proposition: Lemma span_seq1 v : (<<[:: v]>> = <[v]>)%VS.
proof: Proof. by rewrite span_def big_seq1. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)