proposition: Lemma drestrD (mu : {distr T / R}) (p : pred T) x : mu x = drestr p mu x + drestr (predC p) mu x.
proof: Proof. by rewrite !drestrE !inE; case: ifPn; rewrite /= (addr0, add0r). Qed.
imports: mathcomp(all_ssreflect all_algebra) mathcomp.classical(boolp classical_sets mathcomp_extra) xfinmap ereal reals discrete topology realseq realsum