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We show that the independence number of $ G_{n,m}$ is concentrated on two values for $ n^{5/4+ \epsilon} < m \le \binom{n}{2}$. This result establishes a distinction between $G_{n,m}$ and $G_{n,p}$ with $p = m/ \binom{n}{2}$ in the regime $…

Combinatorics · Mathematics 2024-10-10 Tom Bohman , Jakob Hofstad

We show that the domination number of the binomial random graph G_{n,p} with edge-probability p is concentrated on two values for p \ge n^{-2/3+\eps}, and not concentrated on two values for general p \le n^{-2/3}. This refutes a conjecture…

Probability · Mathematics 2024-02-20 Tom Bohman , Lutz Warnke , Emily Zhu

In this note we generalize the results of the recent work by Tom Bohman and Jacob Hofstad on the independence number in G(n, p) to the case of the random k-uniform hypergraph. Concentration in two values occurs in the regime…

Combinatorics · Mathematics 2026-01-01 Stepan Vakhrushev

In this paper we study the behaviour of the domination number of the Erd\H{o}s-R\'enyi random graph $\mathcal{G}(n,p)$. Extending a result of Wieland and Godbole we show that the domination number of $\mathcal{G}(n,p)$ is equal to one of…

Combinatorics · Mathematics 2015-03-17 Roman Glebov , Anita Liebenau , Tibor Szabó

We show that the chromatic number of $G_{n, \frac 12}$ is not concentrated on fewer than $n^{\frac 14 - \varepsilon}$ consecutive values. This addresses a longstanding question raised by Erd\H{o}s and several other authors.

Combinatorics · Mathematics 2021-03-29 Annika Heckel

The size of a largest independent set of vertices in a given graph $G$ is denoted by $\alpha(G)$ and is called its independence number (or stability number). Given a graph $G$ and an integer $K,$ it is NP-complete to decide whether…

Combinatorics · Mathematics 2017-09-11 Ingo Schiermeyer

In this work we show that with high probability the chromatic number of a graph sampled from the random regular graph model $\Gnd$ for $d=o(n^{1/5})$ is concentrated in two consecutive values, thus extending a previous result of Achlioptas…

Combinatorics · Mathematics 2009-07-22 Sonny Ben-Shimon , Michael Krivelevich

An $n$-vertex, $d$-regular graph can have at most $2^{n/2+o_d(n)}$ independent sets. In this paper we address what happens with this upper bound when we impose the further condition that the graph has independence number at most $\alpha$.…

Combinatorics · Mathematics 2024-10-29 David Galvin , Phillip Marmorino

Let $G$ be a simple graph and let $L(G)$ denote the \emph{line graph} of $G$. A \emph{$p$-independent} set in $G$ is a set of vertices $S \subseteq V(G)$ such that the subgraph induced by $S$ has maximum degree at most $p$. The…

Combinatorics · Mathematics 2025-05-12 Yair Caro , Randy Davila , Ryan Pepper

For given graphs $F$ and $G$, the minimum number of edges in an inclusion-maximal $F$-free subgraph of $G$ is called the $F$-saturation number and denoted $\mathrm{sat}(G, F)$. For the star $F=K_{1,r}$, the asymptotics of…

Combinatorics · Mathematics 2022-12-13 Sergej Demyanov , Maksim Zhukovskii

Shamir and Spencer proved in the 1980s that the chromatic number of the binomial random graph G(n,p) is concentrated in an interval of length at most \omega\sqrt{n}, and in the 1990s Alon showed that an interval of length…

Combinatorics · Mathematics 2024-05-22 Erlang Surya , Lutz Warnke

Let $P(n,m)$ be a graph chosen uniformly at random from the class of all planar graphs on vertex set $[n]:=\left\{1, \ldots, n\right\}$ with $m=m(n)$ edges. We show that in the sparse regime, when $m/n\leq 1$, with high probability the…

Combinatorics · Mathematics 2022-05-11 Mihyun Kang , Michael Missethan

We determine the asymptotics of the independence number of the random $d$-regular graph for all $d \ge d_0$. It is highly concentrated, with constant-order fluctuations around $n\alpha_* - c_*\log n$ for explicit constants $\alpha_*(d)$ and…

Probability · Mathematics 2013-10-18 Jian Ding , Allan Sly , Nike Sun

The independence polynomial of a graph is the generating polynomial for the number of independent sets of each size, and its roots are called {\em independence roots}. We investigate the stability of such polynomials, that is, conditions…

Combinatorics · Mathematics 2018-02-08 Jason Brown , Ben Cameron

We investigate the twin-width of the Erd\H{o}s-R\'enyi random graph $G(n,p)$. We unveil a surprising behavior of this parameter by showing the existence of a constant $p^*\approx 0.4$ such that with high probability, when $p^*\le p\le…

Combinatorics · Mathematics 2024-10-23 Jungho Ahn , Debsoumya Chakraborti , Kevin Hendrey , Donggyu Kim , Sang-il Oum

The chromatic number of a very dense random graph $G(n,p)$, with $p \ge 1 - n^{-c}$ for some constant $c > 0$, was first studied by Surya and Warnke, who conjectured that the typical deviation of $\chi(G(n,p))$ from its mean is of order…

Combinatorics · Mathematics 2024-05-27 Zhifei Yan

The independence numbers of powers of graphs have been long studied, under several definitions of graph products, and in particular, under the strong graph product. We show that the series of independence numbers in strong powers of a fixed…

Information Theory · Computer Science 2016-11-17 Noga Alon , Eyal Lubetzky

In this paper, we study the independence polynomial $P_G(x)$ of a finite simple graph $G$, with emphasis on the evaluation at $x=-1$, symmetry, and its connection with the $h$-polynomial of the edge ideal of $G$. For big star graphs, we…

Combinatorics · Mathematics 2026-03-18 Takayuki Hibi , Selvi Kara , Dalena Vien

The celebrated Frieze's result about the independence number of $G(n,p)$ states that it is concentrated in an interval of size $o(1/p)$ for all $C_{\varepsilon}/n<p=o(1)$. We show concentration in an interval of size $o(1/p)$ for the…

Combinatorics · Mathematics 2023-10-23 Margarita Akhmejanova , Vladislav Kozhevnikov

Let $T(G)$ be the size of the largest induced tree of $G$, and let $G_{n,p}$ be the binomial random graph. Kamaldinov, Skorkin, and Zhukovskii proved that $T(G_{n,p})$ equals one of two consecutive values with high probability if $p$ is…

Combinatorics · Mathematics 2026-03-10 Jakob Hofstad
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