fact: Definition M : 'M[int]_(2,2) := \matrix_(i,j < 2) 3%:Z.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path ssralg) mathcomp(fintype perm choice matrix bigop zmodp poly polydiv mxpoly) CoqEAL(minor hrel param refinements seqmx) mathcomp(ssrint) CoqEAL(binnat binint seqpoly poly_div binord trivial_seq)