
theorem
  for P,Q,R being Element of real_projective_plane st P,Q,R are_collinear holds
  Q,R,P are_collinear & R,P,Q are_collinear &
  P,R,Q are_collinear & R,Q,P are_collinear &
  Q,P,R are_collinear by ANPROJ_2:24;
