
theorem Huk1:
  for f being real-valued FinSequence holds
    Sum f = (len f) * (Mean f)
  proof
    let f be real-valued FinSequence;
    per cases;
    suppose
      len f <> 0;
      hence thesis by XCMPLX_1:87;
    end;
    suppose len f = 0; then
      f = <*>REAL;
      hence thesis by RVSUM_1:72;
    end;
  end;
