ndestruct tactic: mainly bugfixes; the algorithm isn't clean yet, outputting a

[helm.git] / helm / software / matita / nlibrary / logic / connectives.ma

diff --git a/helm/software/matita/nlibrary/logic/connectives.ma b/helm/software/matita/nlibrary/logic/connectives.ma
index 34661dc8015e62a19403fb16e337359acb59c19e..4d085995d4ea1a589af54e8552afdbe2fbf713e3 100644 (file)
--- a/helm/software/matita/nlibrary/logic/connectives.ma
+++ b/helm/software/matita/nlibrary/logic/connectives.ma
@@ -45,6 +45,11 @@ ninductive Ex1 (A:Type[1]) (P:A → CProp[0]) : CProp[1] ≝
 interpretation "exists1" 'exists x = (Ex1 ? x).
 interpretation "exists" 'exists x = (Ex ? x).
 
+ninductive sigma (A : Type[0]) (P : A → CProp[0]) : Type[0] ≝ 
+ sig_intro : ∀x:A.P x → sigma A P. 
+
+interpretation "sigma" 'sigma \eta.p = (sigma ? p). 
+
 nrecord iff (A,B: CProp[0]) : CProp[0] ≝
  { if: A → B;
    fi: B → A