proposition: Lemma ker1 m : ker (1%:M : 'M[R]_m) = 0.
proof: Proof. by rewrite -kerK mulmx1. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice matrix bigop zmodp mxalgebra poly) ssrcomplements dvdring stronglydiscrete