Affine polar spaces derived from symplectic spaces, their geometry and   representations: alternating semiforms
  Deleting a hyperplane from a polar space associated with a symplectic polarity we get a specific, symplectic, affine polar space. Similar geometry, called an \afsempol\ arises as a result of generalization of the notion of an alternating form to a semiform. Some properties of these two geometries are given and their automorphism groups are characterized. 
K. Pra\.zmowski, M. \.Zynel
math.MG math.CO