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Related papers: Cycle lengths in randomly perturbed graphs

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We show that for any $d\ge 2$ and $\Delta>0$ there exists $\eta>0$ such that the following holds: Let $G$ be an $n$-vertex graph with at least $\Omega(n^2)$ edges and let $H$ be an $n$-vertex $d$-degenerate graph with maximum degree at most…

Combinatorics · Mathematics 2026-02-26 Jie Han , Seonghyuk Im , Bin Wang , Junxue Zhang

Consider the random subgraph process on a base graph $G$ with $n$ vertices: we generate a sequence $\{G_t\}_{t=0}^{|E(G)|}$ by taking a uniformly random ordering of the edges of $G$ and then adding these edges one by one to the empty graph…

Combinatorics · Mathematics 2026-03-06 Yaobin Chen , Yu Chen , Seonghyuk Im , Yiting Wang

We show that for any fixed dense graph G and bounded-degree tree T on the same number of vertices, a modest random perturbation of G will typically contain a copy of T . This combines the viewpoints of the well-studied problems of embedding…

Combinatorics · Mathematics 2025-05-30 Michael Krivelevich , Matthew Kwan , Benny Sudakov

For a positive constant $\alpha$ a graph $G$ on $n$ vertices is called an $\alpha$-expander if every vertex set $U$ of size at most $n/2$ has an external neighborhood whose size is at least $\alpha\left|U\right|$. We study cycle lengths in…

Combinatorics · Mathematics 2020-06-09 Limor Friedman , Michael Krivelevich

In an $r$-uniform hypergraph on $n$ vertices a tight Hamilton cycle consists of $n$ edges such that there exists a cyclic ordering of the vertices where the edges correspond to consecutive segments of $r$ vertices. We provide a first…

Combinatorics · Mathematics 2021-07-01 Peter Allen , Christoph Koch , Olaf Parczyk , Yury Person

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

Random hyperbolic graphs were recently introduced by Krioukov et. al. [KPKVB10] as a model for large networks. Gugelmann, Panagiotou, and Peter [GPP12] then initiated the rigorous study of random hyperbolic graphs using the following model:…

Combinatorics · Mathematics 2014-11-25 Marcos Kiwi , Dieter Mitsche

Let $G$ be a graph attaining the maximum spectral radius among all connected nonregular graphs of order $n$ with maximum degree $\Delta$. Let $\lambda_1(G)$ be the spectral radius of $G$. A nice conjecture due to Liu, Shen and Wang [On the…

Combinatorics · Mathematics 2022-03-25 Lele Liu

For an oriented graph $G$, the oriented discrepancy problem concerns the existence of a spanning subgraph of $G$ with a large imbalance between its forward and backward edge orientations. Freschi and Lo proved the Dirac-type Hamilton cycle…

Combinatorics · Mathematics 2026-05-21 Yufei Chang , Yangyang Cheng , Zhilan Wang , Shuo Wei , Jin Yan

A graph on n vertices is called pancyclic if it contains a cycle of length l for all 3 \le l \le n. In 1972, Erdos proved that if G is a Hamiltonian graph on n > 4k^4 vertices with independence number k, then G is pancyclic. He then…

Combinatorics · Mathematics 2011-11-09 Choongbum Lee , Benny Sudakov

We generalize the random graph evolution process of Bohman, Frieze, and Wormald [T. Bohman, A. Frieze, and N. C. Wormald, Random Struct. Algorithms, 25, 432 (2004)]. Potential edges, sampled uniformly at random from the complete graph, are…

Disordered Systems and Neural Networks · Physics 2011-03-31 Wei Chen , Raissa M. D'Souza

We introduce a new technique for bounding the cover time of random walks by relating it to the runtime of randomized broadcast. In particular, we strongly confirm for dense graphs the intuition of Chandra et al. \cite{CRRST97} that "the…

Data Structures and Algorithms · Computer Science 2009-02-11 Robert Elsässer , Thomas Sauerwald

We study the existence of powers of Hamiltonian cycles in graphs with large minimum degree to which some additional edges have been added in a random manner. It follows from the theorems of Dirac and of Koml\'os, Sark\"ozy, and Szemer\'edi…

Combinatorics · Mathematics 2020-05-26 Andrzej Dudek , Christian Reiher , Andrzej Ruciński , Mathias Schacht

For $0\leq \ell <k$, a Hamiltonian $\ell$-cycle in a $k$-uniform hypergraph $H$ is a cyclic ordering of the vertices of $H$ in which the edges are segments of length $k$ and every two consecutive edges overlap in exactly $\ell$ vertices. We…

Combinatorics · Mathematics 2021-11-01 Asaf Ferber , Liam Hardiman , Adva Mond

We show that there exist constants $\delta_1,\delta_2>0$ such that if $G$ is an $(n,d,\lambda)$-graph with $\lambda/d\le\delta_1$, then $G$ contains an induced cycle of length at least $\delta_2n/d$. We further demonstrate that, up to a…

Combinatorics · Mathematics 2025-05-30 Sahar Diskin , Michael Krivelevich , Itay Markbreit , Maksim Zhukovskii

It is known that for $\Omega \subset \mathbb{R}^{2}$ an unbounded convex domain and $H>0$, there exists a graph $G\subset \mathbb{R}^{3}$ of constant mean curvature $H$ over $\Omega $ with $\partial G=$ $\partial \Omega $ if and only if…

Differential Geometry · Mathematics 2020-01-24 Ari J. Aiolfi , Patrícia Klaser

We investigate the existence of a rainbow Hamilton cycle in a uniformly edge-coloured randomly perturbed digraph. We show that for every $\delta \in (0,1)$ there exists $C = C(\delta) > 0$ such that the following holds. Let $D_0$ be an…

Combinatorics · Mathematics 2024-11-20 Kyriakos Katsamaktsis , Shoham Letzter , Amedeo Sgueglia

The main paradigm of smoothed analysis on graphs suggests that for any large graph $G$ in a certain class of graphs, perturbing slightly the edges of $G$ at random (usually adding few random edges to $G$) typically results in a graph having…

Combinatorics · Mathematics 2015-08-13 Michael Krivelevich , Daniel Reichman , Wojciech Samotij

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 show that for each \alpha>0 every sufficiently large oriented graph G with \delta^+(G),\delta^-(G)\ge 3|G|/8+ \alpha |G| contains a Hamilton cycle. This gives an approximate solution to a problem of Thomassen. In fact, we prove the…

Combinatorics · Mathematics 2009-09-29 Luke Kelly , Daniela Kühn , Deryk Osthus