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The isomorphism problem for planar graphs is known to be efficiently solvable. For planar 3-connected graphs, the isomorphism problem can be solved by efficient parallel algorithms, it is in the class $AC^1$. In this paper we improve the…

Data Structures and Algorithms · Computer Science 2008-02-21 Thomas Thierauf , Fabian Wagner

We show that clustered planarity with overlapping clusters as introduced by Didimo et al. can be solved in polynomial time if each cluster induces a connected subgraph. It can be solved in linear time if the set of clusters is the union of…

Computational Geometry · Computer Science 2016-09-16 Jan Christoph Athenstädt , Sabine Cornelsen

Semi-supervised clustering is a basic problem in various applications. Most existing methods require knowledge of the ideal cluster number, which is often difficult to obtain in practice. Besides, satisfying the must-link constraints is…

Optimization and Control · Mathematics 2025-03-07 Wei Liu , Xin Liu , Michael K. Ng , Zaikun Zhang

We propose a node clustering method for time-varying graphs based on the assumption that the cluster labels are changed smoothly over time. Clustering is one of the fundamental tasks in many science and engineering fields including signal…

Machine Learning · Computer Science 2023-05-12 Katsuki Fukumoto , Koki Yamada , Yuichi Tanaka , Hoi-To Wai

Relationship between agents can be conveniently represented by graphs. When these relationships have different modalities, they are better modelled by multilayer graphs where each layer is associated with one modality. Such graphs arise…

Machine Learning · Statistics 2021-03-05 Guillaume Braun , Hemant Tyagi , Christophe Biernacki

Graph-based clustering methods have demonstrated the effectiveness in various applications. Generally, existing graph-based clustering methods first construct a graph to represent the input data and then partition it to generate the…

Machine Learning · Computer Science 2019-12-17 Yuheng Jia , Hui Liu , Junhui Hou , Sam Kwong

This paper studies the problem of graph-level clustering, which is a novel yet challenging task. This problem is critical in a variety of real-world applications such as protein clustering and genome analysis in bioinformatics. Recent years…

Machine Learning · Computer Science 2023-03-09 Wei Ju , Yiyang Gu , Binqi Chen , Gongbo Sun , Yifang Qin , Xingyuming Liu , Xiao Luo , Ming Zhang

Consider the following two ways to colour the vertices of a graph where the requirement that adjacent vertices get distinct colours is relaxed. A colouring has "defect" $d$ if each monochromatic component has maximum degree at most $d$. A…

Combinatorics · Mathematics 2018-03-22 David R. Wood

Clustering a graph when the clusters can overlap can be seen from three different angles: We may look for cliques that cover the edges of the graph with bounded overlap, we may look to add or delete few edges to uncover the cluster…

Data Structures and Algorithms · Computer Science 2024-04-04 Alexander Firbas , Alexander Dobler , Fabian Holzer , Jakob Schafellner , Manuel Sorge , Anaïs Villedieu , Monika Wißmann

We introduce a dynamic version of the NP-hard graph problem Cluster Editing. The essential point here is to take into account dynamically evolving input graphs: Having a cluster graph (that is, a disjoint union of cliques) that represents a…

Discrete Mathematics · Computer Science 2018-12-12 Junjie Luo , Hendrik Molter , André Nichterlein , Rolf Niedermeier

Graph clustering is a central topic in unsupervised learning with a multitude of practical applications. In recent years, multi-view graph clustering has gained a lot of attention for its applicability to real-world instances where one has…

Machine Learning · Computer Science 2024-06-10 Vincent Cohen-Addad , Tommaso d'Orsi , Silvio Lattanzi , Rajai Nasser

Beyond-planarity focuses on the study of geometric and topological graphs that are in some sense nearly-planar. Here, planarity is relaxed by allowing edge crossings, but only with respect to some local forbidden crossing configurations.…

Discrete Mathematics · Computer Science 2017-12-29 Patrizio Angelini , Michael A. Bekos , Michael Kaufmann , Maximilian Pfister , Torsten Ueckerdt

We study {\sc Cluster Edge Modification} problems with constraints on the size of the clusters. A graph $G$ is a cluster graph if every connected component of $G$ is a clique. In a typical {\sc Cluster Edge Modification} problem such as the…

Data Structures and Algorithms · Computer Science 2024-09-05 Jayakrishnan Madathil , Kitty Meeks

In the Segment Intersection Graph Representation Problem, we want to represent the vertices of a graph as straight line segments in the plane such that two segments cross if and only if there is an edge between the corresponding vertices.…

Computational Geometry · Computer Science 2025-02-25 Simon D. Fink , Matthias Pfretzschner , Peter Stumpf

This paper considers the problem of clustering a partially observed unweighted graph---i.e., one where for some node pairs we know there is an edge between them, for some others we know there is no edge, and for the remaining we do not know…

Machine Learning · Computer Science 2014-07-25 Yudong Chen , Ali Jalali , Sujay Sanghavi , Huan Xu

Graph clustering is a fundamental problem that has been extensively studied both in theory and practice. The problem has been defined in several ways in literature and most of them have been proven to be NP-Hard. Due to their high practical…

Social and Information Networks · Computer Science 2012-03-27 Sumit Singh

Modern graph or network datasets often contain rich structure that goes beyond simple pairwise connections between nodes. This calls for complex representations that can capture, for instance, edges of different types as well as so-called…

Social and Information Networks · Computer Science 2020-02-19 Ilya Amburg , Nate Veldt , Austin R. Benson

A graph is near-planar if it can be obtained from a planar graph by adding an edge. We show the surprising fact that it is NP-hard to compute the crossing number of near-planar graphs. A graph is 1-planar if it has a drawing where every…

Computational Geometry · Computer Science 2012-03-28 Sergio Cabello , Bojan Mohar

Spectral clustering is popular among practitioners and theoreticians alike. While performance guarantees for spectral clustering are well understood, recent studies have focused on enforcing ``fairness'' in clusters, requiring them to be…

Machine Learning · Computer Science 2022-09-27 Shubham Gupta , Ambedkar Dukkipati

This work considers clustering nodes of a largely incomplete graph. Under the problem setting, only a small amount of queries about the edges can be made, but the entire graph is not observable. This problem finds applications in…

Machine Learning · Computer Science 2021-10-04 Shahana Ibrahim , Xiao Fu