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We introduce a family of graph parameters, called induced multipartite graph parameters, and study their computational complexity. First, we consider the following decision problem: an instance is an induced multipartite graph parameter $p$…

Computational Complexity · Computer Science 2023-05-05 Ryan L. Mann , Luke Mathieson , Catherine Greenhill

For a graph $G$ of order $n$ and with eigenvalues $\lambda_1\geqslant\cdots\geqslant\lambda_n$, the HL-index $R(G)$ is defined as $R(G) ={\max}\left\{|\lambda_{\lfloor(n+1)/2\rfloor}|, |\lambda_{\lceil(n+1)/2\rceil}|\right\}.$ We show that…

Combinatorics · Mathematics 2013-12-11 Bojan Mohar , Behruz Tayfeh-Rezaie

A \emph{directional labeling} of an edge $\emph{uv}$ in a graph $G=(V,E)$ by an ordered pair $ab$ is a labeling of the edge $uv$ such that the label on $uv$ in the direction from $u$ to $v$ is $\ell(uv)=ab$, and $\ell(vu)=ba$. New…

Combinatorics · Mathematics 2013-04-02 E. Sampathkumar , M. A. Sriraj

A theory of orientation on gain graphs (voltage graphs) is developed to generalize the notion of orientation on graphs and signed graphs. Using this orientation scheme, the line graph of a gain graph is studied. For a particular family of…

Combinatorics · Mathematics 2015-06-17 Nathan Reff

Genevois introduced and investigated mediangle graphs as a common generalization of median graphs (1-sekeleta of CAT(0) cube complexes) and Coxeter graphs (Cayley graphs of Coxeter systems) and studied groups acting on them. He asked if…

Combinatorics · Mathematics 2025-12-10 Victor Chepoi , Kolja Knauer

We study the problem of generating graphs with prescribed degree sequences for bipartite, directed, and undirected networks. We first propose a sequential method for bipartite graph generation and establish a necessary and sufficient…

Methodology · Statistics 2026-03-13 Tong Sun , Jianshu Hao , Michael C. Fu , Guangxin Jiang

It has been known since 1991 that the problem of recognizing grid intersection graphs is NP-complete. Here we use a modified argument of the above result to show that even if we restrict to the class of unit grid intersection graphs…

Combinatorics · Mathematics 2013-06-11 Irina Mustaţă , Martin Pergel

Graphs derived from groups are a widely studied class of graphs, motivated by their highly symmetric structure. In particular, G-graphs offer an easy and interesting alternative construction of semi-symmetric graphs. After recalling the…

Combinatorics · Mathematics 2016-11-25 David Ellison , Ruxandra Marinescu-Ghemeci , Cerasela Tanasescu

Let $G$ be a bipartite graph on $n$ vertices with the Laplacian matrix $L_G$. When $G$ is a tree, inequalities involving coefficients of immanantal polynomials of $L_G$ are known as we go up $GTS_n$ poset of unlabelled trees with $n$…

Combinatorics · Mathematics 2023-08-01 Mukesh Kumar Nagar

We consider the problem of finding all allowed edges in a bipartite graph $G=(V,E)$, i.e., all edges that are included in some maximum matching. We show that given any maximum matching in the graph, it is possible to perform this…

Discrete Mathematics · Computer Science 2011-07-26 Tamir Tassa

Topological drawings are natural representations of graphs in the plane, where vertices are represented by points, and edges by curves connecting the points. Topological drawings of complete graphs and of complete bipartite graphs have been…

Computational Geometry · Computer Science 2017-02-10 Jean Cardinal , Stefan Felsner

Recently, graph neural networks have been adopted in a wide variety of applications ranging from relational representations to modeling irregular data domains such as point clouds and social graphs. However, the space of graph neural…

Machine Learning · Computer Science 2018-12-14 Marcel Nassar

The disjoint convex obstacle number of a graph G is the smallest number h such that there is a set of h pairwise disjoint convex polygons (obstacles) and a set of n points in the plane (corresponding to V(G)) so that a vertex pair uv is an…

Discrete Mathematics · Computer Science 2011-09-13 Radoslav Fulek , Noushin Saeedi , Deniz Sarioz

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

Graph convexity spaces have been studied in many contexts. In particular, some studies are devoted to determine if a graph equipped with a convexity space is a {\em convex geometry}. It is well known that chordal and Ptolemaic graphs can be…

Combinatorics · Mathematics 2022-03-14 Marisa Gutierrez , Fábio Protti , Silvia B. Tondato

Motivated by recent extensive studies on Wenger graphs, we introduce a new infinite class of bipartite graphs of the similar type, called linearized Wenger graphs. The spectrum, diameter and girth of these linearized Wenger graphs are…

Combinatorics · Mathematics 2014-12-02 Xiwang Cao , Mei Lu , Daqing Wan , Li-Ping Wang , Qiang Wang

Bipartite graph embedding has recently attracted much attention due to the fact that bipartite graphs are widely used in various application domains. Most previous methods, which adopt random walk-based or reconstruction-based objectives,…

Social and Information Networks · Computer Science 2020-12-11 Jiangxia Cao , Xixun Lin , Shu Guo , Luchen Liu , Tingwen Liu , Bin Wang

We show that if the two parts of a finite bipartite graph have the same degree sequence, then there is a bipartite graph, with the same degree sequences, which is symmetric, in that it has an involutive graph automorphism that interchanges…

Combinatorics · Mathematics 2014-07-07 Grant Cairns , Stacey Mendan

It is well known that a plane graph is Eulerian if and only if its geometric dual is bipartite. We extend this result to partial duals of plane graphs. We then characterize all bipartite partial duals of a plane graph in terms of oriented…

Combinatorics · Mathematics 2013-11-18 Stephen Huggett , Iain Moffatt

This paper is the first from a series of papers that provide a characterization of maximum packings of $T$-cuts in bipartite graphs. Given a connected graph, a set $T$ of an even number of vertices, and a minimum $T$-join, an edge weighting…

Combinatorics · Mathematics 2022-02-21 Nanao Kita