proposition: Lemma mulVc : forall x, x != C0 -> mulc (invc x) x = C1.
proof: Proof. move=> [a b]; rewrite eq_complex => /= hab; rewrite !mulNr opprK. rewrite ![_ / _ * _]mulrAC [b * a]mulrC subrr complexr0 -mulrDl mulfV //. by rewrite paddr_eq0 -!expr2 ?expf_eq0 ?sqr_ge0. Qed.
imports: HB(structures) mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool eqtype ssrnat seq choice fintype) mathcomp(bigop order ssralg ssrint div ssrnum rat poly closed_field) mathcomp(polyrcf matrix mxalgebra tuple mxpoly zmodp binomial realalg) mathcomp(mxpoly)