-(**************************************************************************)
-(* ___ *)
-(* ||M|| *)
-(* ||A|| A project by Andrea Asperti *)
-(* ||T|| *)
-(* ||I|| Developers: *)
-(* ||T|| The HELM team. *)
-(* ||A|| http://helm.cs.unibo.it *)
-(* \ / *)
-(* \ / This file is distributed under the terms of the *)
-(* v GNU General Public License Version 2 *)
-(* *)
-(**************************************************************************)
-
-include "ground/notation/relations/rafter_3.ma".
-include "ground/xoa/ex_3_2.ma".
-include "ground/relocation/gr_tl.ma".
-
-(* RELATIONAL COMPOSITION FOR GENERIC RELOCATION MAPS ***********************)
-
-(*** after *)
-coinductive gr_after: relation3 gr_map gr_map gr_map ≝
-(*** after_refl *)
-| gr_after_refl (f1) (f2) (f) (g1) (g2) (g):
- gr_after f1 f2 f → ⫯f1 = g1 → ⫯f2 = g2 → ⫯f = g → gr_after g1 g2 g
-(*** after_push *)
-| gr_after_push (f1) (f2) (f) (g1) (g2) (g):
- gr_after f1 f2 f → ⫯f1 = g1 → ↑f2 = g2 → ↑f = g → gr_after g1 g2 g
-(*** after_next *)
-| gr_after_next (f1) (f2) (f) (g1) (g):
- gr_after f1 f2 f → ↑f1 = g1 → ↑f = g → gr_after g1 f2 g
-.
-
-interpretation
- "relational composition (generic relocation maps)"
- 'RAfter f1 f2 f = (gr_after f1 f2 f).
-
-(* Basic inversions *********************************************************)
-
-(*** after_inv_ppx *)
-lemma gr_after_inv_push_bi:
- ∀g1,g2,g. g1 ⊚ g2 ≘ g → ∀f1,f2. ⫯f1 = g1 → ⫯f2 = g2 →
- ∃∃f. f1 ⊚ f2 ≘ f & ⫯f = g.
-#g1 #g2 #g * -g1 -g2 -g #f1 #f2 #f #g1
-[ #g2 #g #Hf #H1 #H2 #H #x1 #x2 #Hx1 #Hx2 destruct
- >(eq_inv_gr_push_bi … Hx1) >(eq_inv_gr_push_bi … Hx2) -x2 -x1
- /2 width=3 by ex2_intro/
-| #g2 #g #_ #_ #H2 #_ #x1 #x2 #_ #Hx2 destruct
- elim (eq_inv_gr_push_next … Hx2)
-| #g #_ #H1 #_ #x1 #x2 #Hx1 #_ destruct
- elim (eq_inv_gr_push_next … Hx1)
-]
-qed-.
-
-(*** after_inv_pnx *)
-lemma gr_after_inv_push_next:
- ∀g1,g2,g. g1 ⊚ g2 ≘ g → ∀f1,f2. ⫯f1 = g1 → ↑f2 = g2 →
- ∃∃f. f1 ⊚ f2 ≘ f & ↑f = g.
-#g1 #g2 #g * -g1 -g2 -g #f1 #f2 #f #g1
-[ #g2 #g #_ #_ #H2 #_ #x1 #x2 #_ #Hx2 destruct
- elim (eq_inv_gr_next_push … Hx2)
-| #g2 #g #Hf #H1 #H2 #H3 #x1 #x2 #Hx1 #Hx2 destruct
- >(eq_inv_gr_push_bi … Hx1) >(eq_inv_gr_next_bi … Hx2) -x2 -x1
- /2 width=3 by ex2_intro/
-| #g #_ #H1 #_ #x1 #x2 #Hx1 #_ destruct
- elim (eq_inv_gr_push_next … Hx1)
-]
-qed-.
-
-(*** after_inv_nxx *)
-lemma gr_after_inv_next_sn:
- ∀g1,f2,g. g1 ⊚ f2 ≘ g → ∀f1. ↑f1 = g1 →
- ∃∃f. f1 ⊚ f2 ≘ f & ↑f = g.
