proposition: Lemma eqid_tr_mxvec m n (I : 'M[R]_(m,n)) : ((mxvec I)^T :=: (mxvec I^T)^T)%IS.
proof: Proof. by apply/eqidP; rewrite -[I in X in _ && (_ <= X)%IS]trmxK !subid_tr_mxvec. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice fingroup) mathcomp(matrix bigop zmodp mxalgebra poly) ssrcomplements