+++ /dev/null
-(**************************************************************************)
-(* ___ *)
-(* ||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/functions/cocompose_2.ma".
-include "ground/relocation/rtmap_coafter.ma".
-
-(* RELOCATION N-STREAM ******************************************************)
-
-rec definition fun0 (p1:pnat) on p1: rtmap → pnat.
-* * [ | #p2 #f2 @(𝟏) ]
-#f2 cases p1 -p1 [ @(𝟏) ]
-#p1 @(↑(fun0 p1 f2))
-defined.
-
-rec definition fun2 (p1:pnat) on p1: rtmap → rtmap.
-* * [ | #p2 #f2 @(p2⨮f2) ]
-#f2 cases p1 -p1 [ @f2 ]
-#p1 @(fun2 p1 f2)
-defined.
-
-rec definition fun1 (p1:pnat) (f1:rtmap) on p1: rtmap → rtmap.
-* * [ | #p2 #f2 @(p1⨮f1) ]
-#f2 cases p1 -p1 [ @f1 ]
-#p1 @(fun1 p1 f1 f2)
-defined.
-
-corec definition cocompose: rtmap → rtmap → rtmap.
-#f2 * #p1 #f1
-@(stream_cons … (fun0 p1 f2)) @(cocompose (fun2 p1 f2) (fun1 p1 f1 f2))
-defined.
-
-interpretation "functional co-composition (nstream)"
- 'CoCompose f1 f2 = (cocompose f1 f2).
-
-(* Basic properties on funs *************************************************)
-
-(* Note: we need theese since matita blocks recursive δ when ι is blocked *)
-lemma fun0_xn: ∀f2,p1. 𝟏 = fun0 p1 (↑f2).
-* #p2 #f2 * //
-qed.
-
-lemma fun2_xn: ∀f2,p1. f2 = fun2 p1 (↑f2).
-* #p2 #f2 * //
-qed.
-
-lemma fun1_xxn: ∀f2,f1,p1. fun1 p1 f1 (↑f2) = p1⨮f1.
-* #p2 #f2 #f1 * //
-qed.
-
-(* Basic properies on cocompose *********************************************)
-
-lemma cocompose_rew: ∀f2,f1,p1. (fun0 p1 f2)⨮(fun2 p1 f2)~∘(fun1 p1 f1 f2) = f2 ~∘ (p1⨮f1).
-#f2 #f1 #p1 <(stream_rew … (f2~∘(p1⨮f1))) normalize //
-qed.
-
-(* Basic inversion lemmas on compose ****************************************)
-
-lemma cocompose_inv_ppx: ∀f2,f1,f,x. (⫯f2) ~∘ (⫯f1) = x⨮f →
- ∧∧ 𝟏 = x & f2 ~∘ f1 = f.
-#f2 #f1 #f #x
-<cocompose_rew #H destruct
-normalize /2 width=1 by conj/
-qed-.
-
-lemma cocompose_inv_pnx: ∀f2,f1,f,p1,x. (⫯f2) ~∘ (↑p1⨮f1) = x⨮f →
- ∃∃p. ↑p = x & f2 ~∘ (p1⨮f1) = p⨮f.
-#f2 #f1 #f #p1 #x
-<cocompose_rew #H destruct
-@(ex2_intro … (fun0 p1 f2)) // <cocompose_rew
-/3 width=1 by eq_f2/
-qed-.
-
-lemma cocompose_inv_nxx: ∀f2,f1,f,p1,x. (↑f2) ~∘ (p1⨮f1) = x⨮f →
- ∧∧ 𝟏 = x & f2 ~∘ (p1⨮f1) = f.
-#f2 #f1 #f #p1 #x
-<cocompose_rew #H destruct
-/2 width=1 by conj/
-qed-.
-
-(* Specific properties on coafter *******************************************)
-
-corec lemma coafter_total_aux: ∀f2,f1,f. f2 ~∘ f1 = f → f2 ~⊚ f1 ≘ f.
-* #p2 #f2 * #p1 #f1 * #p #f cases p2 -p2
-[ cases p1 -p1
- [ #H cases (cocompose_inv_ppx … H) -H /3 width=7 by coafter_refl, eq_f2/
- | #p1 #H cases (cocompose_inv_pnx … H) -H /3 width=7 by coafter_push/
- ]
-| #p2 >next_rew #H cases (cocompose_inv_nxx … H) -H /3 width=5 by coafter_next/
-]
-qed-.
-
-theorem coafter_total: ∀f2,f1. f2 ~⊚ f1 ≘ f2 ~∘ f1.
-/2 width=1 by coafter_total_aux/ qed.