English
Related papers

Related papers: A single $3$-graph with infinite stability number

200 papers

We prove a version of the strong Taylor's conjecture for stable graphs: if $G$ is a stable graph whose chromatic number is strictly greater than $\beth_2(\aleph_0)$ then $G$ contains all finite subgraphs of Sh$_n(\omega)$ and thus has…

Logic · Mathematics 2021-03-26 Yatir Halevi , Itay Kaplan , Saharon Shelah

We prove that, for any finite set of minimal $r$-graph patterns, there is a finite family $\mathcal F$ of forbidden $r$-graphs such that the extremal Tur\'an constructions for $\mathcal F$ are precisely the maximum $r$-graphs obtainable…

Combinatorics · Mathematics 2025-03-12 Xizhi Liu , Oleg Pikhurko

The distinguishing number $D(G)$ of a graph $G$ is the least integer $d$ such that $G$ has a vertex labeling with $d$ labels that is preserved only by a trivial automorphism. The distinguishing stability, of a graph $G$ is denoted by…

Combinatorics · Mathematics 2016-09-26 Saeid Alikhani , Samaneh Soltani

We characterize stability of graph C*-algebras by giving five conditions equivalent to their stability. We also show that if G is a graph with no sources, then C*(G) is stable if and only if each vertex in G can be reached by an infinite…

Operator Algebras · Mathematics 2007-05-23 Mark Tomforde

The stability number of a graph G, denoted by alpha(G), is the cardinality of a stable set of maximum size in G. A graph is well-covered if every maximal stable set has the same size. G is a Koenig-Egervary graph if its order equals…

Combinatorics · Mathematics 2007-05-23 Vadim E. Levit , Eugen Mandrescu

Erd\H{o}s proved an upper bound on the number of edges in an $n$-vertex non-Hamiltonian graph with given minimum degree and showed sharpness via two members of a particular graph family. F\"{u}redi, Kostochka and Luo showed that these two…

Combinatorics · Mathematics 2025-04-03 Zhanar Berikkyzy , Kirsten Hogenson , Rachel Kirsch , Jessica McDonald

We extend the classical stability theorem of Erdos and Simonovits in two directions: first, we allow the order of the forbidden graph to grow as log of order of the host graph, and second, our extremal condition is on the spectral radius of…

Combinatorics · Mathematics 2007-11-26 Vladimir Nikiforov

The $3$-uniform tight $\ell$-cycle minus one edge $C_{\ell}^{3-}$ is the $3$-graph on $\ell$ vertices consisting of $\ell-1$ consecutive triples in the cyclic order. We show that for every integer $\ell \ge 5$ satisfying $\ell\not\equiv…

Combinatorics · Mathematics 2025-07-02 Levente Bodnár , Jinghua Deng , Jianfeng Hou , Xizhi Liu , Hongbin Zhao

Given a family of $r$-uniform hypergraphs ${\cal F}$ (or $r$-graphs for brevity), the Tur\'an number $ex(n,{\cal F})$ of ${\cal F}$ is the maximum number of edges in an $r$-graph on $n$ vertices that does not contain any member of ${\cal…

Combinatorics · Mathematics 2015-10-14 Axel Brandt , David Irwin , Tao Jiang

The Tur\'{a}n number of a graph $H$, $\text{ex}(n,H)$, is the maximum number of edges in an $n$-vertex graph that does not contain $H$ as a subgraph. For a vertex $v$ and a multi-set $\mathcal{F}$ of graphs, the suspension $\mathcal{F}+v$…

Combinatorics · Mathematics 2022-11-16 Jianfeng Hou , Heng Li , Qinghou Zeng

Let $G$ be a connected nonregular graphs of order $n$ with maximum degree $\Delta$ that attains the maximum spectral radius. Liu and Li (2008) proposed a conjecture stating that $G$ has a degree sequence $(\Delta,\ldots,\Delta,\delta)$ with…

Combinatorics · Mathematics 2024-11-27 Zejun Huang , Jiahui Liu , Chenxi Yang

We say that a graph G is $(k,\ell)$-stable if removing $k$ vertices from it reduces its independence number by at most $\ell$. We say that G is tight $(k,\ell)$-stable if it is $(k,\ell)$-stable and its independence number equals…

Combinatorics · Mathematics 2024-02-08 Dingding Dong , Sammy Luo

Recently, Balogh, Kostochka and Liu in [Packing chromatic number of cubic graphs, Discrete Math.~341 (2018) 474--483] answered in negative the question that was posed in several earlier papers whether the packing chromatic number is bounded…

Combinatorics · Mathematics 2018-01-31 Boštjan Brešar , Jasmina Ferme

In this thesis we consider ordered graphs (that is, graphs with a fixed linear ordering on their vertices). We summarize and further investigations on the number of edges an ordered graph may have while avoiding a fixed forbidden ordered…

Discrete Mathematics · Computer Science 2009-07-16 Craig Weidert

An isolating set in a graph is a set $X$ of vertices such that every edge of the graph is incident with a vertex of $X$ or its neighborhood. The isolation number of a graph, or equivalently the vertex-edge domination number, is the minimum…

Combinatorics · Mathematics 2024-05-22 Geoffrey Boyer , Wayne Goddard

We study deterministic constructions of graphs for which the unique completion of low rank matrices is generically possible regardless of the values of the entries. We relate the completability to the presence of some patterns (particular…

Information Theory · Computer Science 2026-01-01 Augustin Cosse

The obstruction set for graphs with knotless embeddings is not known, but a recent paper of Goldberg, Mattman, and Naimi indicates that it is quite large. Almost all known obstructions fall into four Triangle-Y families and they ask if…

Combinatorics · Mathematics 2023-01-25 Danielle Gregg , Thomas W. Mattman , Zachary Porat , George Todd

Let G be a finite graph with the non-k-order property (essentially, a uniform finite bound on the size of an induced sub-half-graph). A major result of the paper applies model-theoretic arguments to obtain a stronger version of…

Logic · Mathematics 2015-08-20 M. Malliaris , S. Shelah

Understanding which system structure can sustain stable dynamics is a fundamental step in the design and analysis of large scale dynamical systems. Towards this goal, we investigate here the structural stability of systems with a random…

Combinatorics · Mathematics 2020-03-26 Mohamed Ali Belabbas , Artur Kirkoryan

It follows from known results that every regular tripartite hypergraph of positive degree, with $n$ vertices in each class, has matching number at least $n/2$. This bound is best possible, and the extremal configuration is unique. Here we…

Combinatorics · Mathematics 2017-01-24 Penny Haxell , Lothar Narins