proposition: Lemma size_basis U n (X : n.-tuple vT) : basis_of U X -> \dim U = n.
proof: Proof. by case/andP=> /eqP <- /eqnP->; apply: size_tuple. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)