proposition: Lemma pinvmx_free m n (A : 'M[F]_(m, n)) : row_full A -> row_free (pinvmx A).
proof: Proof. by move=> /mulVpmx pAA1; apply/row_freeP; exists A. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype finfun bigop finset fingroup perm order) mathcomp(div prime binomial ssralg finalg zmodp matrix)