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-rw-r--r--theories/Relations/Relation_Definitions.v28
1 files changed, 14 insertions, 14 deletions
diff --git a/theories/Relations/Relation_Definitions.v b/theories/Relations/Relation_Definitions.v
index 762da1ff..c03c4b95 100644
--- a/theories/Relations/Relation_Definitions.v
+++ b/theories/Relations/Relation_Definitions.v
@@ -6,19 +6,19 @@
(* * GNU Lesser General Public License Version 2.1 *)
(************************************************************************)
-(*i $Id: Relation_Definitions.v 9245 2006-10-17 12:53:34Z notin $ i*)
+(*i $Id$ i*)
Section Relation_Definition.
Variable A : Type.
-
+
Definition relation := A -> A -> Prop.
Variable R : relation.
-
+
Section General_Properties_of_Relations.
-
+
Definition reflexive : Prop := forall x:A, R x x.
Definition transitive : Prop := forall x y z:A, R x y -> R y z -> R x z.
Definition symmetric : Prop := forall x y:A, R x y -> R y x.
@@ -32,33 +32,33 @@ Section Relation_Definition.
Section Sets_of_Relations.
-
- Record preorder : Prop :=
+
+ Record preorder : Prop :=
{ preord_refl : reflexive; preord_trans : transitive}.
-
- Record order : Prop :=
+
+ Record order : Prop :=
{ ord_refl : reflexive;
ord_trans : transitive;
ord_antisym : antisymmetric}.
-
- Record equivalence : Prop :=
+
+ Record equivalence : Prop :=
{ equiv_refl : reflexive;
equiv_trans : transitive;
equiv_sym : symmetric}.
-
+
Record PER : Prop := {per_sym : symmetric; per_trans : transitive}.
End Sets_of_Relations.
Section Relations_of_Relations.
-
+
Definition inclusion (R1 R2:relation) : Prop :=
forall x y:A, R1 x y -> R2 x y.
-
+
Definition same_relation (R1 R2:relation) : Prop :=
inclusion R1 R2 /\ inclusion R2 R1.
-
+
Definition commut (R1 R2:relation) : Prop :=
forall x y:A,
R1 y x -> forall z:A, R2 z y -> exists2 y' : A, R2 y' x & R1 z y'.