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We study graphs with the property that every edge-colouring admits a monochromatic cycle (the length of which may depend freely on the colouring) and describe those graphs that are minimal with this property. We show that every member in…

Combinatorics · Mathematics 2018-08-01 Damian Reding , Anusch Taraz

We create a framework for hereditary graph classes $\mathcal{G}^\delta$ built on a two-dimensional grid of vertices and edge sets defined by a triple $\delta=\{\alpha,\beta,\gamma\}$ of objects that define edges between consecutive columns,…

Combinatorics · Mathematics 2023-11-01 Robert Brignall , Daniel Cocks

We show that every NP problem is polynomially equivalent to a simple combinatorial problem: the membership problem for a special class of digraphs. These classes are defined by means of shadows (projections) and by finitely many forbidden…

Computational Complexity · Computer Science 2007-06-27 Gabor Kun , Jaroslav Nesetril

The class of cographs is known to have unbounded linear clique-width. We prove that a hereditary class of cographs has bounded linear clique-width if and only if it does not contain all quasi-threshold graphs or their complements. The proof…

Combinatorics · Mathematics 2016-01-26 Robert Brignall , Nicholas Korpelainen , Vincent Vatter

Given a matroid together with a coloring of its ground set, a subset of its elements is called rainbow colored if no two of its elements have the same color. We show that if a binary matroid of rank $r$ is colored with exactly $r$ colors,…

Combinatorics · Mathematics 2021-09-02 Kristóf Bérczi , Tamás Schwarcz

This paper studies the structure of graphs with given tree-width and excluding a fixed complete bipartite subgraph, which generalises the bounded degree setting. We give a new structural description of such graphs in terms of so-called…

Combinatorics · Mathematics 2025-12-15 Chun-Hung Liu , David R. Wood

A graph coloring has bounded clustering if each monochromatic component has bounded size. Equivalently, it is a partition of the vertices into induced subgraphs with bounded size components. This paper studies clustered colorings of graphs,…

Combinatorics · Mathematics 2021-12-07 Chun-Hung Liu , David R. Wood

The model theory based notion of the first order convergence unifies the notions of the left-convergence for dense structures and the Benjamini-Schramm convergence for sparse structures. It is known that every first order convergent…

Combinatorics · Mathematics 2016-08-16 Frantisek Kardos , Daniel Kral , Anita Liebenau , Lukas Mach

An ordering of the vertices of a graph is \emph{connected} if every vertex (but the first) has a neighbor among its predecessors. The greedy colouring algorithm of a graph with a connected order consists in taking the vertices in order, and…

Discrete Mathematics · Computer Science 2018-06-08 Ngoc Khang Le , Nicolas Trotignon

For two graphs S and T, the constrained Ramsey number f(S, T) is the minimum n such that every edge coloring of the complete graph on n vertices, with any number of colors, has a monochromatic subgraph isomorphic to S or a rainbow (all…

Combinatorics · Mathematics 2011-11-10 Po-Shen Loh , Benny Sudakov

In this paper we extend the theory of bidimensionality to two families of graphs that do not exclude fixed minors: map graphs and power graphs. In both cases we prove a polynomial relation between the treewidth of a graph in the family and…

Discrete Mathematics · Computer Science 2007-05-23 Erik D. Demaine , MohammadTaghi Hajiaghayi

We prove that every graph of rank-width $k$ is a pivot-minor of a graph of tree-width at most $2k$. We also prove that graphs of rank-width at most 1, equivalently distance-hereditary graphs, are exactly vertex-minors of trees, and graphs…

Combinatorics · Mathematics 2014-03-26 O-joung Kwon , Sang-il Oum

A connected dominating set in a graph is a dominating set of vertices that induces a connected subgraph. Following analogous studies in the literature related to independent sets, dominating sets, and total dominating sets, we study in this…

Combinatorics · Mathematics 2018-06-12 Nina Chiarelli , Martin Milanič

Structural graph parameters, such as treewidth, pathwidth, and clique-width, are a central topic of study in parameterized complexity. A main aim of research in this area is to understand the "price of generality" of these widths: as we…

Data Structures and Algorithms · Computer Science 2022-04-19 Rémy Belmonte , Eun Jung Kim , Michael Lampis , Valia Mitsou , Yota Otachi

We propose to study transformations on graphs, and more generally structures, by looking at how the cut-rank (as introduced by Oum) of subsets is affected when going from the input structure to the output structure. We consider…

Logic in Computer Science · Computer Science 2024-01-25 Mikołaj Bojańczyk , Pierre Ohlmann

Frick and Grohe [J. ACM 48 (2006), 1184-1206] introduced a notion of graph classes with locally bounded tree-width and established that every first order logic property can be decided in almost linear time in such a graph class. Here, we…

Data Structures and Algorithms · Computer Science 2011-08-30 Tomas Gavenciak , Daniel Kral , Sang-il Oum

Rank-width is a width parameter of graphs describing whether it is possible to decompose a graph into a tree-like structure by `simple' cuts. This survey aims to summarize known algorithmic and structural results on rank-width of graphs.

Combinatorics · Mathematics 2018-05-16 Sang-il Oum

A long-standing conjecture asserts that there exists a constant $c>0$ such that every graph of order $n$ without isolated vertices contains an induced subgraph of order at least $cn$ with all degrees odd. Scott (1992) proved that every…

Combinatorics · Mathematics 2017-07-18 Xinmin Hou , Lei Yu , Jiaao Li , Boyuan Liu

We study graph classes modeled by families of non-crossing (NC) connected sets. Two classic graph classes in this context are disk graphs and proper interval graphs. We focus on the cases when the sets are paths and the host is a tree…

Discrete Mathematics · Computer Science 2020-08-18 Steven Chaplick

This is the first in a series of two papers dealing with $(2P_3,C_4,C_6)$-free graphs, or equivalently, $(2P_3,\text{even hole})$-free graphs. In this two-paper series, we give a full structural description of $(2P_3,C_4,C_6)$-free graphs…

Combinatorics · Mathematics 2025-11-17 Irena Penev
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