English

Non-very generic arrangements in low dimension

Combinatorics 2025-09-23 v2

Abstract

The discriminantal arrangement B(n,k,A)\mathcal{B}(n,k,\mathcal{A}) has been introduced by Manin and Schectman in 1989 and it consists of all non-generic translates of a generic arrangement A\mathcal{A} of n hyperplanes in a kk-dimensional space. It is known that its combinatorics depends on the original arrangement A which, following Bayer and Brandt [3], is called very generic if the intersection lattice of the induced discriminantal arrangement has maximum cardinality, non-very generic otherwise. While a complete description of the combinatorics of B(n,k,A)\mathcal{B}(n,k,\mathcal{A}) when A\mathcal{A} is very generic is known (see [2]), very few is known in the non-very generic case. Even to provide examples of non very generic arrangements proved to be a non-trivial task (see [17]). In this paper, we characterize, classify and provide examples of non-very generic arrangements in low dimension.

Keywords

Cite

@article{arxiv.2202.04794,
  title  = {Non-very generic arrangements in low dimension},
  author = {Takuya Saito and Simona Settepanella},
  journal= {arXiv preprint arXiv:2202.04794},
  year   = {2025}
}
R2 v1 2026-06-24T09:29:20.322Z