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A hypergraph is a $T_0$-hypergraph if for every two different vertices of the hypergraph there exists an edge containing one of the vertices and not containing the other. A general method for the enumeration of certain classes of…

Combinatorics · Mathematics 2014-11-18 Goran Kilibarda , Vladeta Jovović

We continue the study of $(\mathrm{tw},\omega)$-bounded graph classes, that is, hereditary graph classes in which the treewidth can only be large due to the presence of a large clique, with the goal of understanding the extent to which this…

Combinatorics · Mathematics 2023-12-19 Clément Dallard , Martin Milanič , Kenny Štorgel

In this work, we delve into the study of the 2-switch-degree of a graph $G$, which is nothing more than the degree of $G$ as a vertex of the realization graph $\mathcal{G}(d)$ associated with the degree sequence $d$ of $G$. We explore the…

Combinatorics · Mathematics 2026-03-10 Victor N. Schvöllner , Adrián Pastine

For a given graph $\mathcal{G}$ of order $n$ with $m$ edges, and a real symmetric matrix associated to the graph, $M\left(\mathcal{G}\right)\in\mathbb{R}^{n\times n}$, the interlacing graph reduction problem is to find a graph…

Spectral Theory · Mathematics 2020-08-11 Noam Leiter , Daniel Zelazo

Diestel and M\"uller showed that the connected tree-width of a graph $G$, i.e., the minimum width of any tree-decomposition with connected parts, can be bounded in terms of the tree-width of $G$ and the largest length of a geodesic cycle in…

Combinatorics · Mathematics 2017-02-15 Matthias Hamann , Daniel Weißauer

Let G be a simple graph without isolated vertices. For a vertex i in G, the degree d_i is the number of vertices adjacent to i and the average 2-degree m_i is the mean of the degrees of the vertices which are adjacent to i. The sequence of…

Combinatorics · Mathematics 2018-11-08 Yu-pei Huang , Chia-an Liu , Chih-wen Weng

A subset $X$ of vertices in a graph $G$ is a {\em diameter 2 subset} if the distance of any two vertices of $X$ is at most two {\em in $G[X]$}. Relaxing this notion, a subset $X$ of vertices in a graph $G$ is a {\em 2-reachable subset} if…

Combinatorics · Mathematics 2025-06-16 Andras Gyarfas , Gabor N. Sarkozy

Metric dimension is a graph parameter that has been applied to robot navigation and finding low-dimensional vector embeddings. Throttling entails minimizing the sum of two available resources when solving certain graph problems. In this…

Combinatorics · Mathematics 2025-10-02 Boris Brimkov , Peter Diao , Jesse Geneson , Carolyn Reinhart , Shen-Fu Tsai , William Wang , Kyle Worley

Hyperedge-Replacement grammars (HR) have been introduced by Courcelle in order to extend the notion of context-free sets from words and trees to graphs of bounded tree-width. While for words and trees the syntactic restrictions that…

Formal Languages and Automata Theory · Computer Science 2024-02-29 Mark Chimes , Radu Iosif , Florian Zuleger

We analyze the threshold network model in which a pair of vertices with random weights are connected by an edge when the summation of the weights exceeds a threshold. We prove some convergence theorems and central limit theorems on the…

Probability · Mathematics 2007-05-23 Norio Konno , Naoki Masuda , Rahul Roy , Anish Sarkar

We present a conceptually clear and algorithmically useful framework for parameterizing the costs of tensor network contraction. Our framework is completely general, applying to tensor networks with arbitrary bond dimensions, open legs, and…

Data Structures and Algorithms · Computer Science 2019-06-04 Bryan O'Gorman

The metric dimension (MD) of a graph is a combinatorial notion capturing the minimum number of landmark nodes needed to distinguish every pair of nodes in the graph based on graph distance. We study how much the MD can increase if we add a…

Combinatorics · Mathematics 2021-11-16 Satvik Mashkaria , Gergely Ódor , Patrick Thiran

A graph $G$ realizes the degree sequence $S$ if the degrees of its vertices is $S$. Hakimi gave a necessary and sufficient condition to guarantee that there exists a connected multigraph realizing $S$. Taylor later proved that any connected…

Discrete Mathematics · Computer Science 2018-09-17 Nicolas Bousquet , Arnaud Mary

We investigate the tractability of a simple fusion of two fundamental structures on graphs, a spanning tree and a perfect matching. Specifically, we consider the following problem: given an edge-weighted graph, find a minimum-weight…

Data Structures and Algorithms · Computer Science 2024-07-12 Kristóf Bérczi , Tamás Király , Yusuke Kobayashi , Yutaro Yamaguchi , Yu Yokoi

Many recent works address the question of characterizing induced obstructions to bounded treewidth. In 2022, Lozin and Razgon completely answered this question for graph classes defined by finitely many forbidden induced subgraphs. Their…

This is a companion paper to the paper "Hyperstability in the Erdos-Sos Conjecture". In that paper the following rough structure theorem was proved for graphs G containing no copy of a bounded degree tree T: from any such G, one can delete…

Combinatorics · Mathematics 2024-09-24 Alexey Pokrovskiy

In this paper we introduce a new notion of convergence of sparse graphs which we call Large Deviations or LD-convergence and which is based on the theory of large deviations. The notion is introduced by "decorating" the nodes of the graph…

Probability · Mathematics 2013-02-20 Christian Borgs , Jennifer Chayes , David Gamarnik

A constant-rate encoder--decoder pair is presented for a fairly large family of two-dimensional (2-D) constraints. Encoding and decoding is done in a row-by-row manner, and is sliding-block decodable. Essentially, the 2-D constraint is…

Information Theory · Computer Science 2008-08-06 Ido Tal , Tuvi Etzion , Ron M. Roth

The score of a vertex $x$ in an oriented graph is defined to be its outdegree, \emph{i.e.}, the number of arcs with initial vertex $x$. The score sequence of an oriented graph is the sequence of all scores arranged in nondecreasing order.…

Combinatorics · Mathematics 2024-12-17 Severino V. Gervacio

In this report we present an algorithm solving Triangle Counting in time $O(d^2n+m)$, where n and m, respectively, denote the number of vertices and edges of a graph G and d denotes its twin-width, a recently introduced graph parameter. We…

Data Structures and Algorithms · Computer Science 2022-02-15 Stefan Kratsch , Florian Nelles , Alexandre Simon