FROM PLANAR NEARRINGS TO GENERATING BLOCKS

Abstract

Planar nearrings, like most of the subjects in finite geometries, can be applied for the construction of block designs. In this article we introduce the ideas of constructing simple BIBDs (balanced incomplete block designs) from field-generated (or nearfield-generated) planar nearrings. Further investigation reveals that there are strong connections between these kinds of constructions and the action of a sharply 2-transitive group on a set. We next explore the structures of the constructions. The theory is derived from finite fields directly. The main point is on finding a subset $S$ (called generating block) of the field $F$ with respect to the given stabilizer $Stab_{F^*}(S)$. A big portion of simple BIBDs with various parameters can be obtained in this way; many simple BIBDs with the same parameters appear. We classify the constructed BIBDs according to the types of the respective generating blocks.