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.
7 ||A|| This file is distributed under the terms of the
8 \ / GNU General Public License Version 2
10 V_______________________________________________________________ *)
12 include "basics/finset.ma".
13 include "basics/star.ma".
16 inductive FType (O:Type[0]): Type[0] ≝
18 | arrow : FType O → FType O → FType O.
20 inductive T (O:Type[0]) (D:O → FinSet): Type[0] ≝
21 | Val: ∀o:O.carr (D o) → T O D (* a value in a finset *)
22 | Rel: nat → T O D (* DB index, base is 0 *)
23 | App: T O D → T O D → T O D (* function, argument *)
24 | Lambda: FType O → T O D → T O D (* type, body *)
25 | Vec: FType O → list (T O D) → T O D (* type, body *)
28 let rec FinSet_of_FType O (D:O→FinSet) (ty:FType O) on ty : FinSet ≝
31 |arrow ty1 ty2 ⇒ FinFun (FinSet_of_FType O D ty1) (FinSet_of_FType O D ty2)
36 let rec size O D (M:T O D) on M ≝
40 |App P Q ⇒ size O D P + size O D Q + 1
41 |Lambda Ty P ⇒ size O D P + 1
42 |Vec Ty v ⇒ foldr ?? (λx,a. size O D x + a) 0 v +1
46 (* axiom pos_size: ∀M. 1 ≤ size M. *)
48 theorem Telim_size: ∀O,D.∀P: T O D → Prop.
49 (∀M. (∀N. size O D N < size O D M → P N) → P M) → ∀M. P M.
50 #O #D #P #H #M (cut (∀p,N. size O D N = p → P N))
52 #p @(nat_elim1 p) #m #H1 #N #sizeN @H #N0 #Hlt @(H1 (size O D N0)) //
56 ∀O: Type[0].∀D:O→FinSet.∀P:T O D→Prop.
57 (∀o:O.∀x:D o.P (Val O D o x)) →
59 (∀m,n:T O D.P m→P n→P (App O D m n)) →
60 (∀Ty:FType O.∀m:T O D.P m→P(Lambda O D Ty m)) →
61 (∀Ty:FType O.∀v:list (T O D).
62 (∀x:T O D. mem ? x v → P x) → P(Vec O D Ty v)) →
64 #O #D #P #Hval #Hrel #Happ #Hlam #Hvec @Telim_size #x cases x //
65 [ (* app *) #m #n #Hind @Happ @Hind // /2 by le_minus_to_plus/
66 | (* lam *) #ty #m #Hind @Hlam @Hind normalize //
67 | (* vec *) #ty #v #Hind @Hvec #x lapply Hind elim v
69 |#hd #tl #Hind1 #Hind2 *
70 [#Hx >Hx @Hind2 normalize //
71 |@Hind1 #N #H @Hind2 @(lt_to_le_to_lt … H) normalize //
78 (* arguments: k is the nesting depth (starts from 0), p is the lift *)
79 let rec lift O D t k p on t ≝
81 [ Val o a ⇒ Val O D o a
82 | Rel n ⇒ if (leb k n) then Rel O D (n+p) else Rel O D n
83 | App m n ⇒ App O D (lift O D m k p) (lift O D n k p)
84 | Lambda Ty n ⇒ Lambda O D Ty (lift O D n (S k) p)
85 | Vec Ty v ⇒ Vec O D Ty (map ?? (λx. lift O D x k p) v)
88 notation "↑ ^ n ( M )" non associative with precedence 40 for @{'Lift 0 $n $M}.
89 notation "↑ _ k ^ n ( M )" non associative with precedence 40 for @{'Lift $n $k $M}.
91 interpretation "Lift" 'Lift n k M = (lift ?? M k n).
93 let rec subst O D t k s on t ≝
95 [ Val o a ⇒ Val O D o a
96 | Rel n ⇒ if (leb k n) then
97 (if (eqb k n) then lift O D s 0 n else Rel O D (n-1))
99 | App m n ⇒ App O D (subst O D m k s) (subst O D n k s)
100 | Lambda T n ⇒ Lambda O D T (subst O D n (S k) s)
101 | Vec T v ⇒ Vec O D T (map ?? (λx. subst O D x k s) v)
104 (* notation "hvbox(M break [ k ≝ N ])"
105 non associative with precedence 90
106 for @{'Subst1 $M $k $N}. *)
108 interpretation "Subst" 'Subst1 M k N = (subst M k N).
