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15 include "ground_2/notation/relations/rcoafter_3.ma".
16 include "ground_2/relocation/rtmap_sor.ma".
17 include "ground_2/relocation/rtmap_after.ma".
19 (* RELOCATION MAP ***********************************************************)
21 coinductive coafter: relation3 rtmap rtmap rtmap ≝
22 | coafter_refl: ∀f1,f2,f,g1,g2,g. coafter f1 f2 f →
23 ↑f1 = g1 → ↑f2 = g2 → ↑f = g → coafter g1 g2 g
24 | coafter_push: ∀f1,f2,f,g1,g2,g. coafter f1 f2 f →
25 ↑f1 = g1 → ⫯f2 = g2 → ⫯f = g → coafter g1 g2 g
26 | coafter_next: ∀f1,f2,f,g1,g. coafter f1 f2 f →
27 ⫯f1 = g1 → ↑f = g → coafter g1 f2 g
30 interpretation "relational co-composition (rtmap)"
31 'RCoAfter f1 f2 f = (coafter f1 f2 f).
33 definition H_coafter_inj: predicate rtmap ≝
35 ∀f,f21,f22. f1 ~⊚ f21 ≡ f → f1 ~⊚ f22 ≡ f → f21 ≗ f22.
37 definition H_coafter_fwd_isid2: predicate rtmap ≝
38 λf1. ∀f2,f. f1 ~⊚ f2 ≡ f → 𝐓⦃f1⦄ → 𝐈⦃f⦄ → 𝐈⦃f2⦄.
40 definition H_coafter_isfin2_fwd: predicate rtmap ≝
41 λf1. ∀f2. 𝐅⦃f2⦄ → 𝐓⦃f1⦄ → ∀f. f1 ~⊚ f2 ≡ f → 𝐅⦃f⦄.
43 (* Basic inversion lemmas ***************************************************)
45 lemma coafter_inv_ppx: ∀g1,g2,g. g1 ~⊚ g2 ≡ g → ∀f1,f2. ↑f1 = g1 → ↑f2 = g2 →
46 ∃∃f. f1 ~⊚ f2 ≡ f & ↑f = g.
47 #g1 #g2 #g * -g1 -g2 -g #f1 #f2 #f #g1
48 [ #g2 #g #Hf #H1 #H2 #H #x1 #x2 #Hx1 #Hx2 destruct
49 >(injective_push … Hx1) >(injective_push … Hx2) -x2 -x1
50 /2 width=3 by ex2_intro/
51 | #g2 #g #_ #_ #H2 #_ #x1 #x2 #_ #Hx2 destruct
52 elim (discr_push_next … Hx2)
53 | #g #_ #H1 #_ #x1 #x2 #Hx1 #_ destruct
54 elim (discr_push_next … Hx1)
58 lemma coafter_inv_pnx: ∀g1,g2,g. g1 ~⊚ g2 ≡ g → ∀f1,f2. ↑f1 = g1 → ⫯f2 = g2 →
59 ∃∃f. f1 ~⊚ f2 ≡ f & ⫯f = g.
60 #g1 #g2 #g * -g1 -g2 -g #f1 #f2 #f #g1
61 [ #g2 #g #_ #_ #H2 #_ #x1 #x2 #_ #Hx2 destruct
62 elim (discr_next_push … Hx2)
63 | #g2 #g #Hf #H1 #H2 #H3 #x1 #x2 #Hx1 #Hx2 destruct
64 >(injective_push … Hx1) >(injective_next … Hx2) -x2 -x1
65 /2 width=3 by ex2_intro/
66 | #g #_ #H1 #_ #x1 #x2 #Hx1 #_ destruct
67 elim (discr_push_next … Hx1)
71 lemma coafter_inv_nxx: ∀g1,f2,g. g1 ~⊚ f2 ≡ g → ∀f1. ⫯f1 = g1 →
72 ∃∃f. f1 ~⊚ f2 ≡ f & ↑f = g.
73 #g1 #f2 #g * -g1 -f2 -g #f1 #f2 #f #g1
74 [ #g2 #g #_ #H1 #_ #_ #x1 #Hx1 destruct
75 elim (discr_next_push … Hx1)
76 | #g2 #g #_ #H1 #_ #_ #x1 #Hx1 destruct
77 elim (discr_next_push … Hx1)
78 | #g #Hf #H1 #H #x1 #Hx1 destruct
79 >(injective_next … Hx1) -x1
80 /2 width=3 by ex2_intro/
84 (* Advanced inversion lemmas ************************************************)
86 lemma coafter_inv_ppp: ∀g1,g2,g. g1 ~⊚ g2 ≡ g →
87 ∀f1,f2,f. ↑f1 = g1 → ↑f2 = g2 → ↑f = g → f1 ~⊚ f2 ≡ f.
88 #g1 #g2 #g #Hg #f1 #f2 #f #H1 #H2 #H
89 elim (coafter_inv_ppx … Hg … H1 H2) -g1 -g2 #x #Hf #Hx destruct
90 <(injective_push … Hx) -f //
93 lemma coafter_inv_ppn: ∀g1,g2,g. g1 ~⊚ g2 ≡ g →
94 ∀f1,f2,f. ↑f1 = g1 → ↑f2 = g2 → ⫯f = g → ⊥.
95 #g1 #g2 #g #Hg #f1 #f2 #f #H1 #H2 #H
96 elim (coafter_inv_ppx … Hg … H1 H2) -g1 -g2 #x #Hf #Hx destruct
97 elim (discr_push_next … Hx)
100 lemma coafter_inv_pnn: ∀g1,g2,g. g1 ~⊚ g2 ≡ g →
101 ∀f1,f2,f. ↑f1 = g1 → ⫯f2 = g2 → ⫯f = g → f1 ~⊚ f2 ≡ f.
102 #g1 #g2 #g #Hg #f1 #f2 #f #H1 #H2 #H
103 elim (coafter_inv_pnx … Hg … H1 H2) -g1 -g2 #x #Hf #Hx destruct
104 <(injective_next … Hx) -f //
107 lemma coafter_inv_pnp: ∀g1,g2,g. g1 ~⊚ g2 ≡ g →
108 ∀f1,f2,f. ↑f1 = g1 → ⫯f2 = g2 → ↑f = g → ⊥.
