Powers of Hamiltonian cycles in randomly augmented Pósa-Seymour graphs

Fuente: arXiv
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Main Authors: Antoniuk, Sylwia, Dudek, Andrzej, Ruciński, Andrzej
Format: Preprint
Published: 2025
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author Antoniuk, Sylwia
Dudek, Andrzej
Ruciński, Andrzej
author_facet Antoniuk, Sylwia
Dudek, Andrzej
Ruciński, Andrzej
contents We study the question of the least number of random edges that need to be added to a Pósa-Seymour graph, that is, a graph with minimum degree exceeding $\frac k{k+1}n$, to secure the existence of the $m$-th power of a Hamiltonian cycle, $m>k$. It turns out that, depending on $k$ and $m$, this quantity may be captured by two types of thresholds, with one of them, called over-threshold, becoming dominant for large $m$. Indeed, for each $k\ge2$ and $m>m_0(k)$, we establish asymptotically tight lower and upper bounds on the over-thresholds (provided they exist) and show that for infinitely many instances of $m$ the two bounds coincide. In addition, we also determine the thresholds for some small values of $k$ and $m$.
format Preprint
id arxiv_https___arxiv_org_abs_2512_23886
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Powers of Hamiltonian cycles in randomly augmented Pósa-Seymour graphs
Antoniuk, Sylwia
Dudek, Andrzej
Ruciński, Andrzej
Combinatorics
We study the question of the least number of random edges that need to be added to a Pósa-Seymour graph, that is, a graph with minimum degree exceeding $\frac k{k+1}n$, to secure the existence of the $m$-th power of a Hamiltonian cycle, $m>k$. It turns out that, depending on $k$ and $m$, this quantity may be captured by two types of thresholds, with one of them, called over-threshold, becoming dominant for large $m$. Indeed, for each $k\ge2$ and $m>m_0(k)$, we establish asymptotically tight lower and upper bounds on the over-thresholds (provided they exist) and show that for infinitely many instances of $m$ the two bounds coincide. In addition, we also determine the thresholds for some small values of $k$ and $m$.
title Powers of Hamiltonian cycles in randomly augmented Pósa-Seymour graphs
topic Combinatorics
url https://arxiv.org/abs/2512.23886