fact: Definition scalar_seqmx m (x : A) := diag_seqmx (const_seqmx 1%N m x).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq ssralg) mathcomp(path choice fintype tuple finset bigop poly matrix mxpoly) CoqEAL(hrel param refinements trivial_seq)