Let Ω be the sample space of an experiment. Let E be an event with P(E)>0 and define mE(ω) by mE(ω)=m(ω∣E). Prove that mE(ω) is a distribution function on E, that is, that mE(ω)≥0 and that ∑ω∈ΩmE(ω)=1. The function mE is called the conditional distribution given E.