X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Flibrary%2Flogic%2Fcprop_connectives.ma;h=31cd9c576c236355b73e9335319c88c9b97d1c95;hb=070b11daefc90ecc20ebee73acc550aeac1c627b;hp=3b43ef3993670c4699354fd8417d37cda8e83025;hpb=c2bf3797d41b0fd06588f5c7d0fbd02d1219371d;p=helm.git

diff --git a/helm/software/matita/library/logic/cprop_connectives.ma b/helm/software/matita/library/logic/cprop_connectives.ma
index 3b43ef399..31cd9c576 100644
--- a/helm/software/matita/library/logic/cprop_connectives.ma
+++ b/helm/software/matita/library/logic/cprop_connectives.ma
@@ -58,6 +58,21 @@ notation < "hvbox(a break ∧ b break ∧ c break ∧ d)" with precedence 35 for
  
 interpretation "constructive quaternary and" 'and4 x y z t = (And4 x y z t).
 
+record Iff (A,B:CProp) : CProp ≝
+ { if: A → B;
+   fi: B → A
+ }.
+ 
+record Iff1 (A,B:CProp) : CProp ≝
+ { if1: A → B;
+   fi1: B → A
+ }.
+ 
+interpretation "logical iff" 'iff x y = (Iff x y).
+
+notation "hvbox(a break ⇔ b)" right associative with precedence 25 for @{'iff1 $a $b}.
+interpretation "logical iff type1" 'iff1 x y = (Iff1 x y).
+
 inductive exT (A:Type) (P:A→CProp) : CProp ≝
   ex_introT: ∀w:A. P w → exT A P.
   
@@ -85,6 +100,26 @@ interpretation "exT \snd" 'pi2 = (pi2exT _ _).
 interpretation "exT \snd" 'pi2a x = (pi2exT _ _ x).
 interpretation "exT \snd" 'pi2b x y = (pi2exT _ _ x y).
 
+inductive exP (A:Type) (P:A→Prop) : CProp ≝
+  ex_introP: ∀w:A. P w → exP A P.
+  
+interpretation "dependent pair for Prop" 'dependent_pair a b = 
+  (ex_introP _ _ a b).
+
+interpretation "CProp exists for Prop" 'exists \eta.x = (exP _ x).
+
+definition pi1exP ≝ λA,P.λx:exP A P.match x with [ex_introP x _ ⇒ x].
+definition pi2exP ≝ 
+  λA,P.λx:exP A P.match x return λx.P (pi1exP ?? x) with [ex_introP _ p ⇒ p].
+
+interpretation "exP \fst" 'pi1 = (pi1exP _ _).
+interpretation "exP \fst" 'pi1a x = (pi1exP _ _ x).
+interpretation "exP \fst" 'pi1b x y = (pi1exP _ _ x y).
+interpretation "exP \snd" 'pi2 = (pi2exP _ _).
+interpretation "exP \snd" 'pi2a x = (pi2exP _ _ x).
+interpretation "exP \snd" 'pi2b x y = (pi2exP _ _ x y).
+
+
 inductive exT23 (A:Type) (P:A→CProp) (Q:A→CProp) (R:A→A→CProp) : CProp ≝
   ex_introT23: ∀w,p:A. P w → Q p → R w p → exT23 A P Q R.