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A graph is \emph{well-dominated} if all of its minimal dominating sets have the same cardinality. We prove that at least one of the factors is well-dominated if the Cartesian product of two graphs is well-dominated. In addition, we show…

Combinatorics · Mathematics 2019-09-24 Sarah E. Anderson , Kirsti Kuenzel , Douglas F. Rall

The purposes of this note are the following two; we first generalize Okada-Takeuti's well quasi ordinal diagram theory, utilizing the recent result of Dershowitz-Tzameret's version of tree embedding theorem with gap conditions. Second, we…

Logic in Computer Science · Computer Science 2019-02-07 Mitsuhiro Okada , Yuta Takahashi

Motivated by his work on the classification of countable homogeneous oriented graphs, Cherlin asked about the typical structure of oriented graphs (i) without a transitive triangle, or (ii) without an oriented triangle. We give an answer to…

Combinatorics · Mathematics 2015-12-15 Deryk Osthus , Daniela Kühn , Timothy Townsend , Yi Zhao

The class of quasi-chain graphs is an extension of the well-studied class of chain graphs. This latter class enjoys many nice and important properties, such as bounded clique-width, implicit representation, well-quasi-ordering by induced…

Combinatorics · Mathematics 2021-04-12 Bogdan Alecu , Aistis Atminas , Vadim Lozin , Dmitriy Malyshev

Equistable graphs are graphs admitting positive weights on vertices such that a subset of vertices is a maximal stable set if and only if it is of total weight $1$. In $1994$, Mahadev et al.~introduced a subclass of equistable graphs,…

Combinatorics · Mathematics 2023-10-31 Martin Milanič , Nicolas Trotignon

Recently, Huang gave a very elegant proof of the Sensitivity Conjecture by proving that hypercube graphs have the following property: every induced subgraph on a set of more than half its vertices has maximum degree at least $\sqrt{d}$,…

Combinatorics · Mathematics 2020-05-22 Florian Lehner , Gabriel Verret

In this paper we continue investigations of cover-incomparability graphs of finite partially ordered sets (see \cite{Bres,Bres2,Bres3,Bres4} and \cite{Max,MaxDH}). We consider in some detail the distinction between cover-preserving subsets…

Combinatorics · Mathematics 2018-09-20 Jan Bok , Jana Maxová

We show that a number of conditions on oriented graphs, all of which are satisfied with high probability by randomly oriented graphs, are equivalent. These equivalences are similar to those given by Chung, Graham and Wilson in the case of…

Combinatorics · Mathematics 2011-08-12 Simon Griffiths

A hereditary property of combinatorial structures is a collection of structures (e.g. graphs, posets) which is closed under isomorphism, closed under taking induced substructures (e.g. induced subgraphs), and contains arbitrarily large…

Combinatorics · Mathematics 2007-05-23 József Balogh , Béla Bollobás , Robert Morris

In a digraph, a quasi-kernel is a subset of vertices that is independent and such that the shortest path from every vertex to this subset is of length at most two. The ``small quasi-kernel conjecture,'' proposed by Erd\H{o}s and Sz\'ekely…

Combinatorics · Mathematics 2024-02-27 Hélène Langlois , Frédéric Meunier , Romeo Rizzi , Stéphane Vialette , Yacong Zhou

The competition graph of a directed acyclic graph D is the undirected graph on the same vertex set as D in which two distinct vertices are adjacent if they have a common out-neighbor in D. The competition number of an undirected graph G is…

Combinatorics · Mathematics 2013-10-24 Brendan D. McKay , Pascal Schweitzer , Patrick Schweitzer

An $n$-vertex graph $G$ of edge density $p$ is considered to be quasirandom if it shares several important properties with the random graph $G(n,p)$. A well-known theorem of Chung, Graham and Wilson states that many such `typical'…

Combinatorics · Mathematics 2020-06-17 E. Aigner-Horev , D. Conlon , H. Hàn , Y. Person , M. Schacht

A hereditary property of graphs is a collection of graphs which is closed under taking induced subgraphs. The speed of \P is the function n \mapsto |\P_n|, where \P_n denotes the graphs of order n in \P. It was shown by Alekseev, and by…

Combinatorics · Mathematics 2009-05-13 Noga Alon , Jozsef Balogh , Bela Bollobas , Robert Morris

A graph is well-dominated if all its minimal dominating sets have the same cardinality. In this paper we prove that at least one factor of every connected, well-dominated Cartesian product is a complete graph, which then allows us to give a…

Combinatorics · Mathematics 2023-10-31 Kirsti Kuenzel , Douglas F. Rall

A graph is {\em perfect} if, in all its induced subgraphs, the size of a largest clique is equal to the chromatic number. Examples of perfect graphs include bipartite graphs, line graphs of bipartite graphs and the complements of such…

Combinatorics · Mathematics 2007-05-23 Gérard Cornuéjols

Augustine et al. [DISC 2022] initiated the study of distributed graph algorithms in the presence of Byzantine nodes in the congested clique model. In this model, there is a set $B$ of Byzantine nodes, where $|B|$ is less than a third of the…

Distributed, Parallel, and Cluster Computing · Computer Science 2025-11-03 David Cifuentes-Núñez , Pedro Montealegre , Ivan Rapaport

We collect some general results on graph limits associated to hereditary classes of graphs. As examples, we consider some classes defined by forbidden subgraphs and some classes of intersection graphs, including triangle-free graphs,…

Combinatorics · Mathematics 2013-03-29 Svante Janson

In this paper, we introduce a class of graphs which we call average hereditary graphs. Many graphs that occur in the usual graph theory applications belong to this class of graphs. Many popular types of graphs fall under this class, such as…

Discrete Mathematics · Computer Science 2025-08-11 Syed Mujtaba Hassan , Shahid Hussain

Graph reordering is a powerful technique to increase the locality of the representations of graphs, which can be helpful in several applications. We study how the technique can be used to improve compression of graphs and inverted indexes.…

Data Structures and Algorithms · Computer Science 2017-09-04 Laxman Dhulipala , Igor Kabiljo , Brian Karrer , Giuseppe Ottaviano , Sergey Pupyrev , Alon Shalita

Answering a question of Simonovits and S\' os, Conlon, Fox, and Sudakov proved that for any nonempty graph $H$, and any $\varepsilon>0$, there exists $\delta>0$ polynomial in $\varepsilon$, such that if $G$ is an $n$-vertex graph with the…

Combinatorics · Mathematics 2018-11-28 Xiaoyu He
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