fact: Definition mulid m n (I : 'cV[R]_m) (J : 'cV[R]_n) : 'cV[R]_(m * n) := (mxvec (I *m J^T))^T.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice fingroup) mathcomp(matrix bigop zmodp mxalgebra poly) ssrcomplements