109 #g1 #g2 #g #Hg #f1 #f2 #f #H1 #H2 #H
110 elim (coafter_inv_pnx … Hg … H1 H2) -g1 -g2 #x #Hf #Hx destruct
111 elim (discr_next_push … Hx)
114 lemma coafter_inv_nxp: ∀g1,f2,g. g1 ~⊚ f2 ≡ g →
115 ∀f1,f. ⫯f1 = g1 → ↑f = g → f1 ~⊚ f2 ≡ f.
116 #g1 #f2 #g #Hg #f1 #f #H1 #H
117 elim (coafter_inv_nxx … Hg … H1) -g1 #x #Hf #Hx destruct
118 <(injective_push … Hx) -f //
121 lemma coafter_inv_nxn: ∀g1,f2,g. g1 ~⊚ f2 ≡ g →
122 ∀f1,f. ⫯f1 = g1 → ⫯f = g → ⊥.
123 #g1 #f2 #g #Hg #f1 #f #H1 #H
124 elim (coafter_inv_nxx … Hg … H1) -g1 #x #Hf #Hx destruct
125 elim (discr_push_next … Hx)
128 lemma coafter_inv_pxp: ∀g1,g2,g. g1 ~⊚ g2 ≡ g →
129 ∀f1,f. ↑f1 = g1 → ↑f = g →
130 ∃∃f2. f1 ~⊚ f2 ≡ f & ↑f2 = g2.
131 #g1 #g2 #g #Hg #f1 #f #H1 #H elim (pn_split g2) * #f2 #H2
132 [ lapply (coafter_inv_ppp … Hg … H1 H2 H) -g1 -g /2 width=3 by ex2_intro/
133 | elim (coafter_inv_pnp … Hg … H1 H2 H)
137 lemma coafter_inv_pxn: ∀g1,g2,g. g1 ~⊚ g2 ≡ g →
138 ∀f1,f. ↑f1 = g1 → ⫯f = g →
139 ∃∃f2. f1 ~⊚ f2 ≡ f & ⫯f2 = g2.
140 #g1 #g2 #g #Hg #f1 #f #H1 #H elim (pn_split g2) * #f2 #H2
141 [ elim (coafter_inv_ppn … Hg … H1 H2 H)
142 | lapply (coafter_inv_pnn … Hg … H1 … H) -g1 -g /2 width=3 by ex2_intro/
146 lemma coafter_inv_xxn: ∀g1,g2,g. g1 ~⊚ g2 ≡ g → ∀f. ⫯f = g →
147 ∃∃f1,f2. f1 ~⊚ f2 ≡ f & ↑f1 = g1 & ⫯f2 = g2.
148 #g1 #g2 #g #Hg #f #H elim (pn_split g1) * #f1 #H1
149 [ elim (coafter_inv_pxn … Hg … H1 H) -g /2 width=5 by ex3_2_intro/
150 | elim (coafter_inv_nxn … Hg … H1 H)
154 lemma coafter_inv_xnn: ∀g1,g2,g. g1 ~⊚ g2 ≡ g →
155 ∀f2,f. ⫯f2 = g2 → ⫯f = g →
156 ∃∃f1. f1 ~⊚ f2 ≡ f & ↑f1 = g1.
157 #g1 #g2 #g #Hg #f2 #f #H2 destruct #H
158 elim (coafter_inv_xxn … Hg … H) -g
159 #z1 #z2 #Hf #H1 #H2 destruct /2 width=3 by ex2_intro/
162 lemma coafter_inv_xxp: ∀g1,g2,g. g1 ~⊚ g2 ≡ g → ∀f. ↑f = g →
163 (∃∃f1,f2. f1 ~⊚ f2 ≡ f & ↑f1 = g1 & ↑f2 = g2) ∨
164 ∃∃f1. f1 ~⊚ g2 ≡ f & ⫯f1 = g1.
165 #g1 #g2 #g #Hg #f #H elim (pn_split g1) * #f1 #H1
166 [ elim (coafter_inv_pxp … Hg … H1 H) -g
167 /3 width=5 by or_introl, ex3_2_intro/
168 | /4 width=5 by coafter_inv_nxp, or_intror, ex2_intro/
172 lemma coafter_inv_pxx: ∀g1,g2,g. g1 ~⊚ g2 ≡ g → ∀f1. ↑f1 = g1 →
173 (∃∃f2,f. f1 ~⊚ f2 ≡ f & ↑f2 = g2 & ↑f = g) ∨
174 (∃∃f2,f. f1 ~⊚ f2 ≡ f & ⫯f2 = g2 & ⫯f = g).
175 #g1 #g2 #g #Hg #f1 #H1 elim (pn_split g2) * #f2 #H2
176 [ elim (coafter_inv_ppx … Hg … H1 H2) -g1
177 /3 width=5 by or_introl, ex3_2_intro/
178 | elim (coafter_inv_pnx … Hg … H1 H2) -g1
179 /3 width=5 by or_intror, ex3_2_intro/
183 (* Basic properties *********************************************************)
185 corec lemma coafter_eq_repl_back2: ∀f1,f. eq_repl_back (λf2. f2 ~⊚ f1 ≡ f).
186 #f1 #f #f2 * -f2 -f1 -f
187 #f21 #f1 #f #g21 [1,2: #g1 ] #g #Hf #H21 [1,2: #H1 ] #H #g22 #H0
188 [ cases (eq_inv_px … H0 … H21) -g21 /3 width=7 by coafter_refl/
189 | cases (eq_inv_px … H0 … H21) -g21 /3 width=7 by coafter_push/
190 | cases (eq_inv_nx … H0 … H21) -g21 /3 width=5 by coafter_next/
194 lemma coafter_eq_repl_fwd2: ∀f1,f. eq_repl_fwd (λf2. f2 ~⊚ f1 ≡ f).
195 #f1 #f @eq_repl_sym /2 width=3 by coafter_eq_repl_back2/
198 corec lemma coafter_eq_repl_back1: ∀f2,f. eq_repl_back (λf1. f2 ~⊚ f1 ≡ f).
199 #f2 #f #f1 * -f2 -f1 -f
200 #f2 #f11 #f #g2 [1,2: #g11 ] #g #Hf #H2 [1,2: #H11 ] #H #g2 #H0
201 [ cases (eq_inv_px … H0 … H11) -g11 /3 width=7 by coafter_refl/
202 | cases (eq_inv_nx … H0 … H11) -g11 /3 width=7 by coafter_push/
203 | @(coafter_next … H2 H) /2 width=5 by/
207 lemma coafter_eq_repl_fwd1: ∀f2,f. eq_repl_fwd (λf1. f2 ~⊚ f1 ≡ f).