111 let rec closed_k O D (t: T O D) k on t ≝
115 | App m n ⇒ (closed_k O D m k) ∧ (closed_k O D n k)
116 | Lambda T n ⇒ closed_k O D n (k+1)
117 | Vec T v ⇒ closed_list O D v k
120 and closed_list O D (l: list (T O D)) k on l ≝
123 | cons hd tl ⇒ closed_k O D hd k ∧ closed_list O D tl k
127 inductive is_closed (O:Type[0]) (D:O→FinSet): nat → T O D → Prop ≝
128 | cval : ∀k,o,a.is_closed O D k (Val O D o a)
129 | cval : ∀k,n. n < k → is_closed O D k (Rel O D n)
130 | capp : ∀k,n,m. is_closed O D k m → is_closed O D k n →
131 is_closed O D k (App O D m n)
132 | clam : ∀T,k,m. is_closed O D (k+1) m → is_closed O D k (Lambda O D T m)
133 | cvec: ∀T,k,v. (∀m. mem ? m v → is_closed O D k m) →
134 is_closed O D k (Vec O D T v).
136 lemma is_closed_rel: ∀O,D,n,k.
137 is_closed O D k (Rel O D n) → n < k.
138 #O #D #n #k #H inversion H
139 [#k0 #o #a #eqk #H destruct
140 |#k0 #n0 #ltn0 #eqk #H destruct //
141 |#k0 #M #N #_ #_ #_ #H destruct
142 |#T #k0 #M #_ #_ #H destruct
143 |#T #k0 #v #_ #_ #H destruct
148 (*** properties of lift and subst ***)
150 lemma lift_0: ∀O,D.∀t:T O D.∀k. lift O D t k 0 = t.
151 #O #D #t @(T_elim … t) normalize //
152 [#n #k cases (leb k n) normalize //
153 |#o #v #Hind #k @eq_f lapply Hind -Hind elim v //
154 #hd #tl #Hind #Hind1 normalize @eq_f2
155 [@Hind1 %1 //|@Hind #x #Hx @Hind1 %2 //]
159 axiom lift_closed: ∀O,D.∀t:T O D.∀k,p.
160 is_closed O D 0 t → lift O D t k p = t.
162 #O #D #t @(T_elim … t) normalize //
164 |#o #v #Hind #k @eq_f lapply Hind -Hind elim v //
165 #hd #tl #Hind #Hind1 normalize @eq_f2
166 [@Hind1 %1 //|@Hind #x #Hx @Hind1 %2 //]
170 let rec to_T O D ty on ty: FinSet_of_FType O D ty → T O D ≝
171 match ty return (λty.FinSet_of_FType O D ty → T O D) with
172 [atom o ⇒ λa.Val O D o a
173 |arrow ty1 ty2 ⇒ λa:FinFun ??.Vec O D ty1
174 (map ((FinSet_of_FType O D ty1)×(FinSet_of_FType O D ty2))
175 (T O D) (λp.to_T O D ty2 (snd … p)) (pi1 … a))
179 axiom inj_to_T: ∀O,D,ty,a1,a2. to_T O D ty a1 = to_T O D ty a2 → a1 = a2.
181 let rec assoc (A:FinSet) (B:Type[0]) (a:A) l1 l2 on l1 : option B ≝
184 | cons hd1 tl1 ⇒ match l2 with
186 | cons hd2 tl2 ⇒ if a==hd1 then Some ? hd2 else assoc A B a tl1 tl2
190 lemma same_assoc: ∀A,B,a,l1,v1,v2,N,N1.
191 assoc A B a l1 (v1@N::v2) = Some ? N ∧ assoc A B a l1 (v1@N1::v2) = Some ? N1
192 ∨ assoc A B a l1 (v1@N::v2) = assoc A B a l1 (v1@N1::v2).
193 #A #B #a #l1 #v1 #v2 #N #N1 lapply v1 -v1 elim l1
194 [#v1 %2 // |#hd #tl #Hind * normalize cases (a==hd) normalize /3/]
197 lemma assoc_to_mem: ∀A,B,a,l1,l2,b.
198 assoc A B a l1 l2 = Some ? b → mem ? b l2.