-#g1 #f2 #g * -g1 -f2 -g #f1 #f2 #f #g1
-[ #g2 #g #_ #H1 #_ #_ #x1 #Hx1 destruct
- elim (eq_inv_gr_next_push … Hx1)
-| #g2 #g #_ #H1 #_ #_ #x1 #Hx1 destruct
- elim (eq_inv_gr_next_push … Hx1)
-| #g #Hf #H1 #H #x1 #Hx1 destruct
- >(eq_inv_gr_next_bi … Hx1) -x1
- /2 width=3 by ex2_intro/
-]
-qed-.
-
-(* Advanced inversions ******************************************************)
-
-(*** after_inv_ppp *)
-lemma gr_after_inv_push_bi_push:
- ∀g1,g2,g. g1 ⊚ g2 ≘ g →
- ∀f1,f2,f. ⫯f1 = g1 → ⫯f2 = g2 → ⫯f = g → f1 ⊚ f2 ≘ f.
-#g1 #g2 #g #Hg #f1 #f2 #f #H1 #H2 #H elim (gr_after_inv_push_bi … Hg … H1 H2) -g1 -g2
-#x #Hf #Hx destruct <(eq_inv_gr_push_bi … Hx) -f //
-qed-.
-
-(*** after_inv_ppn *)
-lemma gr_after_inv_push_bi_next:
- ∀g1,g2,g. g1 ⊚ g2 ≘ g →
- ∀f1,f2,f. ⫯f1 = g1 → ⫯f2 = g2 → ↑f = g → ⊥.
-#g1 #g2 #g #Hg #f1 #f2 #f #H1 #H2 #H elim (gr_after_inv_push_bi … Hg … H1 H2) -g1 -g2
-#x #Hf #Hx destruct elim (eq_inv_gr_push_next … Hx)
-qed-.
-
-(*** after_inv_pnn *)
-lemma gr_after_inv_push_next_next:
- ∀g1,g2,g. g1 ⊚ g2 ≘ g →
- ∀f1,f2,f. ⫯f1 = g1 → ↑f2 = g2 → ↑f = g → f1 ⊚ f2 ≘ f.
-#g1 #g2 #g #Hg #f1 #f2 #f #H1 #H2 #H elim (gr_after_inv_push_next … Hg … H1 H2) -g1 -g2
-#x #Hf #Hx destruct <(eq_inv_gr_next_bi … Hx) -f //
-qed-.
-
-(*** after_inv_pnp *)
-lemma gr_after_inv_push_next_push:
- ∀g1,g2,g. g1 ⊚ g2 ≘ g →
- ∀f1,f2,f. ⫯f1 = g1 → ↑f2 = g2 → ⫯f = g → ⊥.
-#g1 #g2 #g #Hg #f1 #f2 #f #H1 #H2 #H elim (gr_after_inv_push_next … Hg … H1 H2) -g1 -g2
-#x #Hf #Hx destruct elim (eq_inv_gr_next_push … Hx)
-qed-.
-
-(*** after_inv_nxn *)
-lemma gr_after_inv_next_sn_next:
- ∀g1,f2,g. g1 ⊚ f2 ≘ g →
- ∀f1,f. ↑f1 = g1 → ↑f = g → f1 ⊚ f2 ≘ f.
-#g1 #f2 #g #Hg #f1 #f #H1 #H elim (gr_after_inv_next_sn … Hg … H1) -g1
-#x #Hf #Hx destruct <(eq_inv_gr_next_bi … Hx) -f //
-qed-.
-
-(*** after_inv_nxp *)
-lemma gr_after_inv_next_sn_push:
- ∀g1,f2,g. g1 ⊚ f2 ≘ g →
- ∀f1,f. ↑f1 = g1 → ⫯f = g → ⊥.
