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+(************************************************************************)
+(* v * The Coq Proof Assistant / The Coq Development Team *)
+(* <O___,, * CNRS-Ecole Polytechnique-INRIA Futurs-Universite Paris Sud *)
+(* \VV/ **************************************************************)
+(* // * This file is distributed under the terms of the *)
+(* * GNU Lesser General Public License Version 2.1 *)
+(************************************************************************)
+
+(*i $Id: Operators_Properties.v,v 1.7.2.1 2004/07/16 19:31:16 herbelin Exp $ i*)
+
+(****************************************************************************)
+(* Bruno Barras *)
+(****************************************************************************)
+
+Require Import Relation_Definitions.
+Require Import Relation_Operators.
+
+
+Section Properties.
+
+ Variable A : Set.
+ Variable R : relation A.
+
+ Let incl (R1 R2:relation A) : Prop := forall x y:A, R1 x y -> R2 x y.
+
+Section Clos_Refl_Trans.
+
+ Lemma clos_rt_is_preorder : preorder A (clos_refl_trans A R).
+apply Build_preorder.
+exact (rt_refl A R).
+
+exact (rt_trans A R).
+Qed.
+
+
+
+Lemma clos_rt_idempotent :
+ incl (clos_refl_trans A (clos_refl_trans A R)) (clos_refl_trans A R).
+red in |- *.
+induction 1; auto with sets.
+intros.
+apply rt_trans with y; auto with sets.
+Qed.
+
+ Lemma clos_refl_trans_ind_left :
+ forall (A:Set) (R:A -> A -> Prop) (M:A) (P:A -> Prop),
+ P M ->
+ (forall P0 N:A, clos_refl_trans A R M P0 -> P P0 -> R P0 N -> P N) ->
+ forall a:A, clos_refl_trans A R M a -> P a.
+intros.
+generalize H H0.
+clear H H0.
+elim H1; intros; auto with sets.
+apply H2 with x; auto with sets.
+
+apply H3.
+apply H0; auto with sets.
+
+intros.
+apply H5 with P0; auto with sets.
+apply rt_trans with y; auto with sets.
+Qed.
+
+
+End Clos_Refl_Trans.
+
+
+Section Clos_Refl_Sym_Trans.
+
+ Lemma clos_rt_clos_rst :
+ inclusion A (clos_refl_trans A R) (clos_refl_sym_trans A R).
+red in |- *.
+induction 1; auto with sets.
+apply rst_trans with y; auto with sets.
+Qed.
+
+ Lemma clos_rst_is_equiv : equivalence A (clos_refl_sym_trans A R).
+apply Build_equivalence.
+exact (rst_refl A R).
+
+exact (rst_trans A R).
+
+exact (rst_sym A R).
+Qed.
+
+ Lemma clos_rst_idempotent :
+ incl (clos_refl_sym_trans A (clos_refl_sym_trans A R))
+ (clos_refl_sym_trans A R).
+red in |- *.
+induction 1; auto with sets.
+apply rst_trans with y; auto with sets.
+Qed.
+
+End Clos_Refl_Sym_Trans.
+
+End Properties. \ No newline at end of file