200 [#l2 #b normalize #H destruct
202 [#b normalize #H destruct
203 |#hd2 #tl2 #b normalize cases (a==hd1) normalize
204 [#H %1 destruct //|#H %2 @Hind @H]
209 inductive red (O:Type[0]) (D:O→FinSet) : T O D →T O D → Prop ≝
210 | (* we only allow beta on closed arguments *)
211 rbeta: ∀P,M,N. is_closed O D 0 N →
212 red O D (App O D (Lambda O D P M) N) (subst O D M 0 N)
214 assoc (FinSet_of_FType O D ty) ? a (enum (FinSet_of_FType O D ty)) v = Some ? M →
215 red O D (App O D (Vec O D ty v) (to_T O D ty a)) M
216 | rappl: ∀M,M1,N. red O D M M1 → red O D (App O D M N) (App O D M1 N)
217 | rappr: ∀M,N,N1. red O D N N1 → red O D (App O D M N) (App O D M N1)
218 | rlam: ∀ty,N,N1. red O D N N1 → red O D (Lambda O D ty N) (Lambda O D ty N1)
219 | rmem: ∀ty,M. red O D (Lambda O D ty M)
220 (Vec O D ty (map ?? (λa. subst O D M 0 (to_T O D ty a))
221 (enum (FinSet_of_FType O D ty))))
222 | rvec: ∀ty,N,N1,v,v1. red O D N N1 →
223 red O D (Vec O D ty (v@N::v1)) (Vec O D ty (v@N1::v1)).
225 (* some inversion cases *)
226 lemma red_vec: ∀O,D,ty,v,M.
227 red O D (Vec O D ty v) M → ∃N,N1,v1,v2.
228 red O D N N1 ∧ v = v1@N::v2 ∧ M = Vec O D ty (v1@N1::v2).
229 #O #D #ty #v #M #Hred inversion Hred
230 [#ty1 #M0 #N #Hc #H destruct
231 |#ty1 #v1 #a #M0 #_ #H destruct
232 |#M0 #M1 #N #_ #_ #H destruct
233 |#M0 #M1 #N #_ #_ #H destruct
234 |#ty1 #M #M1 #_ #_ #H destruct
235 |#ty1 #M0 #H destruct
236 |#ty1 #N #N1 #v1 #v2 #Hred1 #_ #H destruct #_ %{N} %{N1} %{v1} %{v2} /3/
240 lemma red_lambda: ∀O,D,ty,M,N.
241 red O D (Lambda O D ty M) N →
242 (∃M1. red O D M M1 ∧ N = (Lambda O D ty M1)) ∨
243 N = Vec O D ty (map ?? (λa. subst O D M 0 (to_T O D ty a))
244 (enum (FinSet_of_FType O D ty))).
245 #O #D #ty #M #N #Hred inversion Hred
246 [#ty1 #M0 #N #Hc #H destruct
247 |#ty1 #v1 #a #M0 #_ #H destruct
248 |#M0 #M1 #N #_ #_ #H destruct
249 |#M0 #M1 #N #_ #_ #H destruct
250 |#ty1 #P #P1 #redP #_ #H #H1 destruct %1 %{P1} % //
251 |#ty1 #M0 #H destruct #_ %2 //
252 |#ty1 #N #N1 #v1 #v2 #Hred1 #_ #H destruct
256 lemma red_val: ∀O,D,ty,a,N.
257 red O D (Val O D ty a) N → False.
258 #O #D #ty #M #N #Hred inversion Hred
259 [#ty1 #M0 #N #Hc #H destruct
260 |#ty1 #v1 #a #M0 #_ #H destruct
261 |#M0 #M1 #N #_ #_ #H destruct
262 |#M0 #M1 #N #_ #_ #H destruct
263 |#ty1 #N1 #N2 #_ #_ #H destruct
264 |#ty1 #M0 #H destruct #_
265 |#ty1 #N #N1 #v1 #v2 #Hred1 #_ #H destruct
269 lemma red_rel: ∀O,D,n,N.
270 red O D (Rel O D n) N → False.
271 #O #D #n #N #Hred inversion Hred
272 [#ty1 #M0 #N #Hc #H destruct
273 |#ty1 #v1 #a #M0 #_ #H destruct
274 |#M0 #M1 #N #_ #_ #H destruct
275 |#M0 #M1 #N #_ #_ #H destruct
276 |#ty1 #N1 #N2 #_ #_ #H destruct
277 |#ty1 #M0 #H destruct #_
278 |#ty1 #N #N1 #v1 #v2 #Hred1 #_ #H destruct
282 lemma star_red_appl: ∀O,D,M,M1,N. star ? (red O D) M M1 →
283 star ? (red O D) (App O D M N) (App O D M1 N).