208 #f2 #f @eq_repl_sym /2 width=3 by coafter_eq_repl_back1/
211 corec lemma coafter_eq_repl_back0: ∀f1,f2. eq_repl_back (λf. f2 ~⊚ f1 ≡ f).
212 #f2 #f1 #f * -f2 -f1 -f
213 #f2 #f1 #f01 #g2 [1,2: #g1 ] #g01 #Hf01 #H2 [1,2: #H1 ] #H01 #g02 #H0
214 [ cases (eq_inv_px … H0 … H01) -g01 /3 width=7 by coafter_refl/
215 | cases (eq_inv_nx … H0 … H01) -g01 /3 width=7 by coafter_push/
216 | cases (eq_inv_px … H0 … H01) -g01 /3 width=5 by coafter_next/
220 lemma coafter_eq_repl_fwd0: ∀f2,f1. eq_repl_fwd (λf. f2 ~⊚ f1 ≡ f).
221 #f2 #f1 @eq_repl_sym /2 width=3 by coafter_eq_repl_back0/
224 (* Main inversion lemmas ****************************************************)
226 corec theorem coafter_mono: ∀f1,f2,x,y. f1 ~⊚ f2 ≡ x → f1 ~⊚ f2 ≡ y → x ≗ y.
227 #f1 #f2 #x #y * -f1 -f2 -x
228 #f1 #f2 #x #g1 [1,2: #g2 ] #g #Hx #H1 [1,2: #H2 ] #H0x #Hy
229 [ cases (coafter_inv_ppx … Hy … H1 H2) -g1 -g2 /3 width=8 by eq_push/
230 | cases (coafter_inv_pnx … Hy … H1 H2) -g1 -g2 /3 width=8 by eq_next/
231 | cases (coafter_inv_nxx … Hy … H1) -g1 /3 width=8 by eq_push/
235 lemma coafter_mono_eq: ∀f1,f2,f. f1 ~⊚ f2 ≡ f → ∀g1,g2,g. g1 ~⊚ g2 ≡ g →
236 f1 ≗ g1 → f2 ≗ g2 → f ≗ g.
237 /4 width=4 by coafter_mono, coafter_eq_repl_back1, coafter_eq_repl_back2/ qed-.
239 (* Inversion lemmas with pushs **********************************************)
241 lemma coafter_fwd_pushs: ∀n,g2,g1,g. g2 ~⊚ g1 ≡ g → @⦃0, g2⦄ ≡ n →
243 #n elim n -n /2 width=2 by ex_intro/
244 #n #IH #g2 #g1 #g #Hg #Hg2
245 cases (at_inv_pxn … Hg2) -Hg2 [ |*: // ] #f2 #Hf2 #H2
246 cases (coafter_inv_nxx … Hg … H2) -Hg -H2 #f #Hf #H0 destruct
247 elim (IH … Hf Hf2) -g1 -g2 -f2 /2 width=2 by ex_intro/
250 (* Inversion lemmas with tail ***********************************************)
252 lemma coafter_inv_tl1: ∀g2,g1,g. g2 ~⊚ ⫱g1 ≡ g →
253 ∃∃f. ↑g2 ~⊚ g1 ≡ f & ⫱f = g.
254 #g2 #g1 #g elim (pn_split g1) * #f1 #H1 #H destruct
255 [ /3 width=7 by coafter_refl, ex2_intro/
256 | @(ex2_intro … (⫯g)) /2 width=7 by coafter_push/ (**) (* full auto fails *)
260 lemma coafter_inv_tl0: ∀g2,g1,g. g2 ~⊚ g1 ≡ ⫱g →
261 ∃∃f1. ↑g2 ~⊚ f1 ≡ g & ⫱f1 = g1.
262 #g2 #g1 #g elim (pn_split g) * #f #H0 #H destruct
263 [ /3 width=7 by coafter_refl, ex2_intro/
264 | @(ex2_intro … (⫯g1)) /2 width=7 by coafter_push/ (**) (* full auto fails *)
268 (* Properties with iterated tail ********************************************)
270 lemma coafter_tls: ∀n,f1,f2,f. @⦃0, f1⦄ ≡ n →
271 f1 ~⊚ f2 ≡ f → ⫱*[n]f1 ~⊚ f2 ≡ ⫱*[n]f.
273 #n #IH #f1 #f2 #f #Hf1 #Hf
274 cases (at_inv_pxn … Hf1) -Hf1 [ |*: // ] #g1 #Hg1 #H1
275 cases (coafter_inv_nxx … Hf … H1) -Hf #g #Hg #H0 destruct
276 <tls_xn <tls_xn /2 width=1 by/
279 lemma coafter_tls_succ: ∀g2,g1,g. g2 ~⊚ g1 ≡ g →
280 ∀n. @⦃0, g2⦄ ≡ n → ⫱*[⫯n]g2 ~⊚ ⫱g1 ≡ ⫱*[⫯n]g.
281 #g2 #g1 #g #Hg #n #Hg2
282 lapply (coafter_tls … Hg2 … Hg) -Hg #Hg
283 lapply (at_pxx_tls … Hg2) -Hg2 #H
284 elim (at_inv_pxp … H) -H [ |*: // ] #f2 #H2
285 elim (coafter_inv_pxx … Hg … H2) -Hg * #f1 #f #Hf #H1 #H0 destruct
286 <tls_S <tls_S <H2 <H0 -g2 -g -n //
289 lemma coafter_fwd_xpx_pushs: ∀g2,f1,g,n. g2 ~⊚ ↑f1 ≡ g → @⦃0, g2⦄ ≡ n →
291 #g2 #g1 #g #n #Hg #Hg2
292 elim (coafter_fwd_pushs … Hg Hg2) #f #H0 destruct
293 lapply (coafter_tls … Hg2 Hg) -Hg <tls_pushs #Hf
294 lapply (at_pxx_tls … Hg2) -Hg2 #H
295 elim (at_inv_pxp … H) -H [ |*: // ] #f2 #H2
296 elim (coafter_inv_pxx … Hf … H2) -Hf -H2 * #f1 #g #_ #H1 #H0 destruct
297 [ /2 width=2 by ex_intro/
298 | elim (discr_next_push … H1)
302 lemma coafter_fwd_xnx_pushs: ∀g2,f1,g,n. g2 ~⊚ ⫯f1 ≡ g → @⦃0, g2⦄ ≡ n →
304 #g2 #g1 #g #n #Hg #Hg2
305 elim (coafter_fwd_pushs … Hg Hg2) #f #H0 destruct
306 lapply (coafter_tls … Hg2 Hg) -Hg <tls_pushs #Hf
307 lapply (at_pxx_tls … Hg2) -Hg2 #H
308 elim (at_inv_pxp … H) -H [ |*: // ] #f2 #H2
309 elim (coafter_inv_pxx … Hf … H2) -Hf -H2 * #f1 #g #_ #H1 #H0 destruct
310 [ elim (discr_push_next … H1)
311 | /2 width=2 by ex_intro/
315 (* Properties with test for identity ****************************************)
317 corec lemma coafter_isid_sn: ∀f1. 𝐈⦃f1⦄ → ∀f2. f1 ~⊚ f2 ≡ f2.
