proposition: Lemma drestrE (mu : {distr T / R}) x : drestr mu x = if p x then mu x else 0.
proof: Proof. by unlock drestr. Qed.
imports: mathcomp(all_ssreflect all_algebra) mathcomp.classical(boolp classical_sets mathcomp_extra) xfinmap ereal reals discrete topology realseq realsum