proposition: Lemma mulIf x : x != 0 -> injective ( *%R^~ x).
proof: Proof. by move=> nz_x y z; rewrite -!(mulrC x); apply: mulfI. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)