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Related papers: On the clique number of a strongly regular graph

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We consider mining dense substructures (maximal cliques) from an uncertain graph, which is a probability distribution on a set of deterministic graphs. For parameter 0 < {\alpha} < 1, we present a precise definition of an {\alpha}-maximal…

Data Structures and Algorithms · Computer Science 2014-10-23 Arko Provo Mukherjee , Pan Xu , Srikanta Tirthapura

We prove an upper bound of $n+9$ for the strong separation number of the complete graph $K_n$, and an upper bound of $n+1$ for its weak separation number. This improves on the previous best known bound of $(1+o(1))n$ for both cases.

Combinatorics · Mathematics 2026-03-25 George Kontogeorgiou , Maya Stein

The feasibility conditions obtained in a previous report are refined, and used to determine several infinite families of feasible parameters for strongly regular graphs with no triangles. The methods are also used to improve the lower bound…

Combinatorics · Mathematics 2009-11-13 Norman Biggs

We consider a variant of the clustering problem for a complete weighted graph. The aim is to partition the nodes into clusters maximizing the sum of the edge weights within the clusters. This problem is known as the clique partitioning…

Social and Information Networks · Computer Science 2023-09-15 Alexander Belyi , Stanislav Sobolevsky , Alexander Kurbatski , Carlo Ratti

It is known that non-isomorphic strongly regular graphs with the same parameters must be cospectral (have the same eigenvalues). In this paper, we investigate whether the spectra of higher order Laplacians associated with these graphs can…

Combinatorics · Mathematics 2025-08-11 Sebastian M. Cioabă , Krystal Guo , Chunxu Ji , Mutasim Mim

Generalized Tur\'an problems have been a central topic of study in extremal combinatorics throughout the last few decades. One such problem, maximizing the number of cliques of a fixed order in a graph with fixed number of vertices and…

Combinatorics · Mathematics 2021-06-10 Debsoumya Chakraborti , Da Qi Chen

Consider the family of all finite graphs with maximum degree $\Delta(G)<d$ and matching number $\nu(G)<m$. In this paper we give a new proof to obtain the exact upper bound for the number of edges in such graphs and also characterize all…

Combinatorics · Mathematics 2007-05-23 Niranjan Balachandran , Niraj Khare

We give variants of the Krein bound and the absolute bound for graphs with a spectrum similar to that of a strongly regular graph. In particular, we investigate what we call approximately strongly regular graphs. We apply our results to…

Combinatorics · Mathematics 2022-08-10 Ferdinand Ihringer

We show that a graph with $n$ vertices and vertex cover of size $k$ has at most $4^k + n$ potential maximal cliques. We also show that for each positive integer $k$, there exists a graph with vertex cover of size $k$, $O(k^2)$ vertices, and…

Combinatorics · Mathematics 2020-11-24 Tuukka Korhonen

Clique-width is a well-studied graph parameter. For graphs of bounded clique-width, many problems that are NP-hard in general can be polynomial-time solvable. The fact motivates several studies to investigate whether the clique-width of…

Data Structures and Algorithms · Computer Science 2022-02-01 Yu Nakahata

The inertia bound gives an upper bound on the independence number of a graph by considering the inertia of matrices corresponding to the graph. The bound is known to be tight for graphs on 10 or fewer vertices as well as for all perfect…

Combinatorics · Mathematics 2016-09-12 John Sinkovic

We prove an upper bound on the number of pairwise strongly cospectral vertices in a normal Cayley graph, in terms of the multiplicities of its eigenvalues. We use this to determine an explicit bound in Cayley graphs of $\mathbb{Z}_2^d$ and…

Combinatorics · Mathematics 2023-05-19 Arnbjörg Soffía Árnadóttir , Chris Godsil

In this paper, we present a sharp upper and lower bounds for the signless Laplacian spectral radius of graphs in terms of clique number. Moreover, the extremal graphs which attain the upper and lower bounds are characterized. In addition,…

Combinatorics · Mathematics 2012-09-17 Bian He , Ya-Lei Jin , Xiao-Dong Zhang

For a prime $p$ we define the Paley graph to be the graph with the set of vertices $\mathbb{Z}/p\mathbb{Z}$, and with edges connecting vertices whose sum is a quadratic residue. Paley graphs are notoriously difficult to study, particularly…

Number Theory · Mathematics 2016-03-03 Rudi Mrazović

This paper proposes a new algorithm for solving maximal cliques for simple undirected graphs using the theory of prime numbers. A novel approach using prime numbers is used to find cliques and ends with a discussion of the algorithm.

Data Structures and Algorithms · Computer Science 2007-05-23 Dhananjay D. Kulkarni , Shekhar Verma , Prashant

In extremal graph theory, the problem of finding the elements of a given class of graphs which contain the most cliques traces its routes back to Tur\'an's famous theorem. We consider the implications of the connectivity property of…

Combinatorics · Mathematics 2018-10-11 Corbin Groothuis

It is well known that $n/(n - \mu)$, where $\mu$ is the spectral radius of a graph with $n$ vertices, is a lower bound for the clique number. We conjecture that $\mu$ can be replaced in this bound with $\sqrt{s^+}$, where $s^+$ is the sum…

Combinatorics · Mathematics 2018-08-10 Clive Elphick , Pawel Wocjan

The indeque number of a graph is largest set of vertices that induce an independent set of cliques. We study the extremal value of this parameter for the class and subclasses of planar graphs, most notably for forests and graphs of…

Combinatorics · Mathematics 2025-09-08 Csaba Biró , Gabriel Collado , Oscar Zamora

In this paper we unify several existing regularity conditions for graphs, including strong regularity, $k$-isoregularity, and the $t$-vertex condition. We develop an algebraic composition/decomposition theory of regularity conditions. Using…

Combinatorics · Mathematics 2020-02-17 Christian Pech

In this article we construct a series of new infinite families of strongly regular graphs with the same parameters as the point-graphs of non-singular quadrics in PG(n,2).

Combinatorics · Mathematics 2016-06-20 S. G. Barwick , Wen-Ai Jackson , Tim Penttila