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Finding the maximum clique is a known NP-Complete problem and it is also hard to approximate. This work proposes two efficient algorithms to obtain it. Nevertheless, the first one is able to fins the maximum for some special cases, while…

Data Structures and Algorithms · Computer Science 2012-02-21 José Ignacio Alvarez-Hamelin

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

We study thresholds for the appearance of a 2-core in random hypergraphs that are a mixture of a constant number of random uniform hypergraphs each with a linear number of edges but with different edge sizes. For the case of two overlapping…

Data Structures and Algorithms · Computer Science 2012-04-11 Michael Rink

A (unit) disk graph is the intersection graph of closed (unit) disks in the plane. Almost three decades ago, an elegant polynomial-time algorithm was found for \textsc{Maximum Clique} on unit disk graphs [Clark, Colbourn, Johnson; Discrete…

Computational Geometry · Computer Science 2018-03-01 Édouard Bonnet , Panos Giannopoulos , Eun Jung Kim , Paweł Rzążewski , Florian Sikora

Large real-world graphs tend to be sparse, but they often contain many densely connected subgraphs and exhibit high clustering coefficients. While recent random graph models can capture this sparsity, they ignore the local density, or vice…

Methodology · Statistics 2019-07-18 Sinead A. Williamson , Mauricio Tec

Given a graph $F$, we consider the problem of determining the densest possible pseudorandom graph that contains no copy of $F$. We provide an embedding procedure that improves a general result of Conlon, Fox, and Zhao which gives an upper…

Combinatorics · Mathematics 2024-11-20 Xizhi Liu , Dhruv Mubayi , David Munhá Correia

In 1966, Erd\H{o}s, Goodman, and P\'osa proved that $\lfloor n^2/4 \rfloor$ cliques are sufficient to cover all edges in any $n$-vertex graph, with tightness achieved by the balanced complete bipartite graph. This result was generalized by…

Combinatorics · Mathematics 2025-06-13 Yihan Chen , Jialin He , Tianying Xie

Here we prove that a graph without some three induced subgraphs has chromatic number at the most equal to its maximum clique size plus one. Further we show that the bounds are tight and give examples to show that each of the three forbidden…

Combinatorics · Mathematics 2016-07-29 Medha Dhurandhar

We consider a problem introduced by Feige, Gamarnik, Neeman, R\'acz and Tetali [2020], that of finding a large clique in a random graph $G\sim G(n,\frac{1}{2})$, where the graph $G$ is accessible by queries to entries of its adjacency…

Data Structures and Algorithms · Computer Science 2021-12-14 Uriel Feige , Tom Ferster

For a graph $G$, let $cp(G)$ denote the minimum number of cliques of $G$ needed to cover the edges of $G$ exactly once. Similarly, let $bp_k(G)$ denote the minimum number of bicliques (i.e. complete bipartite subgraphs of $G$) needed to…

Combinatorics · Mathematics 2020-05-07 Dhruv Rohatgi , John C. Urschel , Jake Wellens

A disk graph is an intersection graph of disks in $\mathbb{R}^2$. Determining the computational complexity of finding a maximum clique in a disk graph is a long-standing open problem. In 1990, Clark, Colbourn, and Johnson gave a…

Computational Geometry · Computer Science 2024-07-17 J. Mark Keil , Debajyoti Mondal

We study the fine-grained complexity of evaluating Boolean Conjunctive Queries and their generalization to sum-of-product problems over an arbitrary semiring. For these problems, we present a general semiring-oblivious reduction from the…

Databases · Computer Science 2023-05-11 Austen Z. Fan , Paraschos Koutris , Hangdong Zhao

The NP-hard Maximum Planar Subgraph problem asks for a planar subgraph $H$ of a given graph $G$ such that $H$ has maximum edge cardinality. For more than two decades, the only known non-trivial exact algorithm was based on integer linear…

Data Structures and Algorithms · Computer Science 2018-06-22 Markus Chimani , Tilo Wiedera

We consider the question of how many edge-disjoint near-maximal cliques may be found in the dense Erd\H{o}s-R\'enyi random graph $G(n,p)$. Recently Acan and Kahn showed that the largest such family contains only $O(n^2/(\log{n})^3)$…

Combinatorics · Mathematics 2025-10-15 Simon Griffiths , Letícia Mattos

We introduce and study the problem of optimizing arbitrary functions over degree sequences of hypergraphs and multihypergraphs. We show that over multihypergraphs the problem can be solved in polynomial time. For hypergraphs, we show that…

Optimization and Control · Mathematics 2018-08-21 Antoine Deza , Asaf Levin , Syed M. Meesum , Shmuel Onn

A simple graph on $n$ vertices may contain a lot of maximum cliques. But how many can it potentially contain? We will define prime and composite graphs, and we will show that if $n \ge 15$, then the grpahs with the maximum number of maximum…

Combinatorics · Mathematics 2025-12-17 Dániel Pfeifer

Finding "densely connected clusters" in a graph is in general an important and well studied problem in the literature \cite{Schaeffer}. It has various applications in pattern recognition, social networking and data mining…

Machine Learning · Statistics 2011-04-28 Samet Oymak , Babak Hassibi

Motivated in part by various sequences of graphs growing under random rules (like internet models), convergent sequences of dense graphs and their limits were introduced by Borgs, Chayes, Lov\'asz, S\'os and Vesztergombi and by Lov\'asz and…

Combinatorics · Mathematics 2009-05-26 C. Borgs , J. Chayes , L. Lovász , V. T. Sós , K. Vesztergombi

Finding a maximum clique in a given graph is one of the fundamental NP-hard problems. We compare two multi-core thread-parallel adaptations of a state-of-the-art branch and bound algorithm for the maximum clique problem, and provide a novel…

Distributed, Parallel, and Cluster Computing · Computer Science 2014-09-05 Ciaran McCreesh , Patrick Prosser

In this paper, we consider an optimal control problem of an ordinary differential inclusion governed by the hypergraph Laplacian, which is defined as a subdifferential of a convex function and then is a set-valued operator. We can assure…

Optimization and Control · Mathematics 2024-09-04 Takeshi Fukao , Masahiro Ikeda , Shun Uchida
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