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Related papers: Ramanujan Graphs and Interlacing Families

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A map is a panorama in small scale. In this half-survey, half-research paper we give general results on Ramanujan expansions. We don't include the ocean of results from the literature on the two classes (see Schwarz-Spilker Book, also…

Number Theory · Mathematics 2018-12-11 Giovanni Coppola

In a breakthrough work, Marcus-Spielman-Srivastava recently showed that every $d$-regular bipartite Ramanujan graph has a 2-lift that is also $d$-regular bipartite Ramanujan. As a consequence, a straightforward iterative brute-force search…

Combinatorics · Mathematics 2015-09-01 Karthekeyan Chandrasekaran , Ameya Velingker

We show some definite integrals connecting to infinite series, studied in Ramanujan's paper, titled "On question 330 of Professor Sanjana". We present few recursive methods to evaluate these definite integrals in various cases and we…

General Mathematics · Mathematics 2011-12-21 Ramesh Kumar Muthumalai

The authors of this paper have used the theory of Riordan matrices to introduce the notion of a Riordan graph in \cite{CJKM}. Riordan graphs are proved to have a number of interesting (fractal) properties, and they are a far-reaching…

Combinatorics · Mathematics 2018-01-23 Gi-Sang Cheon , Ji-Hwan Jung , Sergey Kitaev , Seyed Ahmad Mojallal

We completely characterize triangulations of the projective plane that have a spanning bipartite quadrangulation subgraph. This is an affirmative answer to a question by K\"undgen and Ramamurthi (J Combin Theory Ser B 85, 307--337, 2002)…

Combinatorics · Mathematics 2026-04-24 Kenta Noguchi

The study of Ramanujan-type congruences for functions specific to additive number theory has a long and rich history. Motivated by recent connections between divisor sums and overpartitions via congruences in arithmetic progressions, we…

Number Theory · Mathematics 2022-05-12 William Craig , Mircea Merca

Graphs represent interconnected structures prevalent in a myriad of real-world scenarios. Effective graph analytics, such as graph learning methods, enables users to gain profound insights from graph data, underpinning various tasks…

Machine Learning · Computer Science 2023-08-30 Zemin Liu , Yuan Li , Nan Chen , Qian Wang , Bryan Hooi , Bingsheng He

This volume contains the post-proceedings of the Fourteenth and the Fifteenth International Workshops on Graph Computation Models (GCM 2023 and 2024). The workshops took place in Leicester, UK on 18th July 2023 and Enschede, the Netherlands…

Logic in Computer Science · Computer Science 2025-03-26 Jörg Endrullis , Dominik Grzelak , Tobias Heindel , Jens Kosiol

Ramanujan graphs have fascinating properties and history. In this paper we explore a parallel notion of Ramanujan digraphs, collecting relevant results from old and recent papers, and proving some new ones. Almost-normal Ramanujan digraphs…

Combinatorics · Mathematics 2020-10-14 Ori Parzanchevski

Heffter arrays were introduced by Archdeacon in 2015 as an interesting link between combinatorial designs and topological graph theory. Since the initial paper on this topic, there has been a good deal of interest in Heffter arrays as well…

Combinatorics · Mathematics 2022-09-29 A. Pasotti , J. H. Dinitz

We construct an infinite family of 6-regular graphs $\{G_n\}_{n\ge 3}$ by taking $n$ copies of the Petersen graph and wiring corresponding vertices according to an $n$-cycle permutation. Each $G_n$ has $10n$ vertices, $30n$ edges, and…

Combinatorics · Mathematics 2026-03-18 Stuart E. Anderson

The paper discusses quantum graphs with a vertex coupling which interpolates between the common one of the $\delta$ type and a coupling introduced recently by two of the authors which exhibits a preferred orientation. Describing the…

Mathematical Physics · Physics 2018-06-11 Pavel Exner , Ondřej Turek , Miloš Tater

This is an expository paper extending the tutorial talk at the MATRIX Workshop on Uniqueness and Discernment in Graph Polynomials in October 2023. The explanation is mainly based on the paper "Partial Duality of Hypermaps" by S.Chmutov and…

Geometric Topology · Mathematics 2024-04-09 Sergei Chmutov

Link prediction in complex networks has attracted considerable attention from interdisciplinary research communities, due to its ubiquitous applications in biological networks, social networks, transportation networks, telecommunication…

Social and Information Networks · Computer Science 2020-12-22 Ece C. Mutlu , Toktam A. Oghaz , Amirarsalan Rajabi , Ivan Garibay

The vertices of an interval graph represent intervals over a real line where overlapping intervals denote that their corresponding vertices are adjacent. This implies that the vertices are measurable by a metric and there exists a linear…

Physics and Society · Physics 2015-03-26 Chuan Wen Loe , Henrik Jeldtoft Jensen

Inspired by the recent pioneering work, dubbed "The Ramanujan Machine" by Raayoni et al. (arXiv:1907.00205), we (automatically) [rigorously] prove some of their conjectures regarding the exact values of some specific infinite continued…

Number Theory · Mathematics 2020-05-27 Robert Dougherty-Bliss , Doron Zeilberger

Recently, many systems for graph analysis have been developed to address the growing needs of both industry and academia to study complex graphs. Insight into the practical uses of graph analysis will allow future developments of such…

Social and Information Networks · Computer Science 2018-07-03 Tim Hegeman , Alexandru Iosup

This paper presents an approach to summing a few families of infinite series involving hyperbolic functions, some of which were first studied by Ramanujan. The key idea is based on their contour integral representations and residue…

Number Theory · Mathematics 2024-09-27 Ce Xu , Jianqiang Zhao

The work in this thesis concerns the investigation of eigenvalues of the Laplacian matrix, normalized Laplacian matrix, signless Laplacian matrix and distance signless Laplacian matrix of graphs. In Chapter 1, we present a brief…

Combinatorics · Mathematics 2021-07-21 Bilal A. Rather

The purpose of this note is to explain the structure, general strategy, and main ideas of the proof in the work of Huang, McKenzie, and Yau (2024) on the Ramanujan property and edge universality of random regular graphs. The core of the…

Probability · Mathematics 2026-02-03 Jiaoyang Huang , Horng-Tzer Yau