From: Andrea Asperti Date: Wed, 17 Mar 2010 11:47:03 +0000 (+0000) Subject: Nuova definizione della negazione. X-Git-Tag: make_still_working~3005 X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=commitdiff_plain;h=d3d67acad6b7a946036c38bd2096609a29fef773;p=helm.git Nuova definizione della negazione. --- diff --git a/helm/software/matita/nlibrary/basics/eq.ma b/helm/software/matita/nlibrary/basics/eq.ma index 73abc9f09..61047a474 100644 --- a/helm/software/matita/nlibrary/basics/eq.ma +++ b/helm/software/matita/nlibrary/basics/eq.ma @@ -25,8 +25,17 @@ ntheorem symmetric_eq: ∀A:Type. symmetric A (eq A). ntheorem transitive_eq : ∀A:Type. transitive A (eq A). #A; #x; #y; #z; #H1; #H2; nrewrite > H1; //; nqed. +(* ntheorem symmetric_not_eq: ∀A:Type. symmetric A (λx,y.x ≠ y). +/3/; nqed. +*) + +ntheorem symmetric_not_eq: ∀A:Type. ∀x,y:A. x ≠ y → y ≠ x. +/3/; nqed. + +(* #A; #x; #y; #H; #K; napply H; napply symmetric_eq; //; nqed. +*) ntheorem eq_f: ∀A,B:Type.∀f:A→B.∀x,y:A. x=y → f x = f y. #A; #B; #f; #x; #y; #H; nrewrite > H; //; nqed.