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We consider the problem of extending partial edge colorings of cartesian products of graphs. More specifically, we suggest the following Evans-type conjecture: If $G$ is a graph where every precoloring of at most $k$ precolored edges can be…

Combinatorics · Mathematics 2023-03-10 Carl Johan Casselgren , Fikre B. Petros , Samuel A. Fufa

We introduce a curvature function for planar graphs to study the connection between the curvature and the geometric and spectral properties of the graph. We show that non-positive curvature implies that the graph is infinite and locally…

Combinatorics · Mathematics 2011-01-18 Matthias Keller

Graphons have traditionally served as limit objects for dense graph sequences, with the cut distance serving as the metric for convergence. However, sparse graph sequences converge to the trivial graphon under the conventional definition of…

Signal Processing · Electrical Eng. & Systems 2023-09-12 Xingchao Jian , Feng Ji , Wee Peng Tay

In this note we consider a more general version of local sparsity introduced recently by Anderson, Kuchukova, and the author. In particular, we say a graph $G = (V, E)$ is $(k, r)$-locally-sparse if for each vertex $v \in V(G)$, the…

Combinatorics · Mathematics 2025-07-22 Abhishek Dhawan

Graph coloring is one of the most famous computational problems with applications in a wide range of areas such as planning and scheduling, resource allocation, and pattern matching. So far coloring problems are mostly studied on static…

Discrete Mathematics · Computer Science 2019-06-12 George B. Mertzios , Hendrik Molter , Viktor Zamaraev

Several algorithmic meta-theorems on kernelization have appeared in the last years, starting with the result of Bodlaender et al. [FOCS 2009] on graphs of bounded genus, then generalized by Fomin et al. [SODA 2010] to graphs excluding a…

Data Structures and Algorithms · Computer Science 2014-11-21 Valentin Garnero , Christophe Paul , Ignasi Sau , Dimitrios M. Thilikos

We prove two distinct and natural refinements of a recent breakthrough result of Molloy (and a follow-up work of Bernshteyn) on the (list) chromatic number of triangle-free graphs. In both our results, we permit the amount of colour made…

Combinatorics · Mathematics 2021-03-05 Ewan Davies , Rémi de Joannis de Verclos , Ross J. Kang , François Pirot

Graph sparsification is a powerful tool to approximate an arbitrary graph and has been used in machine learning over homogeneous graphs. In heterogeneous graphs such as knowledge graphs, however, sparsification has not been systematically…

Machine Learning · Computer Science 2022-11-15 Chandan Chunduru , Chun Jiang Zhu , Blake Gains , Jinbo Bi

We study the strong spatial mixing (decay of correlation) property of proper $q$-colorings of random graph $G(n, d/n)$ with a fixed $d$. The strong spatial mixing of coloring and related models have been extensively studied on graphs with…

Data Structures and Algorithms · Computer Science 2014-02-20 Yitong Yin

For a subset $ S $ of $ \mathbb R^d$, $ S$-graphs are the intersection graphs of specific transformations of $ S $. The class of Burling graphs is a class of triangle-free graphs with arbitrarily large chromatic number that has attracted…

Combinatorics · Mathematics 2023-08-30 Pegah Pournajafi

We revisit the probabilistic construction of sparse random matrices where each column has a fixed number of nonzeros whose row indices are drawn uniformly at random. These matrices have a one-to-one correspondence with the adjacency…

Information Theory · Computer Science 2013-07-25 Bubacarr Bah , Jared Tanner

We analyse properties of geometric intersection graphs to show the strict containment between some natural classes of geometric intersection graphs. In particular, we show the following properties: - A graph $G$ is outerplanar if and only…

Combinatorics · Mathematics 2017-02-02 Sergio Cabello , Miha Jejčič

In this note we elaborate on some notions of surface area for discrete graphs which are closely related to the inverse degree. These notions then naturally lead to associated connectivity measures of graphs and to the definition of a…

Combinatorics · Mathematics 2026-03-09 Patrizio Bifulco , Joachim Kerner

We study the relation between the growth rate of a graph property and the entropy of the graph limits that arise from graphs with that property. In particular, for hereditary classes we obtain a new description of the colouring number,…

Combinatorics · Mathematics 2013-12-20 Hamed Hatami , Svante Janson , Balázs Szegedy

Szemeredi's Regularity Lemma is a very useful tool of extremal combinatorics. Recently, several refinements of this seminal result were obtained for special, more structured classes of graphs. We survey these results in their rich…

Combinatorics · Mathematics 2020-03-31 Yiting Jiang , Jaroslav Nesetril , Patrice Ossona de Mendez , Sebastian Siebertz

We develop an algorithmic framework for graph colouring that reduces the problem to verifying a local probabilistic property of the independent sets. With this we give, for any fixed $k\ge 3$ and $\varepsilon>0$, a randomised…

Data Structures and Algorithms · Computer Science 2020-04-16 Ewan Davies , Ross J. Kang , François Pirot , Jean-Sébastien Sereni

We prove that every class of graphs $\mathscr C$ that is monadically stable and has bounded twin-width can be transduced from some class with bounded sparse twin-width. This generalizes analogous results for classes of bounded linear…

Logic in Computer Science · Computer Science 2022-09-20 Jakub Gajarský , Michał Pilipczuk , Szymon Toruńczyk

An $i$-independent set is a set of vertices whose pairwise distance is at least $i+1$. A proper coloring (resp. a square coloring) of a graph is a partition of its vertices into independent (resp. $2$-independent) sets. A packing…

Combinatorics · Mathematics 2025-09-04 Ilkyoo Choi , Xujun Liu

We consider the graph class Grounded-L corresponding to graphs that admit an intersection representation by L-shaped curves, where additionally the topmost points of each curve are assumed to belong to a common horizontal line. We prove…

Combinatorics · Mathematics 2019-11-06 Vít Jelínek , Martin Töpfer

Square coloring is a variant of graph coloring where vertices within distance two must receive different colors. When considering planar graphs, the most famous conjecture (Wegner, 1977) states that $\frac32\Delta+1$ colors are sufficient…

Combinatorics · Mathematics 2021-12-24 Nicolas Bousquet , Quentin Deschamps , Lucas de Meyer , Théo Pierron