The $2$-torsion of determinantal hypertrees is not Cohen-Lenstra

Fuente: arXiv
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Main Author: Mészáros, András
Format: Preprint
Published: 2024
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author Mészáros, András
author_facet Mészáros, András
contents Let $T_n$ be a $2$-dimensional determinantal hypertree on $n$ vertices. Kahle and Newman conjectured that the $p$-torsion of $H_1(T_n,\mathbb{Z})$ asymptotically follows the Cohen-Lenstra distribution. For $p=2$, we disprove this conjecture by showing that given a positive integer $h$, for all large enough $n$, we have \[\mathbb{P}(\dim H_1(T_n,\mathbb{F}_2)\ge h)\ge \frac{e^{-200h}}{(100h)^{5h}}.\] We also show that $T_n$ is a bad cosystolic expander with positive probability.
format Preprint
id arxiv_https___arxiv_org_abs_2404_02308
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The $2$-torsion of determinantal hypertrees is not Cohen-Lenstra
Mészáros, András
Combinatorics
Probability
Let $T_n$ be a $2$-dimensional determinantal hypertree on $n$ vertices. Kahle and Newman conjectured that the $p$-torsion of $H_1(T_n,\mathbb{Z})$ asymptotically follows the Cohen-Lenstra distribution. For $p=2$, we disprove this conjecture by showing that given a positive integer $h$, for all large enough $n$, we have \[\mathbb{P}(\dim H_1(T_n,\mathbb{F}_2)\ge h)\ge \frac{e^{-200h}}{(100h)^{5h}}.\] We also show that $T_n$ is a bad cosystolic expander with positive probability.
title The $2$-torsion of determinantal hypertrees is not Cohen-Lenstra
topic Combinatorics
Probability
url https://arxiv.org/abs/2404.02308