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Related papers: Godsil-McKay switchings for gain graphs

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It is known that complete multipartite graphs are determined by their distance spectrum but not by their adjacency spectrum. The Seidel spectrum of a graph $G$ on more than one vertex does not determine the graph, since any graph obtained…

Combinatorics · Mathematics 2019-02-08 Abraham Berman , Shaked-Monderer , Ranveer Singh , Xiao-Dong Zhang

Graph Transformer (GT) has recently emerged as a promising neural network architecture for learning graph-structured data. However, its global attention mechanism with quadratic complexity concerning the graph scale prevents wider…

Machine Learning · Computer Science 2024-12-09 Ningyi Liao , Zihao Yu , Siqiang Luo

We provide an abundance of strongly regular graphs (SRGs) for certain parameters $(n, k, \lambda, \mu)$ with $n < 100$. For this we use Godsil-McKay (GM) switching with a partition of type $4,n-4$ and Wang-Qiu-Hu (WQH) switching with a…

Combinatorics · Mathematics 2022-07-07 Ferdinand Ihringer

In graph learning, maps between graphs and their subgraphs frequently arise. For instance, when coarsening or rewiring operations are present along the pipeline, one needs to keep track of the corresponding nodes between the original and…

Machine Learning · Computer Science 2023-02-01 Marco Pegoraro , Riccardo Marin , Arianna Rampini , Simone Melzi , Luca Cosmo , Emanuele Rodolà

A complex unit gain graph is a graph where each orientation of an edge is given a complex unit, which is the inverse of the complex unit assigned to the opposite orientation. We extend some fundamental concepts from spectral graph theory to…

Combinatorics · Mathematics 2014-08-26 Nathan Reff

In this paper we present a general procedure that allows for the reduction or expansion of any network (considered as a weighted graph). This procedure maintains the spectrum of the network's adjacency matrix up to a set of eigenvalues…

Dynamical Systems · Mathematics 2011-11-15 L. A. Bunimovich , B. Z. Webb

In order to obtain perfect state transfer between two sites in a network of interacting qubits, their corresponding vertices in the underlying graph must satisfy a combinatorial property called strong cospectrality. Here we determine the…

Combinatorics · Mathematics 2018-05-23 Gabriel Coutinho

Several researchers have recently explored various graph parameters that can or cannot be characterized by the spectrum of a matrix associated with a graph. In this paper we show that several NP-hard zero forcing numbers are not…

Combinatorics · Mathematics 2022-04-25 Aida Abiad , Boris Brimkov , Jane Breen , Thomas R. Cameron , Himanshu Gupta , Ralihe R. Villagrán

We study geometric presentations of braid groups for particles that are constrained to move on a graph, i.e. a network consisting of nodes and edges. Our proposed set of generators consists of exchanges of pairs of particles on junctions of…

Mathematical Physics · Physics 2021-05-12 Byung Hee An , Tomasz Maciazek

In this brief communication, we investigate the cospectral as well integral chain graphs for Seidel matrix, a key component to study the structural properties of equiangular lines in space. We derive a formula that allows to generate an…

Combinatorics · Mathematics 2023-08-02 Santanu Mandal

We show that the strongly regular graph on non-isotropic points of one type of the polar spaces of type $U(n, 2)$, $O(n, 3)$, $O(n, 5)$, $O^+(n, 3)$, and $O^-(n, 3)$ are not determined by its parameters for $n \geq 6$. We prove this by…

Combinatorics · Mathematics 2019-07-16 Ferdinand Ihringer , Akihiro Munemasa

Learning representation on graph plays a crucial role in numerous tasks of pattern recognition. Different from grid-shaped images/videos, on which local convolution kernels can be lattices, however, graphs are fully coordinate-free on…

Machine Learning · Computer Science 2018-11-13 Jiatao Jiang , Zhen Cui , Chunyan Xu , Jian Yang

A suitable extra differential on graph complexes can lead to a pairing of its cohomological classes. Many such extra differentials are known for various graph complexes, including Kontsevich's graph complex $GC_n$ for odd $n$. In this paper…

Quantum Algebra · Mathematics 2020-05-14 Marko Živković

Two signed graphs are called switching isomorphic if one of them is isomorphic to a switching equivalent of the other. To determine the number of switching non-isomorphic signed graphs on a specific graph, we will establish a method based…

Combinatorics · Mathematics 2019-09-17 Yousef Bagheri , Alireza Moghadamfar , Farzaneh Ramezani

Current methods of graph signal processing rely heavily on the specific structure of the underlying network: the shift operator and the graph Fourier transform are both derived directly from a specific graph. In many cases, the network is…

Signal Processing · Electrical Eng. & Systems 2023-03-31 Kathryn Beck , Mahya Ghandehari , Jeannette Janssen , Nauzer Kalyaniwalla

The distance matrix of a connected graph is the symmetric matrix with columns and rows indexed by the vertices and entries that are the pairwise distances between the corresponding vertices. We give a construction for graphs which differ in…

Combinatorics · Mathematics 2016-06-23 Kristin Heysse

A unitary shift operator (GSO) for signals on a graph is introduced, which exhibits the desired property of energy preservation over both backward and forward graph shifts. For rigour, the graph differential operator is also derived in an…

Signal Processing · Electrical Eng. & Systems 2019-09-18 Bruno Scalzo Dees , Ljubisa Stankovic , Milos Dakovic , Anthony G. Constantinides , Danilo P. Mandic

A conjugate skew gain graph is a skew gain graph with the labels (also called, the conjugate skew gains) from the field of complex numbes on the oriented edges such that they get conjugated when we reverse the orientation. In this paper we…

Combinatorics · Mathematics 2023-07-13 Shahul Hameed K , Ramakrishnan K O , Biju K

Large-scale graphs are widely used to represent object relationships in many real world applications. The occurrence of large-scale graphs presents significant computational challenges to process, analyze, and extract information. Graph…

Social and Information Networks · Computer Science 2019-10-11 Yu Jin , Andreas Loukas , Joseph F. JaJa

In this article we are introducing combinatorial spectra of graphs, this is a generalization of $H$-Hamiltonian spectra. The main motivation was to made from $H$-Hamiltonian spectra an operation and develop some algebra in this field. An…

Combinatorics · Mathematics 2023-11-21 Martin Dzúrik