proposition: Lemma size_scale a p : a != 0 -> size (a *: p) = size p.
proof: Proof. by move/lregP/lreg_size->. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)