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A near-linear upper bound for Burr's conjecture
Abstract
Let f(k) denote the smallest integer such that every oriented graph D with chromatic number at least f(k) contains every oriented tree on k vertices. Burr (1980) showed that f(k)≤ (k−1)2 and conjectured that f(k)=2k−2. Bessy, Gonçalves and Reinald (2025) proved that f(k)=O(k3/2). In this paper, by using an absorbing set method, we show that f(k)≤ ⌊ 31log (k!)⌋=O(klog k).
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BibTeX
@misc{fan2026nearlinear,
title = {{A near-linear upper bound for Burr's conjecture}},
author = {Liangdong Fan and Junying Lu and Yaojun Chen},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.18175},
eprint = {2609.18175},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.18175},
}
RIS
TY - UNPB
TI - A near-linear upper bound for Burr's conjecture
AU - Liangdong Fan
AU - Junying Lu
AU - Yaojun Chen
PY - 2026
DA - 2026/09/16
PB - arXiv
DO - 10.48550/arxiv.2609.18175
UR - https://arxiv.org/abs/2609.18175
AB - Let f(k) denote the smallest integer such that every oriented graph D with chromatic number at least f(k) contains every oriented tree on k vertices. Burr (1980) showed that f(k)≤ (k−1)^2 and conjectured that f(k)=2k−2. Bessy, Gonçalves and Reinald (2025) proved that f(k)=O(k^3/2). In this paper, by using an absorbing set method, we show that f(k)≤ ⌊ 31log (k!)⌋=O(klog k).
ER -