proposition: Lemma adjoin_nil V : <<V & [::]>>%VS = agenv V.
proof: Proof. by rewrite span_nil addv0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype div tuple finfun bigop ssralg) mathcomp(finalg zmodp matrix vector poly)