284 #O #D #M #N #N1 #H elim H //
285 #P #Q #Hind #HPQ #Happ %1[|@Happ] @rappl @HPQ
288 lemma star_red_appr: ∀O,D,M,N,N1. star ? (red O D) N N1 →
289 star ? (red O D) (App O D M N) (App O D M N1).
290 #O #D #M #N #N1 #H elim H //
291 #P #Q #Hind #HPQ #Happ %1[|@Happ] @rappr @HPQ
294 lemma star_red_vec: ∀O,D,ty,N,N1,v1,v2. star ? (red O D) N N1 →
295 star ? (red O D) (Vec O D ty (v1@N::v2)) (Vec O D ty (v1@N1::v2)).
296 #O #D #ty #N #N1 #v1 #v2 #H elim H //
297 #P #Q #Hind #HPQ #Hvec %1[|@Hvec] @rvec @HPQ
300 lemma star_red_vec1: ∀O,D,ty,v1,v2,v. |v1| = |v2| →
301 (∀n,M. star ? (red O D) (nth n ? v1 M) (nth n ? v2 M)) →
302 star ? (red O D) (Vec O D ty (v@v1)) (Vec O D ty (v@v2)).
303 #O #D #ty #v1 elim v1
304 [#v2 #v normalize #Hv2 >(lenght_to_nil … (sym_eq … Hv2)) normalize //
305 |#N1 #tl1 #Hind * [normalize #v #H destruct] #N2 #tl2 #v normalize #HS
306 #H @(trans_star … (Vec O D ty (v@N2::tl1)))
307 [@star_red_vec @(H 0 N1)
308 |>append_cons >(append_cons ??? tl2) @(Hind… (injective_S … HS))
314 lemma star_red_vec2: ∀O,D,ty,v1,v2. |v1| = |v2| →
315 (∀n,M. star ? (red O D) (nth n ? v1 M) (nth n ? v2 M)) →
316 star ? (red O D) (Vec O D ty v1) (Vec O D ty v2).
317 #O #D #ty #v1 #v2 @(star_red_vec1 … [ ])
320 lemma star_red_lambda: ∀O,D,ty,N,N1. star ? (red O D) N N1 →
321 star ? (red O D) (Lambda O D ty N) (Lambda O D ty N1).
322 #O #D #ty #N #N1 #H elim H //
323 #P #Q #Hind #HPQ #Hlam %1[|@Hlam] @rlam @HPQ
326 axiom red_subst : ∀O,D,M,N,N1,i.
327 red O D N N1 → red O D (subst O D M i N) (subst O D M i N1).
329 axiom red_star_subst : ∀O,D,M,N,N1,i.
330 star ? (red O D) N N1 → star ? (red O D) (subst O D M i N) (subst O D M i N1).
332 axiom red_star_subst2 : ∀O,D,M,M1,N,i.
333 star ? (red O D) M M1 → star ? (red O D) (subst O D M i N) (subst O D M1 i N).
335 axiom canonical_to_T: ∀O,D.∀M:T O D.∀ty.(* type_of M ty → *)
336 ∃a:FinSet_of_FType O D ty. star ? (red O D) M (to_T O D ty a).
338 axiom normal_to_T: ∀O,D,M,ty,a. red O D (to_T O D ty a) M → False.
340 axiom red_closed: ∀O,D,M,M1.
341 is_closed O D 0 M → red O D M M1 → is_closed O D 0 M1.
343 lemma critical: ∀O,D,ty,M,N.
345 .star (T O D) (red O D) (subst O D M 0 N) M3
346 ∧star (T O D) (red O D)
349 (map (FinSet_of_FType O D ty) (T O D)
350 (λa0:FinSet_of_FType O D ty.subst O D M 0 (to_T O D ty a0))
351 (enum (FinSet_of_FType O D ty)))) N) M3.
