SPG-reguli satisfying the polar property and a new semipartial geometry
A semipartial geometry (SPG) spg\((s,t,\alpha,\mu)\) is a partial linear space of order \((s,t)\) satisfying the following axioms: i) if a point \(x\) and a line \(L\) are not incident, then there are \(0\) or \(\alpha\) \((\alpha >0)\) points which are collinear with \(x\) and incident with \(L\); ii) if two points are not collinear, then there are \(\mu\) \((\mu>0)\) points collinear with both. In this nice paper, the authors construct a new semipartial geometry based on a Buekenhout-Metz unital and determine its automorphism group.
scientific article; zbMATH DE number 2091512