proposition: Lemma dvdr_lsubmx m0 n0 n1 x (M : 'M[R]_(m0,n0 + n1)) : (forall i j, x %| M i j) -> forall i j, x %| (lsubmx M) i j.
proof: Proof. by move=> hM i j; rewrite !mxE. Qed.
imports: HB(structures) Coq(ssreflect ssrfun ssrbool Arith.Wf_nat) mathcomp(eqtype ssrnat div seq path) mathcomp(ssralg fintype perm tuple choice generic_quotient) mathcomp(matrix bigop zmodp mxalgebra poly) stronglydiscrete