318 #f1 * -f1 #f1 #g1 #Hf1 #H1 #f2 cases (pn_split f2) * #g2 #H2
319 /3 width=7 by coafter_push, coafter_refl/
322 corec lemma coafter_isid_dx: ∀f2,f. 𝐈⦃f2⦄ → 𝐈⦃f⦄ → ∀f1. f1 ~⊚ f2 ≡ f.
323 #f2 #f * -f2 #f2 #g2 #Hf2 #H2 * -f #f #g #Hf #H #f1 cases (pn_split f1) * #g1 #H1
324 [ /3 width=7 by coafter_refl/
325 | @(coafter_next … H1 … H) /3 width=3 by isid_push/
329 (* Inversion lemmas with test for identity **********************************)
331 lemma coafter_isid_inv_sn: ∀f1,f2,f. f1 ~⊚ f2 ≡ f → 𝐈⦃f1⦄ → f2 ≗ f.
332 /3 width=6 by coafter_isid_sn, coafter_mono/ qed-.
334 lemma coafter_isid_inv_dx: ∀f1,f2,f. f1 ~⊚ f2 ≡ f → 𝐈⦃f2⦄ → 𝐈⦃f⦄.
335 /4 width=4 by eq_id_isid, coafter_isid_dx, coafter_mono/ qed-.
337 (* Properties with test for uniform relocations *****************************)
339 lemma coafter_isuni_isid: ∀f2. 𝐈⦃f2⦄ → ∀f1. 𝐔⦃f1⦄ → f1 ~⊚ f2 ≡ f2.
340 #f #Hf #g #H elim H -g
341 /3 width=5 by coafter_isid_sn, coafter_eq_repl_back0, coafter_next, eq_push_inv_isid/
346 lemma coafter_isid_isuni: ∀f1,f2. 𝐈⦃f2⦄ → 𝐔⦃f1⦄ → f1 ~⊚ ⫯f2 ≡ ⫯f1.
347 #f1 #f2 #Hf2 #H elim H -H
348 /5 width=7 by coafter_isid_dx, coafter_eq_repl_back2, coafter_next, coafter_push, eq_push_inv_isid/
351 lemma coafter_uni_next2: ∀f2. 𝐔⦃f2⦄ → ∀f1,f. ⫯f2 ~⊚ f1 ≡ f → f2 ~⊚ ⫯f1 ≡ f.
353 [ #f2 #Hf2 #f1 #f #Hf
354 elim (coafter_inv_nxx … Hf) -Hf [2,3: // ] #g #Hg #H0 destruct
355 /4 width=7 by coafter_isid_inv_sn, coafter_isid_sn, coafter_eq_repl_back0, eq_next/
356 | #f2 #_ #g2 #H2 #IH #f1 #f #Hf
357 elim (coafter_inv_nxx … Hf) -Hf [2,3: // ] #g #Hg #H0 destruct
358 /3 width=5 by coafter_next/
363 (* Properties with uniform relocations **************************************)
365 lemma coafter_uni_sn: ∀i,f. 𝐔❴i❵ ~⊚ f ≡ ↑*[i] f.
366 #i elim i -i /2 width=5 by coafter_isid_sn, coafter_next/
370 lemma coafter_uni: ∀n1,n2. 𝐔❴n1❵ ~⊚ 𝐔❴n2❵ ≡ 𝐔❴n1+n2❵.
372 /4 width=5 by coafter_uni_next2, coafter_isid_sn, coafter_isid_dx, coafter_next/
375 (* Forward lemmas on at *****************************************************)
377 lemma coafter_at_fwd: ∀i,i1,f. @⦃i1, f⦄ ≡ i → ∀f2,f1. f2 ~⊚ f1 ≡ f →
378 ∃∃i2. @⦃i1, f1⦄ ≡ i2 & @⦃i2, f2⦄ ≡ i.
379 #i elim i -i [2: #i #IH ] #i1 #f #Hf #f2 #f1 #Hf21
380 [ elim (at_inv_xxn … Hf) -Hf [1,3:* |*: // ]
381 [1: #g #j1 #Hg #H0 #H |2,4: #g #Hg #H ]
382 | elim (at_inv_xxp … Hf) -Hf //
385 [2: elim (coafter_inv_xxn … Hf21 … H) -f *
386 [ #g2 #g1 #Hg21 #H2 #H1 | #g2 #Hg21 #H2 ]
387 |*: elim (coafter_inv_xxp … Hf21 … H) -f
388 #g2 #g1 #Hg21 #H2 #H1
390 [4: -Hg21 |*: elim (IH … Hg … Hg21) -g -IH ]
391 /3 width=9 by at_refl, at_push, at_next, ex2_intro/
394 lemma coafter_fwd_at: ∀i,i2,i1,f1,f2. @⦃i1, f1⦄ ≡ i2 → @⦃i2, f2⦄ ≡ i →
395 ∀f. f2 ~⊚ f1 ≡ f → @⦃i1, f⦄ ≡ i.