-#g1 #f2 #g #Hg #f1 #f #H1 #H elim (gr_after_inv_next_sn … Hg … H1) -g1
-#x #Hf #Hx destruct elim (eq_inv_gr_next_push … Hx)
-qed-.
-
-(*** after_inv_pxp *)
-lemma gr_after_inv_push_sn_push:
- ∀g1,g2,g. g1 ⊚ g2 ≘ g →
- ∀f1,f. ⫯f1 = g1 → ⫯f = g →
- ∃∃f2. f1 ⊚ f2 ≘ f & ⫯f2 = g2.
-#g1 #g2 elim (gr_map_split_tl g2)
-#Hg2 #g #Hg #f1 #f #H1 #H
-[ lapply (gr_after_inv_push_bi_push … Hg … H1 … H) -g1 -g
- /2 width=3 by ex2_intro/
-| elim (gr_after_inv_push_next_push … Hg … H1 … H) -g1 -g -f1 -f //
-]
-qed-.
-
-(*** after_inv_pxn *)
-lemma gr_after_inv_push_sn_next:
- ∀g1,g2,g. g1 ⊚ g2 ≘ g →
- ∀f1,f. ⫯f1 = g1 → ↑f = g →
- ∃∃f2. f1 ⊚ f2 ≘ f & ↑f2 = g2.
-#g1 #g2 elim (gr_map_split_tl g2)
-#Hg2 #g #Hg #f1 #f #H1 #H
-[ elim (gr_after_inv_push_bi_next … Hg … H1 … H) -g1 -g -f1 -f //
-| lapply (gr_after_inv_push_next_next … Hg … H1 … H) -g1 -g
- /2 width=3 by ex2_intro/
-]
-qed-.
-
-(*** after_inv_xxp *)
-lemma gr_after_inv_push:
- ∀g1,g2,g. g1 ⊚ g2 ≘ g → ∀f. ⫯f = g →
- ∃∃f1,f2. f1 ⊚ f2 ≘ f & ⫯f1 = g1 & ⫯f2 = g2.
-#g1 elim (gr_map_split_tl g1)
-#Hg1 #g2 #g #Hg #f #H
-[ elim (gr_after_inv_push_sn_push … Hg … H) -g /2 width=5 by ex3_2_intro/
-| elim (gr_after_inv_next_sn_push … Hg … H) -g2 -g -f //
-]
-qed-.
-
-(*** after_inv_xxn *)
-lemma gr_after_inv_next:
- ∀g1,g2,g. g1 ⊚ g2 ≘ g → ∀f. ↑f = g →
- ∨∨ ∃∃f1,f2. f1 ⊚ f2 ≘ f & ⫯f1 = g1 & ↑f2 = g2
- | ∃∃f1. f1 ⊚ g2 ≘ f & ↑f1 = g1.
-#g1 elim (gr_map_split_tl g1)
-#Hg1 #g2 #g #Hg #f #H
-[ elim (gr_after_inv_push_sn_next … Hg … H) -g
- /3 width=5 by or_introl, ex3_2_intro/
-| /4 width=5 by gr_after_inv_next_sn_next, or_intror, ex2_intro/
-]
-qed-.
-
-(*** after_inv_pxx *)
-lemma gr_after_inv_push_sn:
- ∀g1,g2,g. g1 ⊚ g2 ≘ g → ∀f1. ⫯f1 = g1 →
- ∨∨ ∃∃f2,f. f1 ⊚ f2 ≘ f & ⫯f2 = g2 & ⫯f = g
- | ∃∃f2,f. f1 ⊚ f2 ≘ f & ↑f2 = g2 & ↑f = g.
-#g1 #g2 elim (gr_map_split_tl g2)
-#Hg2 #g #Hg #f1 #H
-[ elim (gr_after_inv_push_bi … Hg … H) -g1
- /3 width=5 by or_introl, ex3_2_intro/
-| elim (gr_after_inv_push_next … Hg … H) -g1
- /3 width=5 by or_intror, ex3_2_intro/
-]
-qed-.