(* (c) Copyright 2006-2016 Microsoft Corporation and Inria.                  *)
(* Distributed under the terms of CeCILL-B.                                  *)
From mathcomp
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(* This file provides few basic properties of cyclotomic polynomials.         *)
(* We define:                                                                 *)
(*   cyclotomic z n == the factorization of the nth cyclotomic polynomial in  *)
(*                     a ring R in which z is an nth primitive root of unity. *)
(*           'Phi_n == the nth cyclotomic polynomial in int.                  *)
(* This library is quite limited, and should be extended in the future. In    *)
(* particular the irreducibity of 'Phi_n is only stated indirectly, as the    *)
(* fact that its embedding in the algebraics (algC) is the minimal polynomial *)
(* of an nth primitive root of unity.                                         *)
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Set Implicit Arguments.
Unset Strict Implicit.
Unset Printing Implicit Defensive.
Local Open Scope ring_scope.
Section CyclotomicPoly.
Section Ring.
Variable R : ringType.
Definition cyclotomic (z : R) n :=
\prod_(k < n | coprime k n) ('X - (z ^+ k)%:P).

Lemma separable_Xn_sub_1 (R : idomainType) n :
n%:R != 0 :> R -> @separable_poly R ('X^n - 1).