proposition: Lemma dim_span X : \dim <<X>> <= size X.
proof: Proof. by rewrite unlock /dimv genmxE rank_leq_row. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)