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A complex unit gain graph is a simple graph in which each orientation of an edge is given a complex number with modulus 1 and its inverse is assigned to the opposite orientation of the edge. In this article, first we establish bounds for…

Combinatorics · Mathematics 2019-10-04 Ranjit Mehatari , M. Rajesh Kannan , Aniruddha Samanta

While tokenized graph Transformers have demonstrated strong performance in node classification tasks, their reliance on a limited subset of nodes with high similarity scores for constructing token sequences overlooks valuable information…

Machine Learning · Computer Science 2025-02-18 Jinsong Chen , Hanpeng Liu , John E. Hopcroft , Kun He

The spectrum of the normalized Laplacian matrix cannot determine the number of edges in a graph, however finding constructions of cospectral graphs with differing number of edges has been elusive. In this paper we use basic properties of…

Combinatorics · Mathematics 2014-10-27 Steve Butler

Graph complements G(n) of cyclic graphs are circulant, vertex-transitive, claw-free, strongly regular, Hamiltonian graphs with a Z(n) symmetry, Shannon capacity 2 and known Wiener and Harary index. There is an explicit spectral zeta…

Combinatorics · Mathematics 2021-01-19 Oliver Knill

For a connected graph $G$, we present the concept of a new graph matrix related to its distance and Seidel matrix, called distance Seidel matrix $\mathcal{D}^S(G)$. Suppose that the eigenvalues of $\mathcal{D}^S(G)$ be $\partial_{1}^{S}(G)…

Combinatorics · Mathematics 2025-05-06 Haritha T , Chithra A.

Graph-based models require aggregating information in the graph from neighbourhoods of different sizes. In particular, when the data exhibit varying levels of smoothness on the graph, a multi-scale approach is required to capture the…

Machine Learning · Computer Science 2022-02-22 Felix L. Opolka , Yin-Cong Zhi , Pietro Liò , Xiaowen Dong

A $\mathbb{T}$-gain graph is a triple $\Phi=(G,\mathbb{T},\varphi)$ consisting of a graph $G=(V,E)$, the circle group $\mathbb{T}=\{z\in C: |z|=1\}$ and a gain function $\varphi:\overrightarrow{E}\rightarrow \mathbb{T}$ such that…

Combinatorics · Mathematics 2015-11-25 Yong Lu , Ligong Wang , Peng Xiao

In a graph, the switching operation reverses adjacencies between a subset of vertices and the others. For a hereditary graph class $\mathcal{G}$, we are concerned with the maximum subclass and the minimum superclass of $\mathcal{G}$ that…

Data Structures and Algorithms · Computer Science 2024-08-15 Dhanyamol Antony , Yixin Cao , Sagartanu Pal , R. B. Sandeep

We contribute to approximate algorithms for the quadratic assignment problem also known as graph matching. Inspired by the success of the fusion moves technique developed for multilabel discrete Markov random fields, we investigate its…

Computer Vision and Pattern Recognition · Computer Science 2021-08-23 Lisa Hutschenreiter , Stefan Haller , Lorenz Feineis , Carsten Rother , Dagmar Kainmüller , Bogdan Savchynskyy

This is the second part of the paper that provides a new strategy for the heterogeneous change detection (HCD) problem, that is, solving HCD from the perspective of graph signal processing (GSP). We construct a graph to represent the…

Computer Vision and Pattern Recognition · Computer Science 2022-08-09 Yuli Sun , Lin Lei , Dongdong Guan , Gangyao Kuang , Li Liu

Graphs are general and powerful data representations which can model complex real-world phenomena, ranging from chemical compounds to social networks; however, effective feature extraction from graphs is not a trivial task, and much work…

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

Graph Structure Learning (GSL) recently has attracted considerable attentions in its capacity of optimizing graph structure as well as learning suitable parameters of Graph Neural Networks (GNNs) simultaneously. Current GSL methods mainly…

Machine Learning · Computer Science 2022-01-17 Nian Liu , Xiao Wang , Lingfei Wu , Yu Chen , Xiaojie Guo , Chuan Shi

Identifying structures in common forms the basis for networked systems design and optimization. However, real structures represented by graphs are often of varying sizes, leading to the low accuracy of traditional graph classification…

Machine Learning · Computer Science 2024-09-04 Xiaoyu Zhang , Wenchuan Yang , Jiawei Feng , Bitao Dai , Tianci Bu , Xin Lu

Graph convolutional networks (GCNs) and its variants are designed for unsigned graphs containing only positive links. Many existing GCNs have been derived from the spectral domain analysis of signals lying over (unsigned) graphs and in each…

Machine Learning · Computer Science 2022-08-16 Rahul Singh , Yongxin Chen

Characterizing graphs by their spectra is an important topic in spectral graph theory, which has attracted a lot of attention of researchers in recent years. It is generally very hard and challenging to show a given graph to be determined…

Combinatorics · Mathematics 2020-11-02 Wei Wang , Fenjin Liu , Wei Wang

Let $n$ be any positive integer and let $F_n$ be the friendship (or Dutch windmill) graph with $2n+1$ vertices and $3n$ edges. Here we study graphs with the same adjacency spectrum as the $F_n$. Two graphs are called cospectral if the…

Combinatorics · Mathematics 2013-07-23 Alireza Abdollahi , Shahrooz Janbaz , Mohammad Reza Oboudi

We consider symmetric powers of a graph. In particular, we show that the spectra of the symmetric square of strongly regular graphs with the same parameters are equal. We also provide some bounds on the spectra of the symmetric squares of…

Combinatorics · Mathematics 2007-05-23 Koenraad Audenaert , Chris Godsil , Gordon Royle , Terry Rudolph

In representation learning on the graph-structured data, under heterophily (or low homophily), many popular GNNs may fail to capture long-range dependencies, which leads to their performance degradation. To solve the above-mentioned issue,…

Machine Learning · Computer Science 2021-06-29 Mengying Jiang , Guizhong Liu , Yuanchao Su , Xinliang Wu

Using a graph approach to quantum systems, we prove that descriptions of 3-dim Kochen-Specker (KS) setups as well as descriptions of 3-dim spin systems by means of Greechie lattices that we find in the literature are wrong. Correct lattices…

Quantum Physics · Physics 2010-10-13 Mladen Pavicic , Brendan D. McKay , Norman D. Megill , Kresimir Fresl
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