New Sidorenko-type inequalities in tournaments

Fuente: arXiv
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Auteurs principaux: He, Xiaoyu, Mani, Nitya, Nie, Jiaxi, Tung, Nathan, Wei, Fan
Format: Preprint
Publié: 2025
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author He, Xiaoyu
Mani, Nitya
Nie, Jiaxi
Tung, Nathan
Wei, Fan
author_facet He, Xiaoyu
Mani, Nitya
Nie, Jiaxi
Tung, Nathan
Wei, Fan
contents As a directed analog of Sidorenko's conjecture in extremal graph theory, Fox, Himwich, Zhou, and the second author defined an oriented graph $H$ to be tournament Sidorenko (anti-Sidorenko) if the random tournament asymptotically minimizes (maximizes) the number of copies of $H$ among all tournaments. We prove new inequalities of this form for oriented trees and cycles, considering both local and global notions of the Sidorenko property. We make progress on a conjecture of the aforementioned authors that every tree has an anti-Sidorenko direction, and give a characterization of short paths. For long paths we show that orientations are split symmetrically between being locally Sidorenko and anti-Sidorenko, yet almost all orientations are not globally Sidorenko. Finally, we give algorithms characterizing the local Sidorenko status of paths and cycles when the number of vertices is not divisible by four.
format Preprint
id arxiv_https___arxiv_org_abs_2512_11222
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle New Sidorenko-type inequalities in tournaments
He, Xiaoyu
Mani, Nitya
Nie, Jiaxi
Tung, Nathan
Wei, Fan
Combinatorics
As a directed analog of Sidorenko's conjecture in extremal graph theory, Fox, Himwich, Zhou, and the second author defined an oriented graph $H$ to be tournament Sidorenko (anti-Sidorenko) if the random tournament asymptotically minimizes (maximizes) the number of copies of $H$ among all tournaments. We prove new inequalities of this form for oriented trees and cycles, considering both local and global notions of the Sidorenko property. We make progress on a conjecture of the aforementioned authors that every tree has an anti-Sidorenko direction, and give a characterization of short paths. For long paths we show that orientations are split symmetrically between being locally Sidorenko and anti-Sidorenko, yet almost all orientations are not globally Sidorenko. Finally, we give algorithms characterizing the local Sidorenko status of paths and cycles when the number of vertices is not divisible by four.
title New Sidorenko-type inequalities in tournaments
topic Combinatorics
url https://arxiv.org/abs/2512.11222