X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fdama%2Fconstructive_connectives.ma;h=a0fb66dedf2fd671eacb057796976e5a41b7dd07;hb=7b05e20cb3ed6be79c2fdf94654047b1e58902f9;hp=259357934da012a99aba8adafac2febba1152462;hpb=348acb421355c345a9af0754c1c16508a43eeea5;p=helm.git

diff --git a/matita/dama/constructive_connectives.ma b/matita/dama/constructive_connectives.ma
index 259357934..a0fb66ded 100644
--- a/matita/dama/constructive_connectives.ma
+++ b/matita/dama/constructive_connectives.ma
@@ -18,6 +18,17 @@ inductive or (A,B:Type) : Type \def
    Left : A → or A B
  | Right : B → or A B.
 
-interpretation "classical or" 'or x y =
+interpretation "constructive or" 'or x y =
   (cic:/matita/constructive_connectives/or.ind#xpointer(1/1) x y).
 
+inductive ex (A:Type) (P:A→Prop) : Type \def
+  ex_intro: ∀w:A. P w → ex A P.
+
+notation < "hvbox(Σ ident i opt (: ty) break . p)"
+  right associative with precedence 20
+for @{ 'sigma ${default
+  @{\lambda ${ident i} : $ty. $p)}
+  @{\lambda ${ident i} . $p}}}.
+
+interpretation "constructive exists" 'sigma \eta.x =
+  (cic:/matita/constructive_connectives/ex.ind#xpointer(1/1) _ x).