Irreducibility, Smoothness, and Connectivity of Realization Spaces of Matroids and Hyperplane Arrangements

Fuente: arXiv
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Main Authors: Liwski, Emiliano, Mohammadi, Fatemeh
Format: Preprint
Published: 2024
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author Liwski, Emiliano
Mohammadi, Fatemeh
author_facet Liwski, Emiliano
Mohammadi, Fatemeh
contents We study the realization spaces of matroids and hyperplane arrangements. First, we define the notion of naive dimension for the realization space of matroids and compare it with the expected dimension and the algebraic dimension, exploring the conditions under which these dimensions coincide. Next, we introduce the family of inductively connected matroids and investigate their realization spaces, establishing that they are smooth, irreducible, and isomorphic to a Zariski open subset of a complex space with a known dimension. Furthermore, we present an explicit procedure for computing their defining equations. As corollaries, we identify families of hyperplane arrangements whose moduli spaces are connected. Finally, we apply our results to study the rigidity of matroids. Rigidity, which involves matroids with a unique realization under projective transformations, is key to understanding the connectivity of the moduli spaces of the corresponding hyperplane arrangements.
format Preprint
id arxiv_https___arxiv_org_abs_2410_22175
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Irreducibility, Smoothness, and Connectivity of Realization Spaces of Matroids and Hyperplane Arrangements
Liwski, Emiliano
Mohammadi, Fatemeh
Combinatorics
Commutative Algebra
Algebraic Geometry
We study the realization spaces of matroids and hyperplane arrangements. First, we define the notion of naive dimension for the realization space of matroids and compare it with the expected dimension and the algebraic dimension, exploring the conditions under which these dimensions coincide. Next, we introduce the family of inductively connected matroids and investigate their realization spaces, establishing that they are smooth, irreducible, and isomorphic to a Zariski open subset of a complex space with a known dimension. Furthermore, we present an explicit procedure for computing their defining equations. As corollaries, we identify families of hyperplane arrangements whose moduli spaces are connected. Finally, we apply our results to study the rigidity of matroids. Rigidity, which involves matroids with a unique realization under projective transformations, is key to understanding the connectivity of the moduli spaces of the corresponding hyperplane arrangements.
title Irreducibility, Smoothness, and Connectivity of Realization Spaces of Matroids and Hyperplane Arrangements
topic Combinatorics
Commutative Algebra
Algebraic Geometry
url https://arxiv.org/abs/2410.22175