let Omega be non empty set ; :: thesis: for Sigma being SigmaField of Omega
for f, g being Real-Valued-Random-Variable of Sigma holds f + g is Real-Valued-Random-Variable of Sigma

let Sigma be SigmaField of Omega; :: thesis: for f, g being Real-Valued-Random-Variable of Sigma holds f + g is Real-Valued-Random-Variable of Sigma
let f, g be Real-Valued-Random-Variable of Sigma; :: thesis: f + g is Real-Valued-Random-Variable of Sigma
consider X being Element of Sigma such that
P1: ( X = Omega & f is_measurable_on X ) by def1;
consider Y being Element of Sigma such that
P2: ( Y = Omega & g is_measurable_on Y ) by def1;
thus f + g is Real-Valued-Random-Variable of Sigma by def1, P1, P2, MESFUNC6:26; :: thesis: verum