proposition: Lemma inj1_is_mono : is_mono inj1.
proof: Proof. move=> P phi; rewrite /eqmor !subr0 /= mul_mx_row mulmx1 mulmx0. move=> /dvdmxP [X]; rewrite -[X]hsubmxK mul_row_block. by rewrite !mulmx0 addr0 add0r => /eq_row_mx[-> _]; rewrite dvdmxMl. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice matrix bigop zmodp mxalgebra poly) ssrcomplements stronglydiscrete coherent edr