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The Picard group of an undirected graph is a finitely generated abelian group, and the Jacobian is the torsion subgroup of the Picard group. These groups can be computed by using the Smith normal form of the Laplacian matrix of the graph or…

Combinatorics · Mathematics 2023-02-22 Jaiung Jun , Youngsu Kim , Matthew Pisano

Two graphs are cospectral if their respective adjacency matrices have the same multiset of eigenvalues, and generalized cospectral if they are cospectral and so are their complements. We study generalized cospectrality in relation to…

Logic in Computer Science · Computer Science 2022-10-12 Aida Abiad , Anuj Dawar , Octavio Zapata

A set of graphs are called cospectral if their adjacency matrices have the same characteristic polynomial. In this paper we introduce a simple method for constructing infinite families of cospectral regular graphs. The construction is valid…

Combinatorics · Mathematics 2021-10-12 Michael Haythorpe , Alex Newcombe

We give a constructive account of the de Groot duality of stably compact spaces in the setting of strong proximity lattice, a point-free representation of a stably compact space. To this end, we introduce a notion of strong continuous…

Logic in Computer Science · Computer Science 2020-03-10 Tatsuji Kawai

Random graphs have proven to be one of the most important and fruitful concepts in modern Combinatorics and Theoretical Computer Science. Besides being a fascinating study subject for their own sake, they serve as essential instruments in…

Combinatorics · Mathematics 2007-05-23 Michael Krivelevich , Benny Sudakov

We study the distribution of the cokernels of adjacency matrices (the Smith groups) of certain models of random $r$-regular graphs and directed graphs, using recent mixing results of M\'esz\'aros. We explain how convergence of such…

Probability · Mathematics 2018-07-02 Hoi H. Nguyen , Melanie Matchett Wood

In this work, we develop a spectral theory for hypergraph limits. We prove the convergence of the spectra of adjacency and Laplacian matrices for hypergraph sequences converging in the $1$-cut metric. On the other hand, we give examples of…

Combinatorics · Mathematics 2025-11-06 Ágnes Backhausz , Christian Kuehn , Sjoerd van der Niet , Giulio Zucal

A signed graph is a graph whose edges are labeled either positive or negative. Corresponding to the two signed distance matrices defined for signed graphs, we define two signed distance laplacian matrices. We characterize balance in signed…

Combinatorics · Mathematics 2020-10-12 Roshni T Roy , K A Germina , K Shahul Hameed , Thomas Zaslavsky

In this paper, a new measurement to compare two large-scale graphs based on the theory of quantum probability is proposed. An explicit form for the spectral distribution of the corresponding adjacency matrix of a graph is established. Our…

Discrete Mathematics · Computer Science 2018-07-03 Hayoung Choi , Hosoo Lee , Yifei Shen , Yuanming Shi

Graph representation matrices are essential tools in graph data analysis. Recently, Hermitian adjacency matrices have been proposed to investigate directed graph structures. Previous studies have demonstrated that these matrices can extract…

Combinatorics · Mathematics 2025-07-21 Keishi Sando , Hideitsu Hino

A connected graph can be associated with two distinct evolution algebras. In the first case, the structural matrix is the adjacency matrix of the graph itself. In the second case, the structural matrix is the transition probabilities matrix…

Combinatorics · Mathematics 2024-05-22 Paula Cadavid , Mary Luz Rodiño Montoya , Pablo M. Rodriguez , Sebastian J. Vidal

The paper gives a thorough introduction to spectra of digraphs via its Hermitian adjacency matrix. This matrix is indexed by the vertices of the digraph, and the entry corresponding to an arc from $x$ to $y$ is equal to the complex unity…

Combinatorics · Mathematics 2015-05-07 Krystal Guo , Bojan Mohar

The concept of the integrated adjacency matrix for mixed graphs was first introduced in [9], where its spectral properties were analyzed in relation to the structural characteristics of the mixed graph. Building upon this foundation, this…

Combinatorics · Mathematics 2025-07-08 G. Kalaivani , R. Rajkumar

A drawing of a graph in the plane is {\it pseudolinear} if the edges of the drawing can be extended to doubly-infinite curves that form an arrangement of pseudolines, that is, any pair of edges crosses precisely once. A special case are…

For families of 4-regular directed circulant graphs with $n$ vertices, we count the number of primitive periodic orbits of length up to at least $n$. The relevant counting techniques are then extended to count the number of primitive pseudo…

Combinatorics · Mathematics 2021-09-29 Lauren Engelthaler , Isaac Hellerman , Tori Hudgins

We analyze a random projection method for adjacency matrices, studying its utility in representing sparse graphs. We show that these random projections retain the functionality of their underlying adjacency matrices while having extra…

Data Structures and Algorithms · Computer Science 2023-09-06 Frank Qiu

We give a complete characterization of simple graphs whose adjacency matrices generate binary linear complementary dual (LCD) codes. In particular, we completely characterize a distance-regular graph which yields an LCD code in terms of the…

Combinatorics · Mathematics 2026-05-18 Keita Ishizuka

We develop some aspects of a general theory of presentations of subshifts by labelled directed graphs, in particular by compact graphs. Also considered are synchronization properties of subshifts that lead to presentations by countable…

Dynamical Systems · Mathematics 2012-09-11 Wolfgang Krieger

In this paper, by presenting bi-periodic Lucas numbers as a binomial sum, we introduce the bi-periodic incomplete Lucas numbers. After that, by using the bi-periodic incomplete Lucas numbers, we derive the recurrence relation and the…

Number Theory · Mathematics 2016-01-19 Nazmiye Yilmaz , Yasin Yazlik , Necati Taskara

In an attempt to characterize the structure of eigenvectors of random regular graphs, we investigate the correlations between the components of the eigenvectors associated to different vertices. In addition, we provide numerical…

Mathematical Physics · Physics 2009-11-13 Yehonatan Elon