proposition: Lemma card_primeChar : #|R| = (p ^ n)%N.
proof: Proof. by rewrite /n -cardsT {1}(card_pgroup primeChar_pgroup). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype div tuple bigop prime finset fingroup) mathcomp(ssralg poly polydiv morphism action countalg) mathcomp(finalg zmodp cyclic center pgroup abelian matrix) mathcomp(mxpoly vector falgebra fieldext separable galois)