proposition: Fact partdom_antisym : antisymmetric (fun x y : 'P_d => partdom x y).
proof: Proof. by move=> x y /andP[Hxy Hyx]; apply val_inj => /=; apply: partdom_anti. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(div ssralg ssrint ssrnum binomial) tools combclass sorted ordtype