
theorem Th25:
  for P1,P2 being Element of absolute st P1 <> P2 holds
  ex P being Element of real_projective_plane st tangent P1 /\ tangent P2 = {P}
  proof
    let P1,P2 be Element of absolute;
    assume P1 <> P2;
    then tangent P1 <> tangent P2 by Th23;
    hence thesis by COLLSP:21,BKMODEL1:76;
  end;
