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In this paper, we make progress on a question related to one of Galvin that has attracted substantial attention recently. The question is that of determining among all graphs $G$ with $n$ vertices and $\Delta(G)\leq r$, which has the most…

Combinatorics · Mathematics 2014-05-07 Jonathan Cutler , A. J. Radcliffe

Frankl and F\"uredi conjectured in 1989 that the maximum Lagrangian of all $r$-uniform hypergraphs of fixed size $m$ is realised by the initial segment of the colexicographic order. In particular, in the principal case $m=\binom{t}{r}$…

Combinatorics · Mathematics 2017-10-11 Mykhaylo Tyomkyn

We prove that if a unimodular random graph is almost surely planar and has finite expected degree, then it has a combinatorial embedding into the plane which is also unimodular. This implies the claim in the title immediately by a theorem…

Probability · Mathematics 2025-02-14 Adam Timar

Motivated by the Erd\H{o}s-Faber-Lov\'asz (EFL) conjecture for hypergraphs, we consider the list edge coloring of linear hypergraphs. We discuss several conjectures for list edge coloring linear hypergraphs that generalize both EFL and…

Combinatorics · Mathematics 2017-01-16 Vance Faber

We present a simple proof for the universality of invariant and equivariant tensorized graph neural networks. Our approach considers a restricted intermediate hypothetical model named Graph Homomorphism Model to reach the universality…

Machine Learning · Computer Science 2019-10-10 Takanori Maehara , Hoang NT

Modern methods of graph theory describe a graph up to isomorphism, which makes it difficult to create mathematical models for visualizing graph drawings on a plane. The topological drawing of the planar part of a graph allows representing…

Combinatorics · Mathematics 2024-08-01 Sergey Kurapov , Maxim Davidovsky

Graphons are analytic objects associated with convergent sequences of graphs. Problems from extremal combinatorics and theoretical computer science led to a study of graphons determined by finitely many subgraph densities, which are…

Combinatorics · Mathematics 2019-03-20 Roman Glebov , Daniel Kral , Jan Volec

We compute the higher topological complexity of ordered configuration spaces of orientable surfaces, thus extending Cohen-Farber's description of the ordinary topological complexity of those spaces.

Algebraic Topology · Mathematics 2016-07-27 Jesús González , Bárbara Gutiérrez

We prove that the total curvature of a planar graph with nonnegative combinatorial curvature is at least $\frac{1}{12}$ if it is positive. Moreover, we classify the metric structures of ambient polygonal surfaces for planar graphs attaining…

Combinatorics · Mathematics 2017-09-18 Bobo Hua , Yanhui Su

A graph is path-pairable if for any pairing of its vertices there exist edge-disjoint paths joining the vertices in each pair. We investigate the behaviour of the maximum degree in path-pairable planar graphs. We show that any $n$-vertex…

Combinatorics · Mathematics 2017-05-18 António Girão , Gábor Mészáros , Kamil Popielarz , Richard Snyder

Here we prove that counting maximum matchings in planar, bipartite graphs is #P-complete. This is somewhat surprising in the light that the number of perfect matchings in planar graphs can be computed in polynomial time. We also prove that…

Computational Complexity · Computer Science 2021-03-09 Istvan Miklos , Miklos Kresz

In this study, we investigate the problem of classifying, characterizing, and designing efficient algorithms for hard inference problems on planar graphs, in the limit of infinite size. The problem is considered hard if, for a deterministic…

Statistics Theory · Mathematics 2016-01-01 Iuliana Teodorescu , Razvan Teodorescu , Pranav Warman

We prove that if the prime graphs in a graph class have bounded lettericity, then the entire class has bounded lettericity if and only if it does not contain arbitrary large matchings, co-matchings, or a family of graphs that we call…

Combinatorics · Mathematics 2021-11-17 Robert Ferguson , Vincent Vatter

We study the uniqueness of optimal solutions to extremal graph theory problems. Lovasz conjectured that every finite feasible set of subgraph density constraints can be extended further by a finite set of density constraints so that the…

Combinatorics · Mathematics 2020-08-26 Andrzej Grzesik , Daniel Král' , László Miklós Lovász

A \emph{queue layout} of a graph consists of a \emph{linear order} of its vertices and a partition of its edges into \emph{queues}, so that no two independent edges of the same queue are nested. The \emph{queue number} of a graph is the…

Data Structures and Algorithms · Computer Science 2019-08-12 Michael A. Bekos , Henry Förster , Martin Gronemann , Tamara Mchedlidze , Fabrizio Montecchiani , Chrysanthi Raftopoulou , Torsten Ueckerdt

In this corrigendum to arXiv:2305.02973, we justify that the motivation behind Conjecture 5.1 is based on a mistaken notion. Moreover, we prove a stronger theorem that disproves the conjecture, and obtain an optimal gradient vector field on…

Combinatorics · Mathematics 2025-05-06 Anupam Mondal , Sajal Mukherjee , Kuldeep Saha

Let $F$ be an $(r+1)$-color critical graph with $r\geq 2$, that is, $\chi(F)=r+1$ and there is an edge $e$ in $F$ such that $\chi(F-e)=r$. Gerbner recently conjectured that every $n$-vertex maximal $F$-free graph with at least…

Combinatorics · Mathematics 2022-05-04 Jian Wang , Shipeng Wang , Weihua Yang

We prove that every 3-connected planar graph on $n$ vertices contains an induced path on $\Omega(\log n)$ vertices, which is best possible and improves the best known lower bound by a multiplicative factor of $\log \log n$. We deduce that…

Combinatorics · Mathematics 2016-12-20 Louis Esperet , Laetitia Lemoine , Frédéric Maffray

In this paper, we study two problems related to planar matchings in random bipartite graphs. First, we colour each edge of the complete bipartite graph $K_{n,n}$ uniformly randomly from amongst ${r}$ colours and show that if ${r}$ grows…

Probability · Mathematics 2023-01-13 Ghurumuruhan Ganesan

Ordered matchings, defined as graphs with linearly ordered vertices, where each vertex is connected to exactly one edge, play a crucial role in the area of ordered graphs and their homomorphisms. Therefore, we consider related problems from…

Computational Complexity · Computer Science 2025-12-01 Michal Čertík , Andreas Emil Feldmann , Jaroslav Nešetřil , Paweł Rzążewski