X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Flibrary%2Flogic%2Fconnectives.ma;h=ba229870fbca66c1a860268d30dc9e0e0301b137;hb=01001c883a8151edba81cd03a6f254d24a81c867;hp=bb08b8038bf51c37d533a0889c2493fd04fdc810;hpb=73284b016dc2c195491ab3442457ec9fb76b576f;p=helm.git diff --git a/helm/software/matita/library/logic/connectives.ma b/helm/software/matita/library/logic/connectives.ma index bb08b8038..ba229870f 100644 --- a/helm/software/matita/library/logic/connectives.ma +++ b/helm/software/matita/library/logic/connectives.ma @@ -12,8 +12,6 @@ (* *) (**************************************************************************) -set "baseuri" "cic:/matita/logic/connectives/". - inductive True: Prop \def I : True. @@ -82,3 +80,5 @@ interpretation "exists" 'exists \eta.x = inductive ex2 (A:Type) (P,Q:A \to Prop) : Prop \def ex_intro2: \forall x:A. P x \to Q x \to ex2 A P Q. +definition iff := + \lambda A,B. (A -> B) \land (B -> A).