Finite groupoids of configurations of lines in ${\mathbb{P}}_{\mathbb{C}}^3$

Abstract

In this paper, we investigate groupoids coming from configurations of lines in three-dimensional space. Given a point and two skew lines in ${\mathbb{P}}_K^3$ over a field $K$, there exists a unique line containing the given point and meeting the two given lines. We use this construction to define a projection function from one line to another by using a skew line as an auxiliary. This way, we may create a groupoid whose objects are lines in a configuration, and whose morphisms are induced by these projection functions. We look at specific configurations for $K=\mathbb{C}$ that yield groupoids with finite automorphism groups.

24 pages, 1 figure. Feedback is appreciated