theorem Th15:
  for F be Function of Omega1, Omega2
  holds F is random_variable of
  Trivial-SigmaField Omega1, Trivial-SigmaField Omega2
  proof
    let F be Function of Omega1, Omega2;
    set S1 = Trivial-SigmaField Omega1;
    set S2 = Trivial-SigmaField Omega2;
    for y being set st y in S2 holds F"y in S1;
    hence thesis by FINANCE1:def 5;
  end;
