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

theorem Th21:
  for F being FinSequence of COMPLEX st len F >= 1 holds Sum(F*') = (Sum F)*'
proof
  let F be FinSequence of COMPLEX;
  assume len F >= 1;
  then len (F*') >= 1 by COMPLSP2:def 1;
  hence thesis by Th20;
end;