353 lapply (canonical_to_T O D N ty) * #a #Ha
354 %{(subst O D M 0 (to_T O D ty a))} (* CR-term *)
355 %[@red_star_subst @Ha
356 |@trans_star [|@(star_red_appr … Ha)] @R_to_star @riota
357 lapply (enum_complete (FinSet_of_FType O D ty) a)
358 elim (enum (FinSet_of_FType O D ty))
359 [normalize #H1 destruct (H1)
360 |#hd #tl #Hind #H cases (orb_true_l … H) -H #Hcase
361 [normalize >Hcase >(\P Hcase) //
362 |normalize cases (true_or_false (a==hd)) #Hcase1
363 [normalize >Hcase1 >(\P Hcase1) // |>Hcase1 @Hind @Hcase]
369 lemma critical2: ∀O,D,ty,a,M,M1,M2,v.
370 red O D (Vec O D ty v) M →
371 red O D (App O D (Vec O D ty v) (to_T O D ty a)) M1 →
372 assoc (FinSet_of_FType O D ty) (T O D) a (enum (FinSet_of_FType O D ty)) v
375 .star (T O D) (red O D) M2 M3
376 ∧star (T O D) (red O D) (App O D M (to_T O D ty a)) M3.
377 #O #D #ty #a #M #M1 #M2 #v #redM #redM1 #Ha lapply (red_vec … redM) -redM
378 * #N * #N1 * #v1 * #v2 * * #Hred1 #Hv #HM0 >HM0 -HM0 >Hv in Ha; #Ha
379 cases (same_assoc … a (enum (FinSet_of_FType O D ty)) v1 v2 N N1)
380 [* >Ha -Ha #H1 destruct (H1) #Ha
381 %{N1} (* CR-term *) % [@R_to_star //|@R_to_star @(riota … Ha)]
382 |#Ha1 %{M2} (* CR-term *) % [// | @R_to_star @riota <Ha1 @Ha]
386 lemma nth_to_default: ∀A,l,n,d.
387 |l| ≤ n → nth n A l d = d.
388 #A #l elim l [//] #a #tl #Hind #n cases n
389 [#d normalize #H @False_ind @(absurd … H) @lt_to_not_le //
390 |#m #d normalize #H @Hind @le_S_S_to_le @H
394 lemma nth_map: ∀A,B,l,f,n,d1,d2.
395 n < |l| → nth n B (map … f l) d1 = f (nth n A l d2).
397 [#m #d1 #d2 normalize #H @False_ind @(absurd … H) @lt_to_not_le //
398 |#a #tl #Hind #m #d1 #d2 cases m normalize //
399 #m1 #H @Hind @le_S_S_to_le @H
403 lemma critical3: ∀O,D,ty,M1,M2. red O D M1 M2 →
404 ∃M3:T O D.star (T O D) (red O D) (Lambda O D ty M2) M3
405 ∧star (T O D) (red O D)
407 (map (FinSet_of_FType O D ty) (T O D)
408 (λa:FinSet_of_FType O D ty.subst O D M1 0 (to_T O D ty a))
409 (enum (FinSet_of_FType O D ty)))) M3.
410 #O #D #ty #M1 #M2 #Hred
412 (map (FinSet_of_FType O D ty) (T O D)
413 (λa:FinSet_of_FType O D ty.subst O D M2 0 (to_T O D ty a))
414 (enum (FinSet_of_FType O D ty))))} (* CR-term *) %
416 |@star_red_vec2 [>length_map >length_map //] #n #M0
417 cases (true_or_false (leb (|enum (FinSet_of_FType O D ty)|) n)) #Hcase
418 [>nth_to_default [2:>length_map @(leb_true_to_le … Hcase)]
419 >nth_to_default [2:>length_map @(leb_true_to_le … Hcase)] //
420 |cut (n < |enum (FinSet_of_FType O D ty)|)
421 [@not_le_to_lt @leb_false_to_not_le @Hcase] #Hlt
422 cut (∃a:FinSet_of_FType O D ty.True)
423 [lapply Hlt lapply (enum_complete (FinSet_of_FType O D ty))
424 cases (enum (FinSet_of_FType O D ty))
425 [#_ normalize #H @False_ind @(absurd … H) @lt_to_not_le //
429 >(nth_map ?????? a Hlt) >(nth_map ?????? a Hlt)
430 @red_star_subst2 @R_to_star //
435 (* we need to proceed by structural induction on the term and then
436 by inversion on the two redexes. The problem are the moves in a
437 same subterm, since we need an induction hypothesis, there *)
439 lemma local_confluence: ∀O,D,M,M1,M2. red O D M M1 → red O D M M2 →
440 ∃M3. star ? (red O D) M1 M3 ∧ star ? (red O D) M2 M3.
