proposition: Lemma span_nil : (<<Nil vT>> = 0)%VS.
proof: Proof. by rewrite span_def big_nil. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)