proposition: Lemma in_dinsupp x (mu : {distr T / R}) : (x \in dinsupp mu) = (mu x != 0).
proof: Proof. by []. Qed.
imports: mathcomp(all_ssreflect all_algebra) mathcomp.classical(boolp classical_sets mathcomp_extra) xfinmap ereal reals discrete topology realseq realsum