441 #O #D #M @(T_elim … M)
442 [#o #a #M1 #M2 #H elim(red_val ????? H)
443 |#n #M1 #M2 #H elim(red_rel ???? H)
444 |(* app : this is the interesting case *)
446 #M1 #M2 #H1 inversion H1 -H1
447 [(* right redex is beta *)
448 #ty #Q #N #Hc #HM >HM -HM #HM1 >HM1 - HM1 #Hl inversion Hl
449 [#ty1 #Q1 #N1 #Hc1 #H1 destruct (H1) #H_
450 %{(subst O D Q1 0 N1)} (* CR-term *) /2/
451 |#ty #v #a #M0 #_ #H1 destruct (H1) (* vacuous *)
452 |#M0 #M10 #N0 #redM0 #_ #H1 destruct (H1) #_ cases (red_lambda … redM0)
453 [* #Q1 * #redQ #HM10 >HM10
454 %{(subst O D Q1 0 N0)} (* CR-term *) %
455 [@red_star_subst2 @R_to_star //|@R_to_star @rbeta @Hc]
458 |#M0 #N0 #N1 #redN0N1 #_ #H1 destruct (H1) #HM2
459 %{(subst O D Q 0 N1)} (* CR-term *)
460 %[@red_star_subst @R_to_star //|@R_to_star @rbeta @(red_closed … Hc) //]
461 |#ty1 #N0 #N1 #_ #_ #H1 destruct (H1) (* vacuous *)
462 |#ty1 #M0 #H1 destruct (H1) (* vacuous *)
463 |#ty1 #N0 #N1 #v #v1 #_ #_ #H1 destruct (H1) (* vacuous *)
465 |(* right redex is iota *)#ty #v #a #M3 #Ha #_ #_ #Hl inversion Hl
466 [#P1 #M1 #N1 #_ #H1 destruct (H1) (* vacuous *)
467 |#ty1 #v1 #a1 #M4 #Ha1 #H1 destruct (H1) -H1 #HM4 >(inj_to_T … e0) in Ha;
468 >Ha1 #H1 destruct (H1) %{M3} (* CR-term *) /2/
469 |#M0 #M10 #N0 #redM0 #_ #H1 destruct (H1) #HM2 @(critical2 … redM0 Hl Ha)
470 |#M0 #N0 #N1 #redN0N1 #_ #H1 destruct (H1) elim (normal_to_T … redN0N1)
471 |#ty1 #N0 #N1 #_ #_ #H1 destruct (H1) (* vacuous *)
472 |#ty1 #M0 #H1 destruct (H1) (* vacuous *)
473 |#ty1 #N0 #N1 #v #v1 #_ #_ #H1 destruct (H1) (* vacuous *)
475 |(* right redex is appl *)#M3 #M4 #N #redM3M4 #_ #H1 destruct (H1) #_
477 [#ty1 #M1 #N1 #Hc #H1 destruct (H1) #HM2 lapply (red_lambda … redM3M4) *
478 [* #M3 * #H1 #H2 >H2 %{(subst O D M3 0 N1)} %
479 [@R_to_star @rbeta @Hc|@red_star_subst2 @R_to_star @H1]
480 |#H >H -H lapply (critical O D ty1 M1 N1) * #M3 * #H1 #H2
483 |#ty1 #v1 #a1 #M4 #Ha1 #H1 #H2 destruct
484 lapply (critical2 … redM3M4 Hl Ha1) * #M3 * #H1 #H2 %{M3} /2/
485 |#M0 #M10 #N0 #redM0 #_ #H1 destruct (H1) #HM2
486 lapply (HindP … redM0 redM3M4) * #M3 * #H1 #H2
487 %{(App O D M3 N0)} (* CR-term *) % [@star_red_appl //|@star_red_appl //]
488 |#M0 #N0 #N1 #redN0N1 #_ #H1 destruct (H1) #_
489 %{(App O D M4 N1)} % @R_to_star [@rappr //|@rappl //]
490 |#ty1 #N0 #N1 #_ #_ #H1 destruct (H1) (* vacuous *)
491 |#ty1 #M0 #H1 destruct (H1) (* vacuous *)
492 |#ty1 #N0 #N1 #v #v1 #_ #_ #H1 destruct (H1) (* vacuous *)
494 |(* right redex is appr *)#M3 #N #N1 #redN #_ #H1 destruct (H1) #_
496 [#ty1 #M0 #N0 #Hc #H1 destruct (H1) #HM2
497 %{(subst O D M0 0 N1)} (* CR-term *) %
