reserve
  x for object, X for set,
  i, n, m for Nat,
  r, s for Real,
  c, c1, c2, d for Complex,
  f, g for complex-valued Function,
  g1 for n-element complex-valued FinSequence,
  f1 for n-element real-valued FinSequence,
  T for non empty TopSpace,
  p for Element of TOP-REAL n;

theorem
  f(/)c - g(/)c = (f-g)(/)c
  proof
    thus f(/)c - g(/)c = f(/)c + (-g)(/)c by VALUED_2:30
    .= (f-g)(/)c by Th4;
  end;
