proposition: Lemma sqrtc_eq0 (x : R[i]) : (sqrtc x == 0) = (x == 0).
proof: Proof. apply/eqP/eqP=> [eqs|->]; last by rewrite sqrtc0. by rewrite -[x]sqr_sqrtc eqs exprS mul0r. 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)