396 #i elim i -i [2: #i #IH ] #i2 #i1 #f1 #f2 #Hf1 #Hf2 #f #Hf
397 [ elim (at_inv_xxn … Hf2) -Hf2 [1,3: * |*: // ]
398 #g2 [ #j2 ] #Hg2 [ #H22 ] #H20
399 [ elim (at_inv_xxn … Hf1 … H22) -i2 *
400 #g1 [ #j1 ] #Hg1 [ #H11 ] #H10
401 [ elim (coafter_inv_ppx … Hf … H20 H10) -f1 -f2 /3 width=7 by at_push/
402 | elim (coafter_inv_pnx … Hf … H20 H10) -f1 -f2 /3 width=6 by at_next/
404 | elim (coafter_inv_nxx … Hf … H20) -f2 /3 width=7 by at_next/
406 | elim (at_inv_xxp … Hf2) -Hf2 // #g2 #H22 #H20
407 elim (at_inv_xxp … Hf1 … H22) -i2 #g1 #H11 #H10
408 elim (coafter_inv_ppx … Hf … H20 H10) -f1 -f2 /2 width=2 by at_refl/
412 lemma coafter_fwd_at2: ∀f,i1,i. @⦃i1, f⦄ ≡ i → ∀f1,i2. @⦃i1, f1⦄ ≡ i2 →
413 ∀f2. f2 ~⊚ f1 ≡ f → @⦃i2, f2⦄ ≡ i.
414 #f #i1 #i #Hf #f1 #i2 #Hf1 #f2 #H elim (coafter_at_fwd … Hf … H) -f
415 #j1 #H #Hf2 <(at_mono … Hf1 … H) -i1 -i2 //
418 lemma coafter_fwd_at1: ∀i,i2,i1,f,f2. @⦃i1, f⦄ ≡ i → @⦃i2, f2⦄ ≡ i →
419 ∀f1. f2 ~⊚ f1 ≡ f → @⦃i1, f1⦄ ≡ i2.
420 #i elim i -i [2: #i #IH ] #i2 #i1 #f #f2 #Hf #Hf2 #f1 #Hf1
421 [ elim (at_inv_xxn … Hf) -Hf [1,3: * |*: // ]
422 #g [ #j1 ] #Hg [ #H01 ] #H00
423 elim (at_inv_xxn … Hf2) -Hf2 [1,3,5,7: * |*: // ]
424 #g2 [1,3: #j2 ] #Hg2 [1,2: #H22 ] #H20
425 [ elim (coafter_inv_pxp … Hf1 … H20 H00) -f2 -f /3 width=7 by at_push/
426 | elim (coafter_inv_pxn … Hf1 … H20 H00) -f2 -f /3 width=5 by at_next/
427 | elim (coafter_inv_nxp … Hf1 … H20 H00)
428 | /4 width=9 by coafter_inv_nxn, at_next/
430 | elim (at_inv_xxp … Hf) -Hf // #g #H01 #H00
431 elim (at_inv_xxp … Hf2) -Hf2 // #g2 #H21 #H20
432 elim (coafter_inv_pxp … Hf1 … H20 H00) -f2 -f /3 width=2 by at_refl/
436 (* Properties with at *******************************************************)
438 lemma coafter_uni_dx: ∀i2,i1,f2. @⦃i1, f2⦄ ≡ i2 →
439 ∀f. f2 ~⊚ 𝐔❴i1❵ ≡ f → 𝐔❴i2❵ ~⊚ ⫱*[i2] f2 ≡ f.
441 [ #i1 #f2 #Hf2 #f #Hf
442 elim (at_inv_xxp … Hf2) -Hf2 // #g2 #H1 #H2 destruct
443 lapply (coafter_isid_inv_dx … Hf ?) -Hf
444 /3 width=3 by coafter_isid_sn, coafter_eq_repl_back0/
445 | #i2 #IH #i1 #f2 #Hf2 #f #Hf
446 elim (at_inv_xxn … Hf2) -Hf2 [1,3: * |*: // ]
447 [ #g2 #j1 #Hg2 #H1 #H2 destruct
448 elim (coafter_inv_pnx … Hf) -Hf [ |*: // ] #g #Hg #H destruct
449 /3 width=5 by coafter_next/
450 | #g2 #Hg2 #H2 destruct
451 elim (coafter_inv_nxx … Hf) -Hf [2,3: // ] #g #Hg #H destruct
452 /3 width=5 by coafter_next/
457 lemma coafter_uni_sn: ∀i2,i1,f2. @⦃i1, f2⦄ ≡ i2 →
458 ∀f. 𝐔❴i2❵ ~⊚ ⫱*[i2] f2 ≡ f → f2 ~⊚ 𝐔❴i1❵ ≡ f.
460 [ #i1 #f2 #Hf2 #f #Hf
461 elim (at_inv_xxp … Hf2) -Hf2 // #g2 #H1 #H2 destruct
462 lapply (coafter_isid_inv_sn … Hf ?) -Hf
463 /3 width=3 by coafter_isid_dx, coafter_eq_repl_back0/
464 | #i2 #IH #i1 #f2 #Hf2 #f #Hf
465 elim (coafter_inv_nxx … Hf) -Hf [2,3: // ] #g #Hg #H destruct
466 elim (at_inv_xxn … Hf2) -Hf2 [1,3: * |*: // ]
467 [ #g2 #j1 #Hg2 #H1 #H2 destruct /3 width=7 by coafter_push/
468 | #g2 #Hg2 #H2 destruct /3 width=5 by coafter_next/
473 lemma coafter_uni_succ_dx: ∀i2,i1,f2. @⦃i1, f2⦄ ≡ i2 →
474 ∀f. f2 ~⊚ 𝐔❴⫯i1❵ ≡ f → 𝐔❴⫯i2❵ ~⊚ ⫱*[⫯i2] f2 ≡ f.
476 [ #i1 #f2 #Hf2 #f #Hf
477 elim (at_inv_xxp … Hf2) -Hf2 // #g2 #H1 #H2 destruct
478 elim (coafter_inv_pnx … Hf) -Hf [ |*: // ] #g #Hg #H
479 lapply (coafter_isid_inv_dx … Hg ?) -Hg
480 /4 width=5 by coafter_isid_sn, coafter_eq_repl_back0, coafter_next/
481 | #i2 #IH #i1 #f2 #Hf2 #f #Hf
482 elim (at_inv_xxn … Hf2) -Hf2 [1,3: * |*: // ]
483 [ #g2 #j1 #Hg2 #H1 #H2 destruct
484 elim (coafter_inv_pnx … Hf) -Hf [ |*: // ] #g #Hg #H destruct
485 /3 width=5 by coafter_next/
486 | #g2 #Hg2 #H2 destruct
487 elim (coafter_inv_nxx … Hf) -Hf [2,3: // ] #g #Hg #H destruct
488 /3 width=5 by coafter_next/
493 lemma coafter_uni_succ_sn: ∀i2,i1,f2. @⦃i1, f2⦄ ≡ i2 →
494 ∀f. 𝐔❴⫯i2❵ ~⊚ ⫱*[⫯i2] f2 ≡ f → f2 ~⊚ 𝐔❴⫯i1❵ ≡ f.
