
446 elim (liftsb_total I2 f) /2 width=3 by ex2_intro/
449 (* Basic_2A1: removed theorems 12:
450 drops_inv_nil drops_inv_cons d1_liftable_liftables
451 drop_refl_atom_O2 drop_inv_pair1
452 drop_inv_Y1 drop_Y1 drop_O_Y drop_fwd_Y2
453 drop_fwd_length_minus2 drop_fwd_length_minus4
455 (* Basic_1: removed theorems 53:
456 drop1_gen_pnil drop1_gen_pcons drop1_getl_trans
457 drop_ctail drop_skip_flat
458 cimp_flat_sx cimp_flat_dx cimp_bind cimp_getl_conf
459 drop_clear drop_clear_O drop_clear_S
460 clear_gen_sort clear_gen_bind clear_gen_flat clear_gen_flat_r
461 clear_gen_all clear_clear clear_mono clear_trans clear_ctail clear_cle
462 getl_ctail_clen getl_gen_tail clear_getl_trans getl_clear_trans
463 getl_clear_bind getl_clear_conf getl_dec getl_drop getl_drop_conf_lt
464 getl_drop_conf_ge getl_conf_ge_drop getl_drop_conf_rev
465 drop_getl_trans_lt drop_getl_trans_le drop_getl_trans_ge
466 getl_drop_trans getl_flt getl_gen_all getl_gen_sort getl_gen_O
467 getl_gen_S getl_gen_2 getl_gen_flat getl_gen_bind getl_conf_le
468 getl_trans getl_refl getl_head getl_flat getl_ctail getl_mono