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Related papers: Tight Hamilton cycles in cherry quasirandom $3$-un…

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We study the existence of a directed Hamilton cycle in random digraphs with $m$ edges where we condition on minimum in- and out-degree at least one. Denote such a random graph by $D_{n,m}^{(\delta\geq1)}$. We prove that if $m=\tfrac n2(\log…

Combinatorics · Mathematics 2025-06-17 Colin Cooper , Alan Frieze

We present a tight extremal threshold for the existence of Hamilton cycles in graphs with large minimum degree and without a large ``bipartite hole`` (two disjoint sets of vertices with no edges between them). This result extends Dirac's…

Combinatorics · Mathematics 2016-04-20 Colin McDiarmid , Nikola Yolov

It is a longstanding conjecture that every simple drawing of a complete graph on $n \geq 3$ vertices contains a crossing-free Hamiltonian cycle. We strengthen this conjecture to "there exists a crossing-free Hamiltonian path between each…

Combinatorics · Mathematics 2024-03-05 Oswin Aichholzer , Joachim Orthaber , Birgit Vogtenhuber

We study sufficient conditions for Hamiltonian cycles in hypergraphs, and obtain both Tur\'an- and Dirac-type results. While the Tur\'an-type result gives an exact threshold for the appearance of a Hamiltonian cycle in a hypergraph…

Combinatorics · Mathematics 2011-12-01 Roman Glebov , Yury Person , Wilma Weps

Chen, Faudree, Gould, Jacobson, and Lesniak determined the minimum degree threshold for which a balanced $k$-partite graph has a Hamiltonian cycle. We give an asymptotically tight minimum degree condition for Hamiltonian cycles in arbitrary…

Combinatorics · Mathematics 2019-10-10 Louis DeBiasio , Robert A. Krueger , Dan Pritikin , Eli Thompson

We prove that any $3$-uniform hypergraph whose minimum vertex degree is at least $\left(\frac{5}{9} + o(1) \right)\binom{n}{2}$ admits an almost-spanning tight cycle, that is, a tight cycle leaving $o(n)$ vertices uncovered. The bound on…

Combinatorics · Mathematics 2016-06-20 Oliver Cooley , Richard Mycroft

We use a randomised embedding method to prove that for all \alpha>0 any sufficiently large oriented graph G with minimum in-degree and out-degree \delta^+(G),\delta^-(G)\geq (3/8+\alpha)|G| contains every possible orientation of a Hamilton…

Combinatorics · Mathematics 2009-08-06 Luke Kelly

For $k\ge 2$ and $r\ge 1$ such that $k+r\ge 4$, we prove that, for any $\alpha>0$, there exists $\epsilon>0$ such that the union of an $n$-vertex $k$-graph with minimum codegree $\left(1-\binom{k+r-2}{k-1}^{-1}+\alpha\right)n$ and a…

Combinatorics · Mathematics 2018-02-27 Wiebke Bedenknecht , Jie Han , Yoshiharu Kohayakawa , Guilherme Oliveira Mota

We describe an algorithm for the exhaustive generation of non-isomorphic graphs with a given number $k \ge 0$ of hamiltonian cycles, which is especially efficient for small $k$. Our main findings, combining applications of this algorithm…

Combinatorics · Mathematics 2019-07-16 Jan Goedgebeur , Barbara Meersman , Carol T. Zamfirescu

We prove a new sufficient pair degree condition for tight Hamiltonian cycles in $3$-uniform hypergraphs that (asymptotically) improves the best known pair degree condition due to R\"odl, Ruci\'nski, and Szemer\'edi. For graphs, Chv\'atal…

Combinatorics · Mathematics 2021-02-04 Bjarne Schülke

We describe an algorithm for finding Hamilton cycles in random graphs. Our model is the random graph $G=\gc$. In this model $G$ is drawn uniformly from graphs with vertex set $[n]$, $m$ edges and minimum degree at least three. We focus on…

Combinatorics · Mathematics 2012-10-24 Alan Frieze , Simi Haber

We prove that a random graph $G(n,p)$, with $p$ above the Hamiltonicity threshold, is typically such that for any $r$-colouring of its edges there exists a Hamilton cycle with at least $(2/(r+ 1)-o(1))n$ edges of the same colour. This…

Combinatorics · Mathematics 2021-04-22 Lior Gishboliner , Michael Krivelevich , Peleg Michaeli

We show that the threshold for the random graph $G_{n,p}$ to contain the square of a Hamilton cycle is $p=\frac{1}{\sqrt{n}}$. This improves the previous results of K\"uhn and Osthus and also Nenadov and \v{S}kori\'c. In addition we…

Combinatorics · Mathematics 2017-10-06 Patrick Bennett , Andrzej Dudek , Alan Frieze

In this paper we give an approximate answer to a question of Nash-Williams from 1970: we show that for every \alpha > 0, every sufficiently large graph on n vertices with minimum degree at least (1/2 + \alpha)n contains at least n/8…

Combinatorics · Mathematics 2015-03-13 Demetres Christofides , Daniela Kühn , Deryk Osthus

We show that every 4-uniform hypergraph with $n$ vertices and minimum pair degree at least $(5/9+o(1))n^2/2$ contains a tight Hamiltonian cycle. This degree condition is asymptotically optimal.

The problem of packing Hamilton cycles in random and pseudorandom graphs has been studied extensively. In this paper, we look at the dual question of covering all edges of a graph by Hamilton cycles and prove that if a graph with maximum…

Combinatorics · Mathematics 2011-11-15 Roman Glebov , Michael Krivelevich , Tibor Szabó

In 1999, Katona and Kierstead conjectured that if a $k$-uniform hypergraph $\cal H$ on $n$ vertices has minimum co-degree $\lfloor \frac{n-k+3}{2}\rfloor$, i.e., each set of $k-1$ vertices is contained in at least $\lfloor…

Combinatorics · Mathematics 2022-10-14 Guanwu Liu , Xiaonan Liu

We show that every $k$-uniform hypergraph on $n$ vertices whose minimum $(k-2)$-degree is at least $(5/9+o(1))n^2/2$ contains a Hamiltonian cycle. A construction due to Han and Zhao shows that this minimum degree condition is optimal. The…

Combinatorics · Mathematics 2022-07-08 Joanna Polcyn , Christian Reiher , Vojtěch Rödl , Bjarne Schülke

We study the appearance of powers of Hamilton cycles in pseudorandom graphs, using the following comparatively weak pseudorandomness notion. A graph $G$ is $(\varepsilon,p,k,\ell)$-pseudorandom if for all disjoint $X$ and $Y\subset V(G)$…

Combinatorics · Mathematics 2014-02-07 Peter Allen , Julia Böttcher , Hiep Hàn , Yury Person , Yoshiharu Kohayakawa

It is proved that if $G$ is a $t$-tough graph of order $n$ and minimum degree $\delta$ with $t>1$ then either $G$ has a cycle of length at least $\min\{n,2\delta+4\}$ or $G$ is the Petersen graph.

Combinatorics · Mathematics 2012-03-19 Zh. G. Nikoghosyan