theorem Th29:
  for n being non zero Nat, p being object
  st p in dom Euler_factorization_2 n holds p is Prime
  proof
    let n be non zero Nat, p be object;
    dom Euler_factorization_2 n c= SetPrimes by RELAT_1:def 18;
    hence thesis by NEWTON:def 6;
end;
