X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Fdama%2Fconstructive_higher_order_relations.ma;h=789c7c9c50df894f8c4cb5270278f7009d6afa49;hb=c0f86a886451a0df3b42a1435e21b5def9f34792;hp=cf58e2640ec6a6472dd9731286cd9d0bfcdb9b9b;hpb=475120bb8ccfe5877bbe294006170ed7ab0b1fcd;p=helm.git

diff --git a/helm/software/matita/dama/constructive_higher_order_relations.ma b/helm/software/matita/dama/constructive_higher_order_relations.ma
index cf58e2640..789c7c9c5 100644
--- a/helm/software/matita/dama/constructive_higher_order_relations.ma
+++ b/helm/software/matita/dama/constructive_higher_order_relations.ma
@@ -35,3 +35,16 @@ definition associative ≝
 
 definition commutative ≝
  λC:Type.λop:C→C→C.λeq:C→C→Type.∀x,y. eq (op x y) (op y x).
+
+alias id "antisymmetric" = "cic:/matita/higher_order_defs/relations/antisymmetric.con".
+theorem antisimmetric_to_cotransitive_to_transitive:
+ ∀C:Type.∀le:C→C→Prop. antisymmetric ? le → cotransitive ? le → transitive ? le.  
+intros (T f Af cT); unfold transitive; intros (x y z fxy fyz);
+lapply (cT ??z fxy) as H; cases H; [assumption] cases (Af ? ? fyz H1);
+qed.
+
+lemma Or_symmetric: symmetric ? Or.
+unfold; intros (x y H); cases H; [right|left] assumption;
+qed.
+
+  
\ No newline at end of file