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Related papers: Divisible design graphs with selfloops

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A $k$-regular graph is called a divisible design graph if its vertex set can be partitioned into $m$ classes of size $n$, such that two distinct vertices from the same class have exactly $\lambda_1$ common neighbours, and two vertices from…

Combinatorics · Mathematics 2022-10-20 Dmitry Panasenko

The eccentricity matrix $\epsilon(G)$, of a connected graph $G$ is obtained by retaining the maximum distance from each row and column of the distance matrix of $G$ and the other entries are assigned with 0. In this paper, we discuss the…

Combinatorics · Mathematics 2024-05-01 Anjitha Ashokan , Chithra A

We investigate in some detail a recently suggested general class of ensembles of sparse undirected random graphs based on a hidden stub-coloring, with or without the restriction to nondegenerate graphs. The calculability of local and global…

Statistical Mechanics · Physics 2009-11-10 Bo Soderberg

We present recent advances in harmonic analysis on infinite graphs. Our approach combines combinatorial tools with new results from the theory of unbounded Hermitian operators in Hilbert space, geometry, boundary constructions, and spectral…

Combinatorics · Mathematics 2020-10-26 Sergey Bezuglyi , Palle E. T. Jorgensen

We apply model theoretic methods to the problem of existence of countable universal graphs with finitely many forbidden connected subgraphs. We show that to a large extent the question reduces to one of local finiteness of an…

Logic · Mathematics 2016-09-07 Gregory Cherlin , Saharon Shelah , Niandong Shi

Differential calculus on discrete sets is developed in the spirit of noncommutative geometry. Any differential algebra on a discrete set can be regarded as a `reduction' of the `universal differential algebra' and this allows a systematic…

High Energy Physics - Theory · Physics 2009-10-28 A. Dimakis , F. Müller-Hoissen

We examine the capacity of the complementarity spectrum to distinguish non-isomorphic digraphs. We focus on the seven families with exactly three complementarity eigenvalues. Our findings reveal that in some, but not all families, any two…

Combinatorics · Mathematics 2024-03-19 Diego Bravo , Florencia Cubría , Marcelo Fiori , Gustavo Rama

Let A be a graph type and B an equivalence relation on a group $G$. Let $[g]$ be the equivalence class of $g$ with respect to the equivalence relation B. The B superA graph of $G$ is an undirected graph whose vertex set is $G$ and two…

Combinatorics · Mathematics 2025-09-24 G. Arunkumar , Peter J. Cameron , R. Ganeshbabu , Rajat Kanti Nath

The theory of graphons has proven to be a powerful tool in many areas of graph theory. In this paper, we introduce several foundational aspects of the theory of digraphons -- asymmetric two-variable functions that arise as limits of…

Combinatorics · Mathematics 2025-12-16 Jan Hladký , Petr Savický

Nonstandard graphs have been defined and examined in prior works. The present work does the same for nonstandard digraphs. Since digraphs have more structure than do graphs, the present discussion requires more complicated definitions and…

Combinatorics · Mathematics 2009-04-28 A. H. Zemanian

We give bounds on the L(2,1)-labeling number of a simple graph in terms of its order and its maximum degree. We also describe an infinite class of graphs of which the elements have the highest L(2,1)-labeling numbers in terms of their…

Combinatorics · Mathematics 2013-11-08 Cole Franks

`Double edge swaps' transform one graph into another while preserving the graph's degree sequence, and have thus been used in a number of popular Markov chain Monte Carlo (MCMC) sampling techniques. However, while double edge-swaps can…

Combinatorics · Mathematics 2020-12-29 Joel Nishimura

Motivated by his work on the classification of countable homogeneous oriented graphs, Cherlin asked about the typical structure of oriented graphs (i) without a transitive triangle, or (ii) without an oriented triangle. We give an answer to…

Combinatorics · Mathematics 2015-12-15 Deryk Osthus , Daniela Kühn , Timothy Townsend , Yi Zhao

Given an infinite graph $G$ on countably many vertices, and a closed, infinite set $\Lambda$ of real numbers, we prove the existence of an unbounded self-adjoint operator whose graph is $G$ and whose spectrum is $\Lambda$.

Spectral Theory · Mathematics 2017-08-08 Ehssan Khanmohammadi

Associative spectra of graph algebras are examined with the help of homomorphisms of DFS trees. Undirected graphs are classified according to the associative spectra of their graph algebras; there are only three distinct possibilities:…

Combinatorics · Mathematics 2021-05-20 Erkko Lehtonen , Tamás Waldhauser

A graph of order $n>3$ is called {switching separable} if its modulo-2 sum with some complete bipartite graph on the same set of vertices is divided into two mutually independent subgraphs, each having at least two vertices. We prove the…

Combinatorics · Mathematics 2013-03-11 Denis Krotov

In this monography, it is proposed to consider the concepts of spectra of edge cuts and edge cycles of a graph as a basic mathematical structure for solving the problem of graph isomorphism. An edge cut is defined by an edge and the…

Combinatorics · Mathematics 2024-06-13 Sergey Kurapov , Maxim Davidovsky

The paper systematically classifies rings based on the dominant metric dimensions (Ddim) of their associated CZDG, establishing consequential bounds for the Ddim of these compressed zero-divisor graphs. The authors investigate the interplay…

Commutative Algebra · Mathematics 2024-05-09 Nasir Ali , Hafiz Muhammad Afzal Siddiqui , Muhammad Imran Qureshi

We define a range of new coarse geometric invariants based on various graph-theoretic measures of complexity for finite graphs, including: treewidth, pathwidth, cutwidth and bandwidth. We prove that, for bounded degree graphs, these…

Metric Geometry · Mathematics 2025-08-07 Wanying Huang , David Hume , Samuel J. Kelly , Ryan Lam

Probabilistic dependency graphs (PDGs) are a flexible class of probabilistic graphical models, subsuming Bayesian Networks and Factor Graphs. They can also capture inconsistent beliefs, and provide a way of measuring the degree of this…

Data Structures and Algorithms · Computer Science 2023-11-10 Oliver E. Richardson , Joseph Y. Halpern , Christopher De Sa