proposition: Lemma fgscaleA c1 c2 g : c1 *:g (c2 *:g g) = (c1 * c2) *:g g.
proof: Proof. by apply/malgP=> x; rewrite !fgscaleE mulrA. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path choice finset fintype finfun) mathcomp(tuple bigop ssralg ssrint ssrnum) xfinmap