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The neighborhood degree list (NDL) is a graph invariant that refines information given by the degree sequence and joint degree matrix of a graph and is useful in distinguishing graphs having the same degree sequence. We show that the space…

Combinatorics · Mathematics 2019-09-17 Michael D. Barrus , Elizabeth Donovan

The characterization of distance-regular Cayley graphs originated from the problem of identifying strongly regular Cayley graphs, or equivalently, regular partial difference sets. In this paper, a classification of distance-regular Cayley…

Combinatorics · Mathematics 2022-03-25 Xueyi Huang , Kinkar Chandra Das , Lu Lu

For a simple graph $\Gamma$, a (bipartite)tree-line graph and a tree-graph of $\Gamma$ can be defined. With a (bipartite)tree-line graph constructed by the function $(b)\ell$, we study the continuous quantum walk on $(b)\ell ^n \Gamma$. An…

Combinatorics · Mathematics 2026-05-05 Kang Musung

We offer a solution to a long-standing problem in the physics of networks, the creation of a plausible, solvable model of a network that displays clustering or transitivity -- the propensity for two neighbors of a network node also to be…

Statistical Mechanics · Physics 2009-08-13 M. E. J. Newman

A few properties of unitary Cayley graphs are explored using their eigenvalues. It is shown that the adjacency algebra of a unitary Cayley graph is a coherent algebra. Finally, a class of unitary Cayley graphs that are distance regular are…

Number Theory · Mathematics 2017-07-11 A. Satyanarayana Reddy

Mutual visibility in graphs provides a framework for analysing how vertices can observe one another along shortest paths free of internal obstructions. The visibility polynomial, which enumerates mutual-visibility sets of all orders, has…

Combinatorics · Mathematics 2026-04-10 Tonny K B , Shikhi M

A circle graph is an intersection graph of a set of chords of a circle. We describe the unavoidable induced subgraphs of circle graphs with large treewidth. This includes examples that are far from the `usual suspects'. Our results imply…

Combinatorics · Mathematics 2022-12-23 Robert Hickingbotham , Freddie Illingworth , Bojan Mohar , David R. Wood

We discuss a general parametrization for vertices of quantum graphs and show, in particular, how the $\delta'_s$ and $\delta'$ coupling at an $n$ edge vertex can be approximated by means of $n+1$ couplings of the $\delta$ type provided the…

Quantum Physics · Physics 2009-11-10 Taksu Cheon , Pavel Exner

If we are given a connected finite graph $G$ and a subset of its vertices $V_{0}$, we define a distance-residual graph as a graph induced on the set of vertices that have the maximal distance from $V_{0}$. Some properties and examples of…

Combinatorics · Mathematics 2007-05-23 Primoz Luksic , Tomaz Pisanski

We give a complete characterization of bipartite graphs having tree-like Galois lattices. We prove that the poset obtained by deleting bottom and top elements from the Galois lattice of a bipartite graph is tree-like if and only if the…

Discrete Mathematics · Computer Science 2014-06-03 Nicola Apollonio , Massimiliano Caramia , Paolo Giulio Franciosa

Observational data usually comes with a multimodal nature, which means that it can be naturally represented by a multi-layer graph whose layers share the same set of vertices (users) with different edges (pairwise relationships). In this…

Machine Learning · Computer Science 2015-08-31 Xiaowen Dong , Pascal Frossard , Pierre Vandergheynst , Nikolai Nefedov

In this paper, we define a class of auxiliary graphs associated with simple undirected graphs. This class of auxiliary graphs is based on the set of spanning trees of the original graph and the edges constituting those spanning trees. A…

Combinatorics · Mathematics 2019-02-26 Abhishek Garg , Mahipal Jadeja , Rahul Muthu

We study the class of 1-perfectly orientable graphs, that is, graphs having an orientation in which every out-neighborhood induces a tournament. 1-perfectly orientable graphs form a common generalization of chordal graphs and circular arc…

Combinatorics · Mathematics 2016-03-08 Tatiana Romina Hartinger , Martin Milanič

This paper studies the structure of graphs with given tree-width and excluding a fixed complete bipartite subgraph, which generalises the bounded degree setting. We give a new structural description of such graphs in terms of so-called…

Combinatorics · Mathematics 2025-12-15 Chun-Hung Liu , David R. Wood

Mixed graphs can be seen as digraphs with arcs and edges (or digons, that is, two opposite arcs). In this paper, we consider the case where such graphs are bipartite and in which the undirected and directed degrees are one. The best graphs,…

Combinatorics · Mathematics 2024-03-29 C. Dalfó , G. Erskine , G. Exoo , M. A. Fiol , J. Tuite

We compute numerically the homology of several graph complexes in low loop orders, extending previous results.

Quantum Algebra · Mathematics 2023-12-21 Simon Brun , Thomas Willwacher

Hyperbolicity is a property of a graph that may be viewed as being a "soft" version of a tree, and recent empirical and theoretical work has suggested that many graphs arising in Internet and related data applications have hyperbolic…

Social and Information Networks · Computer Science 2013-09-17 Wei Chen , Wenjie Fang , Guangda Hu , Michael W. Mahoney

A graph is an efficient open (resp.\ closed) domination graph if there exists a subset of vertices whose open (resp.\ closed) neighborhoods partition its vertex set. Graphs that are efficient open as well as efficient closed (shortly EOCD…

Combinatorics · Mathematics 2015-11-09 Sandi Klavzar , Iztok Peterin , Ismael G. Yero

A random intersection graph is constructed by assigning independently to each vertex a subset of a given set and drawing an edge between two vertices if and only if their respective subsets intersect. In this paper a model is developed in…

Probability · Mathematics 2015-09-24 Maria Deijfen , Willemien Kets

This work provides a structural characterisation of hereditary graph classes that do not contain a star forest, several graphs obtained from star forests by subset complementation, a union of cliques, and the complement of a union of…

Combinatorics · Mathematics 2017-11-09 Aistis Atminas