ABSTRACT
The planar functions of Dembowski-Ostrom [292] are a potential source for cartesian group planes, planes that are (P, `)-transitive for some flag (P, `), without being semi-translation planes or their duals. However, for rather ‘good’ reasons, the theory has been dormant for many years until the discovery of the spectacular Coulter-Matthews cartesian group planes. We report here on these and related planes.
