
theorem Th09:
  for P,Q being Point of BK-model-Plane holds
  between P,P,Q & between P,Q,Q
  proof
    let P,Q be Point of BK-model-Plane;
    reconsider P2 = BK_to_T2 P,Q2 = BK_to_T2 Q as Point of TarskiEuclid2Space;
    between P2,P2,Q2 by GTARSKI1:17;
    hence between P,P,Q by Th05;
    between P2,Q2,Q2 by GTARSKI1:14;
    hence between P,Q,Q by Th05;
  end;
