+++ /dev/null
-(**************************************************************************)
-(* ___ *)
-(* ||M|| *)
-(* ||A|| A project by Andrea Asperti *)
-(* ||T|| *)
-(* ||I|| Developers: *)
-(* ||T|| A.Asperti, C.Sacerdoti Coen, *)
-(* ||A|| E.Tassi, S.Zacchiroli *)
-(* \ / *)
-(* \ / This file is distributed under the terms of the *)
-(* v GNU Lesser General Public License Version 2.1 *)
-(* *)
-(**************************************************************************)
-
-set "baseuri" "cic:/matita/nat/plus".
-
-include "nat/nat.ma".
-
-let rec plus n m \def
- match n with
- [ O \Rightarrow m
- | (S p) \Rightarrow S (plus p m) ].
-
-(*CSC: the URI must disappear: there is a bug now *)
-interpretation "natural plus" 'plus x y = (cic:/matita/nat/plus/plus.con x y).
-
-theorem plus_n_O: \forall n:nat. n = n+O.
-intros.elim n.
-simplify.reflexivity.
-simplify.apply eq_f.assumption.
-qed.
-
-theorem plus_n_Sm : \forall n,m:nat. S (n+m) = n+(S m).
-intros.elim n.
-simplify.reflexivity.
-simplify.apply eq_f.assumption.
-qed.
-
-theorem sym_plus: \forall n,m:nat. n+m = m+n.
-intros.elim n.
-simplify.apply plus_n_O.
-simplify.rewrite > H.apply plus_n_Sm.
-qed.
-
-theorem associative_plus : associative nat plus.
-unfold associative.intros.elim x.
-simplify.reflexivity.
-simplify.apply eq_f.assumption.
-qed.
-
-theorem assoc_plus : \forall n,m,p:nat. (n+m)+p = n+(m+p)
-\def associative_plus.
-
-theorem injective_plus_r: \forall n:nat.injective nat nat (\lambda m.n+m).
-intro.simplify.intros 2.elim n.
-exact H.
-apply H.apply inj_S.apply H1.
-qed.
-
-theorem inj_plus_r: \forall p,n,m:nat. p+n = p+m \to n=m
-\def injective_plus_r.
-
-theorem injective_plus_l: \forall m:nat.injective nat nat (\lambda n.n+m).
-intro.simplify.intros.
-apply (injective_plus_r m).
-rewrite < sym_plus.
-rewrite < (sym_plus y).
-assumption.
-qed.
-
-theorem inj_plus_l: \forall p,n,m:nat. n+p = m+p \to n=m
-\def injective_plus_l.