proposition: Lemma id : IntegralDomain.axiom U.
proof: Proof. move=> x y /(congr1 val)/eqP; rewrite rmorphM /=. by rewrite -!(inj_eq val_inj) rmorph0 -mulf_eq0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)