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The aim of this paper is to generalize the notion of the coloring complex of a graph to hypergraphs. We present three different interpretations of those complexes -- a purely combinatorial one and two geometric ones. It is shown, that most…

Combinatorics · Mathematics 2012-05-01 Felix Breuer , Aaron Dall , Martina Kubitzke

A graph G is a homomorphic preimage of another graph H, or equivalently G is H-colorable, if there exists a graph homomorphism from G to H. A classic problem is to characterize the family of homomorphic preimages of a given graph H. A…

Combinatorics · Mathematics 2024-06-13 Sally Cockburn

The $k$-Coloring problem on hereditary graph classes has been a deeply researched problem over the last decade. A hereditary graph class is characterized by a (possibly infinite) list of minimal forbidden induced subgraphs. We say that a…

Computational Complexity · Computer Science 2025-09-03 Justyna Jaworska , Bartłomiej Kielak , Tomáš Masařík , Jana Masaříková

The bounds on the sum and product of chromatic numbers of a graph and its complement are known as Nordhaus-Gaddum inequalities. In this paper, we study the operations on the Independence numbers of graphs with their complement. We also…

Combinatorics · Mathematics 2015-06-11 Susanth C , Sunny Joseph Kalayathankal

Recently, the theory of dense graph limits has received attention from multiple disciplines including graph theory, computer science, statistical physics, probability, statistics, and group theory. In this paper we initiate the study of the…

Combinatorics · Mathematics 2015-03-09 Peter Diao , Dominique Guillot , Apoorva Khare , Bala Rajaratnam

A graph is $(H_1,H_2)$-free for a pair of graphs $H_1,H_2$ if it contains no induced subgraph isomorphic to $H_1$ or $H_2$. In 2001, Kr\'al', Kratochv\'{\i}l, Tuza, and Woeginger initiated a study into the complexity of Colouring for…

Data Structures and Algorithms · Computer Science 2017-06-08 Alexandre Blanché , Konrad K. Dabrowski , Matthew Johnson , Daniël Paulusma

Let $G=(V(G), E(G))$ be an undirected graph with a measure function $\mu$ assigning non-negative values to subgraphs $H$ so that $\mu(H)$ does not exceed the clique cover number of $H$. When $\mu$ satisfies some additional natural…

Computational Geometry · Computer Science 2015-04-21 Farhad Shahrokhi

A 2-edge-colored graph or a signed graph is a simple graph with two types of edges. A homomorphism from a 2-edge-colored graph $G$ to a 2-edge-colored graph $H$ is a mapping $\varphi: V(G) \rightarrow V(H)$ that maps every edge in $G$ to an…

Combinatorics · Mathematics 2020-09-14 Christopher Duffy , Fabien Jacques , Mickael Montassier , Alexandre Pinlou

Functionality ($\mathrm{fun}$) is a graph parameter that generalizes graph degeneracy defined by Alecu et al. [JCTB, 2021]. They research the relation of functionality to many other graphs parameters (tree-width, clique-width, VC-dimension,…

Combinatorics · Mathematics 2025-06-02 Pavel Dvořák , Lukáš Folwarczný , Michal Opler , Pavel Pudlák , Robert Šámal , Tung Anh Vu

For a class $\mathcal{H}$ of graphs, #Sub$(\mathcal{H})$ is the counting problem that, given a graph $H\in \mathcal{H}$ and an arbitrary graph $G$, asks for the number of subgraphs of $G$ isomorphic to $H$. It is known that if $\mathcal{H}$…

Computational Complexity · Computer Science 2014-07-11 Radu Curticapean , Dániel Marx

The Grundy number of a graph $G$ is the maximum number of colors used by the First-Fit coloring of $G$ and is denoted by $\Gamma(G)$. Similarly, the ${\rm b}$-chromatic number ${\rm{b}}(G)$ of $G$ expresses the worst case behavior of…

Combinatorics · Mathematics 2020-04-01 Manouchehr Zaker

The boxicity (respectively cubicity) of a graph $G$ is the minimum non-negative integer $k$, such that $G$ can be represented as an intersection graph of axis-parallel $k$-dimensional boxes (respectively $k$-dimensional unit cubes) and is…

Combinatorics · Mathematics 2014-04-30 L. Sunil Chandran , Rogers Mathew , Deepak Rajendraprasad

An edge-coloring of a graph $G$ with consecutive integers $c_{1},\ldots,c_{t}$ is called an \emph{interval $t$-coloring} if all colors are used, and the colors of edges incident to any vertex of $G$ are distinct and form an interval of…

Combinatorics · Mathematics 2015-08-04 Petros A. Petrosyan , Hayk H. Tepanyan

Let $G$ be a graph of order $n$. A classical upper bound for the domination number of a graph $G$ having no isolated vertices is $\lfloor\frac{n}{2}\rfloor$. However, for several families of graphs, we have $\gamma(G) \le…

Combinatorics · Mathematics 2025-12-09 Subramanian Arumugam , Suresh Manjanath Hegde , Shashanka Kulamarva

The independent domination number of a finite graph G is the minimum cardinality of an independent dominating set of vertices. The independent bondage number of G is the minimum cardinality of a set of edges whose deletion results in a…

Combinatorics · Mathematics 2024-02-06 E. G. K. M. Gamlath , Bing Wei , Talmage James Reid

For a simple graph $G$, denote by $n$, $\Delta(G)$, and $\chi'(G)$ its order, maximum degree, and chromatic index, respectively. A connected class 2 graph $G$ is edge-chromatic critical if $\chi'(G-e)<\Delta(G)+1$ for every edge $e$ of $G$.…

Combinatorics · Mathematics 2021-03-10 Yan Cao , Guantao Chen , Songling Shan

It is known that every proper minor-closed class of graphs has bounded stack-number (a.k.a. book thickness and page number). While this includes notable graph families such as planar graphs and graphs of bounded genus, many other graph…

Computational Geometry · Computer Science 2016-08-24 Vida Dujmović , Fabrizio Frati

For any particular class of graphs, algorithms for computational problems restricted to the class often rely on structural properties that depend on the specific problem at hand. This begs the question if a large set of such results can be…

A domination-based identification problem on a graph $G$ is one where the objective is to choose a subset $C$ of the vertex set of $G$ such that $C$ has both, a domination property, that is, $C$ is either a dominating or a total-dominating…

Combinatorics · Mathematics 2025-10-14 Dipayan Chakraborty , Annegret K. Wagler

For a graph $G$, the set of vertices in $G$ is denoted by $V(G)$, and the set of edges in $G$ is denoted by $E(G)$. A fractional $[a,b]$-factor of a graph $G$ is a function $h$ from $E(G)$ to $[0,1]$ satisfying $a\leq d_G^{h}(v)\leq b$ for…

Combinatorics · Mathematics 2020-01-01 Sizhong Zhou , Quanru Pan