proposition: Lemma mulVKf x : x != 0 -> cancel ( *%R x^-1) ( *%R x).
proof: Proof. by rewrite -unitfE; apply: mulVKr. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)