X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;ds=sidebyside;f=matita%2Fmatita%2Flib%2Fbasics%2Flogic.ma;h=70e743e993ac96c12cdbf7a4a56cdc23bc8280b6;hb=0d640fb063fd7faed55d2c701a0c905bf86d4bfa;hp=b6a5d59b7e09a575ab43c3361cc33a0ae28eafdf;hpb=bc477154d15f6979c948f9af602199af547d193e;p=helm.git diff --git a/matita/matita/lib/basics/logic.ma b/matita/matita/lib/basics/logic.ma index b6a5d59b7..70e743e99 100644 --- a/matita/matita/lib/basics/logic.ma +++ b/matita/matita/lib/basics/logic.ma @@ -91,21 +91,17 @@ unification hint 0 ≔ T,a,b; inductive True: Prop ≝ I : True. -interpretation "logical true" 'true = True. - inductive False: Prop ≝ . -interpretation "logical false" 'false = False. - (* ndefinition Not: Prop → Prop ≝ -λA. A → ⊥. *) +λA. A → False. *) inductive Not (A:Prop): Prop ≝ -nmk: (A → ⊥) → Not A. +nmk: (A → False) → Not A. interpretation "logical not" 'not x = (Not x). -theorem absurd : ∀A:Prop. A → ¬A → ⊥. +theorem absurd : ∀A:Prop. A → ¬A → False. #A #H #Hn (elim Hn); /2/; qed. (*