On the generalized twisted field planes of characteristic 2

Let be a non-Desarguesian semifield plane of order 2 ⁿ 2⁶, and letG be the autotopism group relative to an autotopism triangle . We prove that ifG acts transitively on the non-vertex points on a side of , then is a generalized twisted field plane. A characterization of the generalized twisted field planes of characteristic 2 is also given.Research supported in part by NSF Grants RII-9014056, component IV of the EPSCoR of Puerto Rico grant and ARO grant for Cornell MSI.Research supported in part by NSF Grant No. DMS-9107372.