proposition: Lemma scalerK a : a != 0 -> cancel ( *:%R a : V -> V) ( *:%R a^-1).
proof: Proof. by move=> nz_a v; rewrite scalerA mulVf // scale1r. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)