proposition: Lemma root_cst_creal (x : F) : ('X - x%:P).[cst_creal x] == 0.
proof: Proof. apply: eq_crealP; exists_big_modulus m F. by move=> e i e_gt0 hi; rewrite /= subr0 !hornerE subrr normr0. by close. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool eqtype ssrnat seq choice fintype) mathcomp(bigop order ssralg ssrnum ssrint rat poly polydiv polyorder) mathcomp(perm matrix mxpoly polyXY binomial bigenough)