496 [ #i1 #f2 #Hf2 #f #Hf
497 elim (at_inv_xxp … Hf2) -Hf2 // #g2 #H1 #H2 destruct
498 elim (coafter_inv_nxx … Hf) -Hf [ |*: // ] #g #Hg #H destruct
499 lapply (coafter_isid_inv_sn … Hg ?) -Hg
500 /4 width=7 by coafter_isid_dx, coafter_eq_repl_back0, coafter_push/
501 | #i2 #IH #i1 #f2 #Hf2 #f #Hf
502 elim (coafter_inv_nxx … Hf) -Hf [2,3: // ] #g #Hg #H destruct
503 elim (at_inv_xxn … Hf2) -Hf2 [1,3: * |*: // ]
504 [ #g2 #j1 #Hg2 #H1 #H2 destruct <tls_xn in Hg; /3 width=7 by coafter_push/
505 | #g2 #Hg2 #H2 destruct <tls_xn in Hg; /3 width=5 by coafter_next/
510 lemma coafter_uni_one_dx: ∀f2,f. ↑f2 ~⊚ 𝐔❴⫯O❵ ≡ f → 𝐔❴⫯O❵ ~⊚ f2 ≡ f.
511 #f2 #f #H @(coafter_uni_succ_dx … (↑f2)) /2 width=3 by at_refl/
514 lemma coafter_uni_one_sn: ∀f1,f. 𝐔❴⫯O❵ ~⊚ f1 ≡ f → ↑f1 ~⊚ 𝐔❴⫯O❵ ≡ f.
515 /3 width=3 by coafter_uni_succ_sn, at_refl/ qed-.
517 (* Forward lemmas with istot ************************************************)
519 lemma coafter_istot_fwd: ∀f2,f1,f. f2 ~⊚ f1 ≡ f → 𝐓⦃f2⦄ → 𝐓⦃f1⦄ → 𝐓⦃f⦄.
520 #f2 #f1 #f #Hf #Hf2 #Hf1 #i1 elim (Hf1 i1) -Hf1
521 #i2 #Hf1 elim (Hf2 i2) -Hf2
522 /3 width=7 by coafter_fwd_at, ex_intro/
525 lemma coafter_fwd_istot_dx: ∀f2,f1,f. f2 ~⊚ f1 ≡ f → 𝐓⦃f⦄ → 𝐓⦃f1⦄.
526 #f2 #f1 #f #H #Hf #i1 elim (Hf i1) -Hf
527 #i2 #Hf elim (coafter_at_fwd … Hf … H) -f /2 width=2 by ex_intro/
530 lemma coafter_fwd_istot_sn: ∀f2,f1,f. f2 ~⊚ f1 ≡ f → 𝐓⦃f⦄ → 𝐓⦃f2⦄.
531 #f2 #f1 #f #H #Hf #i1 elim (Hf i1) -Hf
532 #i #Hf elim (coafter_at_fwd … Hf … H) -f
533 #i2 #Hf1 #Hf2 lapply (at_increasing … Hf1) -f1
534 #Hi12 elim (at_le_ex … Hf2 … Hi12) -i2 /2 width=2 by ex_intro/
537 lemma coafter_inv_istot: ∀f2,f1,f. f2 ~⊚ f1 ≡ f → 𝐓⦃f⦄ → 𝐓⦃f2⦄ ∧ 𝐓⦃f1⦄.
538 /3 width=4 by coafter_fwd_istot_sn, coafter_fwd_istot_dx, conj/ qed-.
540 lemma coafter_at1_fwd: ∀f1,i1,i2. @⦃i1, f1⦄ ≡ i2 → ∀f2. 𝐓⦃f2⦄ → ∀f. f2 ~⊚ f1 ≡ f →
541 ∃∃i. @⦃i2, f2⦄ ≡ i & @⦃i1, f⦄ ≡ i.
542 #f1 #i1 #i2 #Hf1 #f2 #Hf2 #f #Hf elim (Hf2 i2) -Hf2
543 /3 width=8 by coafter_fwd_at, ex2_intro/
546 lemma coafter_fwd_isid_sn: ∀f2,f1,f. 𝐓⦃f⦄ → f2 ~⊚ f1 ≡ f → f1 ≗ f → 𝐈⦃f2⦄.
547 #f2 #f1 #f #H #Hf elim (coafter_inv_istot … Hf H) -H
548 #Hf2 #Hf1 #H @isid_at_total // -Hf2
549 #i2 #i #Hf2 elim (Hf1 i2) -Hf1
550 #i0 #Hf1 lapply (at_increasing … Hf1)
551 #Hi20 lapply (coafter_fwd_at2 … i0 … Hf1 … Hf) -Hf
552 /3 width=7 by at_eq_repl_back, at_mono, at_id_le/
555 lemma coafter_fwd_isid_dx: ∀f2,f1,f. 𝐓⦃f⦄ → f2 ~⊚ f1 ≡ f → f2 ≗ f → 𝐈⦃f1⦄.
556 #f2 #f1 #f #H #Hf elim (coafter_inv_istot … Hf H) -H
557 #Hf2 #Hf1 #H2 @isid_at_total // -Hf1
558 #i1 #i2 #Hi12 elim (coafter_at1_fwd … Hi12 … Hf) -f1
559 /3 width=8 by at_inj, at_eq_repl_back/
562 corec fact coafter_inj_O_aux: ∀f1. @⦃0, f1⦄ ≡ 0 → H_coafter_inj f1.
563 #f1 #H1f1 #H2f1 #f #f21 #f22 #H1f #H2f
564 cases (at_inv_pxp … H1f1) -H1f1 [ |*: // ] #g1 #H1
565 lapply (istot_inv_push … H2f1 … H1) -H2f1 #H2g1
566 cases (H2g1 0) #n #Hn
567 cases (coafter_inv_pxx … H1f … H1) -H1f * #g21 #g #H1g #H21 #H
568 [ cases (coafter_inv_pxp … H2f … H1 H) -f1 -f #g22 #H2g #H22
569 @(eq_push … H21 H22) -f21 -f22
570 | cases (coafter_inv_pxn … H2f … H1 H) -f1 -f #g22 #H2g #H22
571 @(eq_next … H21 H22) -f21 -f22
573 @(coafter_inj_O_aux (⫱*[n]g1) … (⫱*[n]g)) -coafter_inj_O_aux
574 /2 width=1 by coafter_tls, istot_tls, at_pxx_tls/
577 fact coafter_inj_aux: (∀f1. @⦃0, f1⦄ ≡ 0 → H_coafter_inj f1) →
578 ∀i2,f1. @⦃0, f1⦄ ≡ i2 → H_coafter_inj f1.
