proposition: Lemma similar_refl n (A : 'M[R]_n) : similar A A.
proof: Proof. split=> //; exists 1%:M; first by rewrite unitmx1. by rewrite conform_mx_id mulmx1 mul1mx. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype fintype finfun ssrnat seq) mathcomp(choice ssralg poly polydiv mxpoly matrix bigop) mathcomp(mxalgebra perm fingroup tuple) mxstructure dvdring