more comments added

[helm.git] / helm / matita / library / logic / connectives.ma

diff --git a/helm/matita/library/logic/connectives.ma b/helm/matita/library/logic/connectives.ma
index 057bed878b98c838b3d9f962179f794d4b0e1224..a8cba2b4a394f15584f779fc7749d713a94ad694 100644 (file)
--- a/helm/matita/library/logic/connectives.ma
+++ b/helm/matita/library/logic/connectives.ma
@@ -54,12 +54,24 @@ inductive Or (A,B:Prop) : Prop \def
    | or_intror : B \to (Or A B).
 
 (*CSC: the URI must disappear: there is a bug now *)
-interpretation "logical or" 'or x y = (cic:/matita/logic/connectives/Or.ind#xpointer(1/1) x y).
+interpretation "logical or" 'or x y =
+  (cic:/matita/logic/connectives/Or.ind#xpointer(1/1) x y).
    
-definition decidable : Prop \to Prop \def \lambda A:Prop. A \lor \not A.
+definition decidable : Prop \to Prop \def \lambda A:Prop. A \lor \lnot A.
 
 inductive ex (A:Type) (P:A \to Prop) : Prop \def
     ex_intro: \forall x:A. P x \to ex A P.
 
+(*CSC: the URI must disappear: there is a bug now *)
+interpretation "exists" 'exists \eta.x =
+  (cic:/matita/logic/connectives/ex.ind#xpointer(1/1) _ x).
+
+notation < "hvbox(\exists ident i opt (: ty) break . p)"
+  right associative with precedence 20
+for @{ 'exists ${default
+  @{\lambda ${ident i} : $ty. $p)}
+  @{\lambda ${ident i} . $p}}}.
+
 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.
+