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We investigate symmetric edge polytopes generated by Erd\H{o}s--R\'enyi random graphs in a high-dimensional regime. These objects provide a natural and largely unexplored model of random lattice polytopes, in which geometric properties are…

Combinatorics · Mathematics 2026-03-12 Torben Donzelmann , Martina Juhnke , Benedikt Rednoß , Christoph Thäle

A graph is said to be globally rigid if almost all embeddings of the graph's vertices in the Euclidean plane will define a system of edge-length equations with a unique (up to isometry) solution. In 2007, Jackson, Servatius and Servatius…

Combinatorics · Mathematics 2024-01-29 Sean Dewar

An important theme of recent research in Ramsey theory has been establishing pseudorandomness properties of Ramsey graphs. An $N$-vertex graph is called $C$-Ramsey if it has no homogeneous set of size $C\log N$. A theorem of Bukh and…

Combinatorics · Mathematics 2019-10-04 Matthew Jenssen , Peter Keevash , Eoin Long , Liana Yepremyan

Graphlets are subgraphs rooted at a fixed vertex. The number of occurrences of graphlets aligned to a particular vertex, called graphlet degree sequence (gds), gives a topological description of the surrounding of the analyzed vertex.…

Combinatorics · Mathematics 2026-01-01 David Hartman , Aneta Pokorná , Daniel Trlifaj , Lluís Vena

A cactus graph is a connected graph in which every block is either an edge or a cycle. In this paper, we will examine cactus graphs where all the blocks are $3$-cycles, i.e., triangular cactus graphs, of diameter $4$. Our main focus is to…

Commutative Algebra · Mathematics 2025-02-27 Rodica Dinu , Nayana Shibu Deepthi

We introduce a notion of Ricci curvature for Cayley graphs that can be thought of as "medium-scale" because it is neither infinitesimal nor asymptotic, but based on a chosen finite radius parameter. We argue that it gives the foundation for…

Group Theory · Mathematics 2020-07-06 Assaf Bar-Natan , Moon Duchin , Robert Kropholler

The 1-2-3 Conjecture asks whether almost all graphs can be (edge-)labelled with $1,2,3$ so that no two adjacent vertices are incident to the same sum of labels. In the last decades, several aspects of this problem have been studied in…

Combinatorics · Mathematics 2021-02-17 Julien Bensmail , Hervé Hocquard , Dimitri Lajou , Éric Sopena

For a given hypergraph, an orientation can be assigned to the vertex-edge incidences. This orientation is used to define the adjacency and Laplacian matrices. In addition to studying these matrices, several related structures are…

Combinatorics · Mathematics 2015-09-08 Nathan Reff

Design matrices are sparse matrices in which the supports of different columns intersect in a few positions. Such matrices come up naturally when studying problems involving point sets with many collinear triples. In this work we consider…

Combinatorics · Mathematics 2018-03-13 Zeev Dvir , Ankit Garg , Rafael Oliveira , József Solymosi

Centrality measures are used in network science to identify the most important vertices for transmission of information and dynamics on a graph. One of these measures, introduced by Estrada and collaborators, is the $\beta$-subgraph…

Combinatorics · Mathematics 2021-06-08 Francesco Ballini , Nikita Deniskin

Suppose a graph has no large balanced bicliques, but has large minimum degree. Then what can we say about its induced subgraphs? This question motivates the study of degree-boundedness, which is like $\chi$-boundedness but for minimum…

Combinatorics · Mathematics 2024-11-14 Xiying Du , Rose McCarty

Let $G$ be an undirected simple connected graph. We say a vertex $u$ is eccentric to a vertex $v$ in $G$ if $d(u,v)=\max\{d(v,w): w\in V(G)\}$. The eccentric graph, $E(G)$ of $G$ is a graph defined on the same vertex set as of $G$ and two…

Combinatorics · Mathematics 2023-09-13 Anita Arora , Rajiv Mishra

The purpose of this paper is to analyze the degree index and clustering index in random graphs. The degree index in our setup is a certain measure of degree irregularity whose basic properties are well studied in the literature, and the…

Probability · Mathematics 2026-03-11 Ümit Işlak , Barış Yeşiloğlu

We derive upper and lower bounds for the vertex-isoperimetric number of the incidence graphs of unitals and determine its order of magnitude. In the case when a unital contains sufficiently large arcs, these bounds agree and give rise to…

Combinatorics · Mathematics 2017-12-07 Alice M. W. Hui , Muhammad Adib Surani , Sanming Zhou

Various topological indices, based on the distances between the vertices of a graph, are widely used in theoretical chemistry. The degree resistance distance of a graph $G$ is defined as ${D_R}(G) = \sum\limits_{\{u,v\} \subseteq V(G)}…

Combinatorics · Mathematics 2016-04-19 Jia-Bao Liu , Xiang-Feng Pan

The atom-bond connectivity (ABC) index is a degree-based molecular structure descriptor that can be used for modelling thermodynamic properties of organic chemical compounds. Motivated by its applicable potential, a series of investigations…

Combinatorics · Mathematics 2016-10-11 Darko Dimitrov , Barbara Ikica , Riste Škrekovski

We study the existence of oriented paths with two blocks in oriented graphs under semidegree conditions. A block of an oriented path is a maximal directed subpath. Given positive integers $k$ and $\ell$ with $k/2\le \ell < k$, we establish…

Combinatorics · Mathematics 2025-04-01 Irena Penev , S Taruni , Stéphan Thomassé , Ana Trujillo-Negrete , Mykhaylo Tyomkyn

Embedding graph nodes into a vector space can allow the use of machine learning to e.g. predict node classes, but the study of node embedding algorithms is immature compared to the natural language processing field because of a diverse…

Machine Learning · Computer Science 2018-02-20 Kento Nozawa , Masanari Kimura , Atsunori Kanemura

Making use of a majorization technique for a suitable class of graphs, we derive upper and lower bounds for some topological indices depending on the degree sequence over all vertices, namely the first general Zagreb index and the first…

Combinatorics · Mathematics 2015-03-27 Monica Bianchi , Alessandra Cornaro , José Luis Palacios , Anna Torriero

We consider the number of crossings in a random embedding of a graph, $G$, with vertices in convex position. We give explicit formulas for the mean and variance of the number of crossings as a function of various subgraph counts of $G$.…

Probability · Mathematics 2024-10-14 Santiago Arenas-Velilla , Octavio Arizmendi , J. E. Paguyo
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