proposition: Lemma root_add_algcreal (x y : algcreal) : ((annul_creal (sub_algcreal x (opp_algcreal y))).[x + y] == 0)%CR.
proof: Proof. apply: is_root_annul_creal; apply: eq_crealP. by exists m0=> * /=; rewrite opprK subrr normr0. Qed.
imports: HB(structures) 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 generic_quotient) mathcomp(cauchyreals separable zmodp bigenough)