498 [@R_to_star @rbeta @(red_closed … Hc) //|@red_star_subst @R_to_star // ]
499 |#ty1 #v1 #a1 #M4 #Ha1 #H1 #H2 destruct (H1) elim (normal_to_T … redN)
500 |#M0 #M10 #N0 #redM0 #_ #H1 destruct (H1) #HM2
501 %{(App O D M10 N1)} (* CR-term *) % @R_to_star [@rappl //|@rappr //]
502 |#M0 #N0 #N10 #redN0 #_ #H1 destruct (H1) #_
503 lapply (HindQ … redN0 redN) * #M3 * #H1 #H2
504 %{(App O D M0 M3)} (* CR-term *) % [@star_red_appr //|@star_red_appr //]
505 |#ty1 #N0 #N1 #_ #_ #H1 destruct (H1) (* vacuous *)
506 |#ty1 #M0 #H1 destruct (H1) (* vacuous *)
507 |#ty1 #N0 #N1 #v #v1 #_ #_ #H1 destruct (H1) (* vacuous *)
509 |(* right redex is rlam *) #ty #N0 #N1 #_ #_ #H1 destruct (H1) (* vacuous *)
510 |(* right redex is rmem *) #ty #M0 #H1 destruct (H1) (* vacuous *)
511 |(* right redex is vec *) #ty #N #N1 #v #v1 #_ #_
512 #H1 destruct (H1) (* vacuous *)
514 |#ty #M1 #Hind #M2 #M3 #H1 #H2 (* this case is not trivial any more *)
515 lapply (red_lambda … H1) *
516 [* #M4 * #H3 #H4 >H4 lapply (red_lambda … H2) *
517 [* #M5 * #H5 #H6 >H6 lapply(Hind … H3 H5) * #M6 * #H7 #H8
518 %{(Lambda O D ty M6)} (* CR-term *) % @star_red_lambda //
519 |#H5 >H5 @critical3 //
521 |#HM2 >HM2 lapply (red_lambda … H2) *
522 [* #M4 * #Hred #HM3 >HM3 lapply (critical3 … ty ?? Hred) * #M5
523 * #H3 #H4 %{M5} (* CR-term *) % //
524 |#HM3 >HM3 %{M3} (* CR-term *) % //
527 |#ty #v1 #Hind #M1 #M2 #H1 #H2
528 lapply (red_vec … H1) * #N11 * #N12 * #v11 * #v12 * * #redN11 #Hv1 #HM1
529 lapply (red_vec … H2) * #N21* #N22 * #v21 * #v22 * * #redN21 #Hv2 #HM2
530 >Hv1 in Hv2; #Hvv lapply (compare_append … Hvv) -Hvv *
531 (* we must proceed by cases on the list *) * normalize
533 [>append_nil * #Hl1 #Hl2 destruct lapply(Hind N11 … redN11 redN21)
534 [@mem_append_l2 %1 //]
536 %{(Vec O D ty (v21@M3::v12))} (* CR-term *)
537 % [@star_red_vec //|@star_red_vec //]
538 |>append_nil * #Hl1 #Hl2 destruct lapply(Hind N21 … redN21 redN11)
539 [@mem_append_l2 %1 //]
541 %{(Vec O D ty (v11@M3::v22))} (* CR-term *)
542 % [@star_red_vec //|@star_red_vec //]
544 |(* N11 ≠ N21 *) -Hind #P #l *
545 [* #Hv11 #Hv22 destruct
546 %{((Vec O D ty ((v21@N22::l)@N12::v12)))} (* CR-term *) % @R_to_star
547 [>associative_append >associative_append normalize @rvec //
548 |>append_cons <associative_append <append_cons in ⊢ (???%?); @rvec //
550 |* #Hv11 #Hv22 destruct
551 %{((Vec O D ty ((v11@N12::l)@N22::v22)))} (* CR-term *) % @R_to_star
552 [>append_cons <associative_append <append_cons in ⊢ (???%?); @rvec //
553 |>associative_append >associative_append normalize @rvec //