added non-builtin notation for exists

actually, the parsing rules is built-in, while the pretty priting one is not

diff --git a/helm/matita/library/logic/connectives.ma b/helm/matita/library/logic/connectives.ma
index 6437bd132c6749b8ea44c58d6486e9f3d310cee0..15b1cfe10d59a44ccf2e28a7476c72e8d7d61392 100644 (file)
--- a/helm/matita/library/logic/connectives.ma
+++ b/helm/matita/library/logic/connectives.ma
@@ -54,7 +54,8 @@ 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.
 
@@ -62,7 +63,15 @@ 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 x y = (cic:/matita/logic/connectives/ex.ind#xpointer(1/1) x y).
+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.
+