579 #H0 #i2 elim i2 -i2 /2 width=1 by/ -H0
580 #i2 #IH #f1 #H1f1 #H2f1 #f #f21 #f22 #H1f #H2f
581 elim (at_inv_pxn … H1f1) -H1f1 [ |*: // ] #g1 #H1g1 #H1
582 elim (coafter_inv_nxx … H1f … H1) -H1f #g #H1g #H
583 lapply (coafter_inv_nxp … H2f … H1 H) -f #H2g
584 /3 width=6 by istot_inv_next/
587 theorem coafter_inj: ∀f1. H_coafter_inj f1.
588 #f1 #H cases (H 0) /3 width=7 by coafter_inj_aux, coafter_inj_O_aux/
591 corec fact coafter_fwd_isid2_O_aux: ∀f1. @⦃0, f1⦄ ≡ 0 →
592 H_coafter_fwd_isid2 f1.
593 #f1 #H1f1 #f2 #f #H #H2f1 #Hf
594 cases (at_inv_pxp … H1f1) -H1f1 [ |*: // ] #g1 #H1
595 lapply (istot_inv_push … H2f1 … H1) -H2f1 #H2g1
596 cases (H2g1 0) #n #Hn
597 cases (coafter_inv_pxx … H … H1) -H * #g2 #g #H #H2 #H0
598 [ lapply (isid_inv_push … Hf … H0) -Hf #Hg
600 /3 width=7 by coafter_tls, istot_tls, at_pxx_tls, isid_tls/
601 | cases (isid_inv_next … Hf … H0)
605 fact coafter_fwd_isid2_aux: (∀f1. @⦃0, f1⦄ ≡ 0 → H_coafter_fwd_isid2 f1) →
606 ∀i2,f1. @⦃0, f1⦄ ≡ i2 → H_coafter_fwd_isid2 f1.
607 #H0 #i2 elim i2 -i2 /2 width=1 by/ -H0
608 #i2 #IH #f1 #H1f1 #f2 #f #H #H2f1 #Hf
609 elim (at_inv_pxn … H1f1) -H1f1 [ |*: // ] #g1 #Hg1 #H1
610 elim (coafter_inv_nxx … H … H1) -H #g #Hg #H0
611 @(IH … Hg1 … Hg) /2 width=3 by istot_inv_next, isid_inv_push/ (**) (* full auto fails *)
614 lemma coafter_fwd_isid2: ∀f1. H_coafter_fwd_isid2 f1.
615 #f1 #f2 #f #Hf #H cases (H 0)
616 /3 width=7 by coafter_fwd_isid2_aux, coafter_fwd_isid2_O_aux/
619 fact coafter_isfin2_fwd_O_aux: ∀f1. @⦃0, f1⦄ ≡ 0 →
620 H_coafter_isfin2_fwd f1.
622 generalize in match Hf1; generalize in match f1; -f1
624 [ /3 width=4 by coafter_isid_inv_dx, isfin_isid/ ]
625 #f2 #_ #IH #f1 #H #Hf1 #f #Hf
626 elim (at_inv_pxp … H) -H [ |*: // ] #g1 #H1
627 lapply (istot_inv_push … Hf1 … H1) -Hf1 #Hg1
629 [ elim (coafter_inv_ppx … Hf) | elim (coafter_inv_pnx … Hf)
630 ] -Hf [1,6: |*: // ] #g #Hg #H0 destruct
631 /5 width=6 by isfin_next, isfin_push, isfin_inv_tls, istot_tls, at_pxx_tls, coafter_tls/
634 fact coafter_isfin2_fwd_aux: (∀f1. @⦃0, f1⦄ ≡ 0 → H_coafter_isfin2_fwd f1) →
635 ∀i2,f1. @⦃0, f1⦄ ≡ i2 → H_coafter_isfin2_fwd f1.
636 #H0 #i2 elim i2 -i2 /2 width=1 by/ -H0
637 #i2 #IH #f1 #H1f1 #f2 #Hf2 #H2f1 #f #Hf
638 elim (at_inv_pxn … H1f1) -H1f1 [ |*: // ] #g1 #Hg1 #H1
639 elim (coafter_inv_nxx … Hf … H1) -Hf #g #Hg #H0
640 lapply (IH … Hg1 … Hg) -i2 -Hg
641 /2 width=4 by istot_inv_next, isfin_push/ (**) (* full auto fails *)
644 lemma coafter_isfin2_fwd: ∀f1. H_coafter_isfin2_fwd f1.
645 #f1 #f2 #Hf2 #Hf1 cases (Hf1 0)
646 /3 width=7 by coafter_isfin2_fwd_aux, coafter_isfin2_fwd_O_aux/
649 lemma coafter_inv_sor: ∀f. 𝐅⦃f⦄ → ∀f2. 𝐓⦃f2⦄ → ∀f1. f2 ~⊚ f1 ≡ f → ∀fa,fb. fa ⋓ fb ≡ f →
650 ∃∃f1a,f1b. f2 ~⊚ f1a ≡ fa & f2 ~⊚ f1b ≡ fb & f1a ⋓ f1b ≡ f1.
