(* -*- coding: utf-8 -*- *)
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(*         *      The Rocq Prover / The Rocq Development Team           *)
(*  v      *         Copyright INRIA, CNRS and contributors             *)
(* <O___,, * (see version control and CREDITS file for authors & dates) *)
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(*         *     GNU Lesser General Public License Version 2.1          *)
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(** * Typeclass-based relations, tactics and standard instances  This is the basic theory needed to formalize morphisms and setoids.  Author: Matthieu Sozeau Institution: LRI, CNRS UMR 8623 - University Paris Sud *)
Require Export Corelib.Classes.Init.
Generalizable Variables A B C D R S T U l eqA eqB eqC eqD.
(** We allow to unfold the [relation] definition while doing morphism search. *)
Section Defs.
Context {A : Type}.
(** We rebind relational properties in separate classes to be able to overload each proof. *)
Class Reflexive (R : relation A) :=
reflexivity : forall x : A, R x x.
Definition complement (R : relation A) : relation A := fun x y => R x y -> False.
(** Opaque for proof-search. *)
Typeclasses Opaque complement.

(* Specifications: *)
(** These are convertible. *)
Lemma complement_inverse R : complement (flip R) = flip (complement R).
Next Obligation.