proposition: Lemma scalerAl (a : R) (u v : W) : a *: (u * v) = a *: u * v.
proof: Proof. by apply: val_inj; rewrite !(linearZ, rmorphM)/= linearZ scalerAl. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)