Entropy Bounds for Perfect Matchings in Bipartite Hypergraphs

Fuente: arXiv
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Main Authors: Dai, Tantan, Divoux, Alexander, Kelly, Tom
Format: Preprint
Published: 2025
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author Dai, Tantan
Divoux, Alexander
Kelly, Tom
author_facet Dai, Tantan
Divoux, Alexander
Kelly, Tom
contents A hypergraph is \textit{bipartite with bipartition $(A, B)$} if every edge has exactly one vertex in $A$, and a matching in such a hypergraph is \textit{$A$-perfect} if it saturates every vertex in $A$. We prove an upper bound on the number of $A$-perfect matchings in uniform hypergraphs with small maximum codegree. Using this result, we prove that there exist order-$n$ Latin squares with at most $(n/e^{2.117})^n$ transversals when $n$ is odd and $n \equiv 0\pmod 3$. We also show that $k$-uniform $D$-regular hypergraphs on $n$ vertices have at most $((1+o(1))q/e^k)^{Dn/k}$ proper $q$-edge-colorings when $q = (1+o(1))D$ and the maximum codegree is $o(q)$.
format Preprint
id arxiv_https___arxiv_org_abs_2506_17652
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Entropy Bounds for Perfect Matchings in Bipartite Hypergraphs
Dai, Tantan
Divoux, Alexander
Kelly, Tom
Combinatorics
05D40, 05B15, 05C15
A hypergraph is \textit{bipartite with bipartition $(A, B)$} if every edge has exactly one vertex in $A$, and a matching in such a hypergraph is \textit{$A$-perfect} if it saturates every vertex in $A$. We prove an upper bound on the number of $A$-perfect matchings in uniform hypergraphs with small maximum codegree. Using this result, we prove that there exist order-$n$ Latin squares with at most $(n/e^{2.117})^n$ transversals when $n$ is odd and $n \equiv 0\pmod 3$. We also show that $k$-uniform $D$-regular hypergraphs on $n$ vertices have at most $((1+o(1))q/e^k)^{Dn/k}$ proper $q$-edge-colorings when $q = (1+o(1))D$ and the maximum codegree is $o(q)$.
title Entropy Bounds for Perfect Matchings in Bipartite Hypergraphs
topic Combinatorics
05D40, 05B15, 05C15
url https://arxiv.org/abs/2506.17652