proposition: Lemma simmxRL {P A B} : P \in unitmx -> reflect (B = P *m A *m invmx P) (A ~_P B).
proof: Proof. by move=> ?; apply: (iffP eqP); rewrite conjumx. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(div fintype tuple finfun bigop fingroup perm) mathcomp(ssralg zmodp matrix mxalgebra poly polydiv)