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Related papers: Note on induced paths in sparse random graphs

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We show that for any $d=d(n)$ with $d_0(\epsilon) \le d =o(n)$, with high probability, the size of a largest induced cycle in the random graph $G(n,d/n)$ is $(2\pm \epsilon)\frac{n}{d}\log d$. This settles a long-standing open problem in…

Combinatorics · Mathematics 2022-03-01 Nemanja Draganić , Stefan Glock , Michael Krivelevich

We prove that any bounded degree regular graph with sufficiently strong spectral expansion contains an induced path of linear length. This is the first such result for expanders, strengthening an analogous result in the random setting by…

Combinatorics · Mathematics 2025-03-05 Nemanja Draganić , Peter Keevash

We present a modification of the Depth first search algorithm, suited for finding long induced paths. We use it to give simple proofs of the following results. We show that the induced size-Ramsey number of paths satisfies…

Combinatorics · Mathematics 2022-03-02 Nemanja Draganić , Stefan Glock , Michael Krivelevich

Let $G\sim G(n,p)$ be a (hidden) Erd\H{o}s-R\'enyi random graph with $p=(1+ \varepsilon)/n$ for some fixed constant $ \varepsilon >0$. Ferber, Krivelevich, Sudakov, and Vieira showed that to reveal a path of length…

Combinatorics · Mathematics 2024-09-05 Vesna Iršič , Julien Portier , Leo Versteegen

Given a large graph $H$, does the binomial random graph $G(n,p)$ contain a copy of $H$ as an induced subgraph with high probability? This classical question has been studied extensively for various graphs $H$, going back to the study of the…

Combinatorics · Mathematics 2020-11-17 Oliver Cooley , Nemanja Draganić , Mihyun Kang , Benny Sudakov

In 2012, Ne\v{s}et\v{r}il and Ossona de Mendez proved that graphs of bounded degeneracy that have a path of order $n$ also have an induced path of order $\Omega(\log \log n)$. In this paper we give an almost matching upper bound by…

Combinatorics · Mathematics 2026-02-13 Basile Couëtoux , Oscar Defrain , Jean-Florent Raymond

Consider a graph $G$ with a path $P$ of order $n$. What conditions force $G$ to also have a long induced path? As complete bipartite graphs have long paths but no long induced paths, a natural restriction is to forbid some fixed complete…

Combinatorics · Mathematics 2024-11-14 Julien Duron , Louis Esperet , Jean-Florent Raymond

In an article published in 1987 in Combinatorica \cite{MR918397}, Frieze and Jackson established a lower bound on the length of the longest induced path (and cycle) in a sparse random graph. Their bound is obtained through a rough analysis…

Probability · Mathematics 2021-06-22 Nathanaël Enriquez , Gabriel Faraud , Laurent Ménard , Nathan Noiry

For any $S\subset [n]$, we compute the probability that the subgraph of $\mathcal{G}_{n,d}$ induced by $S$ is a given graph $H$ on the vertex set $S$. The result holds for any $d=o(n^{1/3})$ and is further extended to $\mathcal{G}_{{\bf…

Combinatorics · Mathematics 2010-11-30 Pu Gao , Yi Su , Nicholas Wormald

We prove that every 3-connected planar graph on $n$ vertices contains an induced path on $\Omega(\log n)$ vertices, which is best possible and improves the best known lower bound by a multiplicative factor of $\log \log n$. We deduce that…

Combinatorics · Mathematics 2016-12-20 Louis Esperet , Laetitia Lemoine , Frédéric Maffray

Graphs of bounded degeneracy are known to contain induced paths of order $\Omega(\log \log n)$ when they contain a path of order $n$, as proved by Ne\v{s}et\v{r}il and Ossona de Mendez (2012). In 2016 Esperet, Lemoine, and Maffray…

Combinatorics · Mathematics 2023-12-21 Oscar Defrain , Jean-Florent Raymond

We discuss a new algorithmic type of problem in random graphs studying the minimum number of queries one has to ask about adjacency between pairs of vertices of a random graph $G\sim {\mathcal G}(n,p)$ in order to find a subgraph which…

Combinatorics · Mathematics 2016-08-05 Asaf Ferber , Michael Krivelevich , Benny Sudakov , Pedro Vieira

In this paper we show that every graph of pathwidth less than $k$ that has a path of order $n$ also has an induced path of order at least $\frac{1}{3} n^{1/k}$. This is an exponential improvement and a generalization of the polylogarithmic…

Discrete Mathematics · Computer Science 2023-01-04 Claire Hilaire , Jean-Florent Raymond

More than 40 years ago, Galvin, Rival and Sands showed that every $K_{s, s}$-free graph containing an $n$-vertex path must contain an induced path of length $f(n)$, where $f(n)\to \infty$ as $n\to \infty$. Recently, it was shown by Duron,…

Combinatorics · Mathematics 2025-09-03 Zach Hunter , Aleksa Milojević , Benny Sudakov , István Tomon

For a fixed integer $k\geqslant 2$, let $G\in \mathcal{G}(n,p)$ be a simple connected graph on $n\rightarrow\infty$ vertices with the expected degree $d=np$ satisfying $d\geqslant c$ and $d^{k-1}= o(n)$ for some large enough constant $c$.…

Combinatorics · Mathematics 2022-02-08 Fang Tian , Yun-Qin Sun , Zi-Long Liu

In this paper, we study long paths and Hamiltonian paths in inhomogenous random graphs. In the first part of the paper, we consider an inhomogenous Erd\H{o}s-R\'enyi random graph $G_E$ with average edge density $p_n.$ We prove that if…

Probability · Mathematics 2017-04-18 Ghurumuruhan Ganesan

An induced path factor of a graph $G$ is a set of induced paths in $G$ with the property that every vertex of $G$ is in exactly one of the paths. The induced path number $\rho(G)$ of $G$ is the minimum number of paths in an induced path…

Combinatorics · Mathematics 2021-04-19 Saieed Akbari , Daniel Horsley , Ian M. Wanless

Given an integer $n$, let $G(n)$ be the number of integer sequences $n-1\ge d_1\ge d_2\ge\dotsb\ge d_n\ge 0$ that are the degree sequence of some graph. We show that $G(n)=(c+o(1))4^n/n^{3/4}$ for some constant $c>0$, improving both the…

Combinatorics · Mathematics 2024-09-26 Paul Balister , Serte Donderwinkel , Carla Groenland , Tom Johnston , Alex Scott

Long paths and cycles in sparse random graphs and digraphs were studied intensively in the 1980's. It was finally shown by Frieze in 1986 that the random graph $\cG(n,p)$ with $p=c/n$ has a cycle on at all but at most $(1+\epsilon)ce^{-c}n$…

Combinatorics · Mathematics 2011-02-16 Michael Krivelevich , Eyal Lubetzky , Benny Sudakov

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
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