Dirac's theorem for linear hypergraphs

Fuente: arXiv
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Main Authors: Im, Seonghyuk, Lee, Hyunwoo
Format: Preprint
Published: 2024
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author Im, Seonghyuk
Lee, Hyunwoo
author_facet Im, Seonghyuk
Lee, Hyunwoo
contents Dirac's theorem states that any $n$-vertex graph $G$ with even integer $n$ satisfying $δ(G) \geq n/2$ contains a perfect matching. We generalize this to $k$-uniform linear hypergraphs by proving the following. Any $n$-vertex $k$-uniform linear hypergraph $H$ with minimum degree at least $\frac{n}{k} + Ω(1)$ contains a matching that covers at least $(1-o(1))n$ vertices. This minimum degree condition is asymptotically tight and obtaining a perfect matching is impossible with any degree condition. Furthermore, we show that if $δ(H) \geq (\frac{1}{k}+o(1))n$, then $H$ contains almost spanning linear cycles, almost spanning hypertrees with $o(n)$ leaves, and ``long subdivisions'' of any $o(\sqrt{n})$-vertex graphs.
format Preprint
id arxiv_https___arxiv_org_abs_2403_14269
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Dirac's theorem for linear hypergraphs
Im, Seonghyuk
Lee, Hyunwoo
Combinatorics
Dirac's theorem states that any $n$-vertex graph $G$ with even integer $n$ satisfying $δ(G) \geq n/2$ contains a perfect matching. We generalize this to $k$-uniform linear hypergraphs by proving the following. Any $n$-vertex $k$-uniform linear hypergraph $H$ with minimum degree at least $\frac{n}{k} + Ω(1)$ contains a matching that covers at least $(1-o(1))n$ vertices. This minimum degree condition is asymptotically tight and obtaining a perfect matching is impossible with any degree condition. Furthermore, we show that if $δ(H) \geq (\frac{1}{k}+o(1))n$, then $H$ contains almost spanning linear cycles, almost spanning hypertrees with $o(n)$ leaves, and ``long subdivisions'' of any $o(\sqrt{n})$-vertex graphs.
title Dirac's theorem for linear hypergraphs
topic Combinatorics
url https://arxiv.org/abs/2403.14269