reserve T for non empty TopSpace,
  a, b, c, d for Point of T;
reserve X for non empty pathwise_connected TopSpace,
  a1, b1, c1, d1 for Point of X;

theorem
  for P be Path of a1, b1, Q be constant Path of b1, b1 holds P + Q, P
  are_homotopic by Th80,BORSUK_2:def 3;
