update in ground

[helm.git] / matita / matita / contribs / lambdadelta / ground / lib / logic.ma

diff --git a/matita/matita/contribs/lambdadelta/ground/lib/logic.ma b/matita/matita/contribs/lambdadelta/ground/lib/logic.ma
index dc721648096a70f8dd38ae3c689328a03eccf47f..8786e77aeb7556e003d1041be68190c27e7d1d10 100644 (file)
--- a/matita/matita/contribs/lambdadelta/ground/lib/logic.ma
+++ b/matita/matita/contribs/lambdadelta/ground/lib/logic.ma
@@ -18,12 +18,22 @@ include "ground/notation/xoa/true_0.ma".
 include "ground/notation/xoa/or_2.ma".
 include "ground/notation/xoa/and_2.ma".
 
-interpretation "logical false" 'false = False.
+interpretation
+  "false (logic)"
+  'false = False.
 
-interpretation "logical true" 'true = True.
+interpretation
+  "true (logic)"
+  'true = True.
 
-(* Logical properties missing in the basic library **************************)
+(* LOGIC ********************************************************************)
 
-lemma commutative_and: ∀A,B. A ∧ B → B ∧ A.
+definition negation (A:Prop): Prop ≝
+           A → ⊥.
+
+(* Constructions with land **************************************************)
+
+lemma commutative_and (A) (B):
+      A ∧ B → B ∧ A.
 #A #B * /2 width=1 by conj/
 qed-.