reserve T,U for non empty TopSpace;
reserve t for Point of T;
reserve n for Nat;

theorem Th4:
  for T being non empty TopStruct, t1,t2 being Point of T
  for p being Path of t1,t2
  holds inf dom p = 0 & sup dom p = 1
  proof
    let T be non empty TopStruct;
    let t1,t2 be Point of T;
    let p be Path of t1,t2;
    [.0,1.] = dom p by BORSUK_1:40,FUNCT_2:def 1;
    hence thesis by XXREAL_2:25,29;
  end;
