proposition: Lemma has_expZ mu c F : \E?_[mu] F -> \E?_[mu] (c \*o F).
proof: Proof. move=> heF; have: summable (c \*o (F \* mu)) by apply/summableZ. by apply/eq_summable => x /=; rewrite mulrA. Qed.
imports: mathcomp(all_ssreflect all_algebra) mathcomp.classical(boolp classical_sets mathcomp_extra) xfinmap ereal reals discrete topology realseq realsum