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, Q be constant Path of a, a holds P, Q are_homotopic
proof
  let P, Q be constant Path of a, a;
  P = I[01] --> a & Q = I[01] --> a by BORSUK_2:5;
  hence thesis by BORSUK_2:12;
end;
