
theorem Th61:
  for P being Element of BK_model holds
  P is non point_at_infty Element of ProjectiveSpace TOP-REAL 3
  proof
    let P be Element of BK_model;
    reconsider p = P as Element of ProjectiveSpace TOP-REAL 3;
    consider u be Element of TOP-REAL 3 such that
    P1: u is not zero and
    P2: p = Dir u by ANPROJ_1:26;
    u.3 <> 0 by P1,P2,BKMODEL2:2;
    then u`3 <> 0 by EUCLID_5:def 3;
    hence thesis by P1,P2,Th40;
  end;
