reserve i,j,n,k for Nat,
  a for Element of COMPLEX,
  R1,R2 for Element of i-tuples_on COMPLEX;

theorem Th49:
  for M being Matrix of COMPLEX st len M > 0 holds SumAll M = SumAll (M@)
proof
  let M be Matrix of COMPLEX;
  assume len M > 0;
  then SumAll M = Sum ColSum M by Th47
    .= SumAll(M@) by Th48;
  hence thesis;
end;
