Abstract
It is an open question to give a combinatorial interpretation of the Falk invariant of a hyperplane arrangement, i.e., the third rank of successive quotients in the lower central series of the fundamental group of the arrangement. In this article, we give a combinatorial formula for this invariant in the case of hyperplane arrangements that are complete lift representations of certain gain graphs. As a corollary, we compute the Falk invariant for the cone of the braid, Shi, Linial, and semiorder arrangements.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 751-768 |
| Number of pages | 18 |
| Journal | Discrete and Computational Geometry |
| Volume | 66 |
| Issue number | 2 |
| DOIs | |
| State | Published - Sep 2021 |
| Externally published | Yes |
Keywords
- Falk invariant
- Gain graph
- Hyperplane arrangement
- Lower central series
- Shi arrangement
ASJC Scopus subject areas
- Theoretical Computer Science
- Geometry and Topology
- Discrete Mathematics and Combinatorics
- Computational Theory and Mathematics