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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) *)
(*   \VV/  **************************************************************)
(*    //   *    This file is distributed under the terms of the         *)
(*         *     GNU Lesser General Public License Version 2.1          *)
(*         *     (see LICENSE file for the text of the license)         *)
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Local Open Scope Z_scope.
(** Factorization lemmas *)

Lemma OMEGA20 x y z : Zne x 0 -> y = 0 -> Zne (x + y * z) 0.
Definition fast_Zplus_comm (x y : Z) (P : Z -> Prop)
(H : P (y + x)) := eq_ind_r P H (Z.add_comm x y).