652 [ #f #Hf #f2 #Hf2 #f1 #H1f #fa #fb #H2f
653 elim (sor_inv_isid3 … H2f) -H2f //
654 lapply (coafter_fwd_isid2 … H1f ??) -H1f //
655 /3 width=5 by ex3_2_intro, coafter_isid_dx, sor_isid/
656 | #f #_ #IH #f2 #Hf2 #f1 #H1 #fa #fb #H2
657 elim (sor_inv_xxp … H2) -H2 [ |*: // ] #ga #gb #H2f
658 elim (coafter_inv_xxp … H1) -H1 [1,3: * |*: // ] #g2 [ #g1 ] #H1f #Hgf2
659 [ lapply (istot_inv_push … Hf2 … Hgf2) | lapply (istot_inv_next … Hf2 … Hgf2) ] -Hf2 #Hg2
660 elim (IH … Hg2 … H1f … H2f) -f -Hg2
661 /3 width=11 by sor_pp, ex3_2_intro, coafter_refl, coafter_next/
662 | #f #_ #IH #f2 #Hf2 #f1 #H1 #fa #fb #H2
663 elim (coafter_inv_xxn … H1) -H1 [ |*: // ] #g2 #g1 #H1f #Hgf2
664 lapply (istot_inv_push … Hf2 … Hgf2) -Hf2 #Hg2
665 elim (sor_inv_xxn … H2) -H2 [1,3,4: * |*: // ] #ga #gb #H2f
666 elim (IH … Hg2 … H1f … H2f) -f -Hg2
667 /3 width=11 by sor_np, sor_pn, sor_nn, ex3_2_intro, coafter_refl, coafter_push/
671 (* Properties with istot ****************************************************)
673 lemma coafter_sor: ∀f. 𝐅⦃f⦄ → ∀f2. 𝐓⦃f2⦄ → ∀f1. f2 ~⊚ f1 ≡ f → ∀f1a,f1b. f1a ⋓ f1b ≡ f1 →
674 ∃∃fa,fb. f2 ~⊚ f1a ≡ fa & f2 ~⊚ f1b ≡ fb & fa ⋓ fb ≡ f.
676 [ #f #Hf #f2 #Hf2 #f1 #Hf #f1a #f1b #Hf1
677 lapply (coafter_fwd_isid2 … Hf ??) -Hf // #H2f1
678 elim (sor_inv_isid3 … Hf1) -Hf1 //
679 /3 width=5 by coafter_isid_dx, sor_refl, ex3_2_intro/
680 | #f #_ #IH #f2 #Hf2 #f1 #H1 #f1a #f1b #H2
681 elim (coafter_inv_xxp … H1) -H1 [1,3: * |*: // ]
682 [ #g2 #g1 #Hf #Hgf2 #Hgf1
683 elim (sor_inv_xxp … H2) -H2 [ |*: // ] #ga #gb #Hg1
684 lapply (istot_inv_push … Hf2 … Hgf2) -Hf2 #Hg2
685 elim (IH … Hf … Hg1) // -f1 -g1 -IH -Hg2
686 /3 width=11 by coafter_refl, sor_pp, ex3_2_intro/
688 lapply (istot_inv_next … Hf2 … Hgf2) -Hf2 #Hg2
689 elim (IH … Hf … H2) // -f1 -IH -Hg2
690 /3 width=11 by coafter_next, sor_pp, ex3_2_intro/
692 | #f #_ #IH #f2 #Hf2 #f1 #H1 #f1a #f1b #H2
693 elim (coafter_inv_xxn … H1) -H1 [ |*: // ] #g2 #g1 #Hf #Hgf2 #Hgf1
694 lapply (istot_inv_push … Hf2 … Hgf2) -Hf2 #Hg2
695 elim (sor_inv_xxn … H2) -H2 [1,3,4: * |*: // ] #ga #gb #Hg1
696 elim (IH … Hf … Hg1) // -f1 -g1 -IH -Hg2
697 /3 width=11 by coafter_refl, coafter_push, sor_np, sor_pn, sor_nn, ex3_2_intro/
701 (* Properties with after ****************************************************)
703 corec theorem coafter_trans1: ∀f0,f3,f4. f0 ~⊚ f3 ≡ f4 →
704 ∀f1,f2. f1 ~⊚ f2 ≡ f0 →
705 ∀f. f2 ~⊚ f3 ≡ f → f1 ~⊚ f ≡ f4.
706 #f0 #f3 #f4 * -f0 -f3 -f4 #f0 #f3 #f4 #g0 [1,2: #g3 ] #g4
707 [ #Hf4 #H0 #H3 #H4 #g1 #g2 #Hg0 #g #Hg
708 cases (coafter_inv_xxp … Hg0 … H0) -g0
710 cases (coafter_inv_ppx … Hg … H2 H3) -g2 -g3
711 #f #Hf #H /3 width=7 by coafter_refl/
712 | #Hf4 #H0 #H3 #H4 #g1 #g2 #Hg0 #g #Hg
713 cases (coafter_inv_xxp … Hg0 … H0) -g0
715 cases (coafter_inv_pnx … Hg … H2 H3) -g2 -g3
716 #f #Hf #H /3 width=7 by coafter_push/
717 | #Hf4 #H0 #H4 #g1 #g2 #Hg0 #g #Hg
718 cases (coafter_inv_xxn … Hg0 … H0) -g0 *
719 [ #f1 #f2 #Hf0 #H1 #H2
720 cases (coafter_inv_nxx … Hg … H2) -g2
721 #f #Hf #H /3 width=7 by coafter_push/
722 | #f1 #Hf0 #H1 /3 width=6 by coafter_next/
727 corec theorem coafter_trans2: ∀f1,f0,f4. f1 ~⊚ f0 ≡ f4 →
728 ∀f2, f3. f2 ~⊚ f3 ≡ f0 →
729 ∀f. f1 ~⊚ f2 ≡ f → f ~⊚ f3 ≡ f4.
730 #f1 #f0 #f4 * -f1 -f0 -f4 #f1 #f0 #f4 #g1 [1,2: #g0 ] #g4
731 [ #Hf4 #H1 #H0 #H4 #g2 #g3 #Hg0 #g #Hg
732 cases (coafter_inv_xxp … Hg0 … H0) -g0
734 cases (coafter_inv_ppx … Hg … H1 H2) -g1 -g2
735 #f #Hf #H /3 width=7 by coafter_refl/
736 | #Hf4 #H1 #H0 #H4 #g2 #g3 #Hg0 #g #Hg
737 cases (coafter_inv_xxn … Hg0 … H0) -g0 *
738 [ #f2 #f3 #Hf0 #H2 #H3
739 cases (coafter_inv_ppx … Hg … H1 H2) -g1 -g2
740 #f #Hf #H /3 width=7 by coafter_push/
742 cases (coafter_inv_pnx … Hg … H1 H2) -g1 -g2
743 #f #Hf #H /3 width=6 by coafter_next/
745 | #Hf4 #H1 #H4 #f2 #f3 #Hf0 #g #Hg
746 cases (coafter_inv_nxx … Hg … H1) -g1
747 #f #Hg #H /3 width=6 by coafter_next/