Grassmannians of lines defined in the geometry of a pseudo-polarity
  The regular point-line geometry with respect to a pseudo-polarity is introduced. It is weaker than the underlying metric-projective geometry. The automorphism group of this geometry is determined. This geometry can be also expressed as the geometry of regular lines and planes. 
K. Pra\.zmowski and M. \.Zynel
math.MG math.CO