reserve i,j for Element of NAT,
  x,y,z for FinSequence of COMPLEX,
  c for Element of COMPLEX,
  R,R1,R2 for Element of i-tuples_on COMPLEX;

theorem Th32:
  for x,y being complex-valued FinSequence st len x=len y holds
  -(x - y) = -x + y
proof
  let x,y be complex-valued FinSequence;
  assume
A1: len x=len y;
  len (-y) = len y by Th5;
  then -(x - y) = -x +--y by A1,Th29
    .= -x + y;
  hence thesis;
end;
