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In this paper, we give a polynomial-time algorithm for deciding whether an input bipartite graph admits a 2-layer fan-planar drawing, resolving an open problem posed in several papers since 2015.

Computational Geometry · Computer Science 2025-08-26 Yasuaki Kobayashi , Yuto Okada

Geometric modeling by constraints leads to large systems of algebraic equations. This paper studies bipartite graphs underlaid by systems of equations. It shows how these graphs make possible to polynomially decompose these systems into…

Discrete Mathematics · Computer Science 2014-05-26 Samy Ait-Aoudia , Roland Jegou , Dominique Michelucci

We study a parameter of bipartite graphs called readability, introduced by Chikhi et al. (Discrete Applied Mathematics, 2016) and motivated by applications of overlap graphs in bioinformatics. The behavior of the parameter is poorly…

Discrete Mathematics · Computer Science 2018-05-15 Rayan Chikhi , Vladan Jovicic , Stefan Kratsch , Paul Medvedev , Martin Milanic , Sofya Raskhodnikova , Nithin Varma

We present a generalization of the construction of graphs by Lubotzky, Phillips and Sarnak in their celebrated article "Ramanujan graphs". The new approach consists in using octonion algebras rather than quaternions. A key tool is the…

Combinatorics · Mathematics 2012-02-06 Xavier Dahan , Jean-Pierre Tillich

This article aims to provide exponential lower bounds on the number of non-isomorphic $k$-gonal biembeddings of the complete multipartite graph into orientable surfaces. For this purpose, we use the concept, introduced by Archdeacon in…

Combinatorics · Mathematics 2022-03-03 Simone Costa , Anita Pasotti

There have been researches on sufficient spectral conditions for Hamiltonian properties and path-coverable properties of graphs. Utilizing the Bondy-Chv\'atal closure, we provide a unified approach to study sufficient graph eigenvalue…

Combinatorics · Mathematics 2020-05-11 Muhuo Liu , Yang Wu , Hong-Jian Lai

In 2003, Fischermann et al. considered the maximum size of \textit{uniquely-dominatable} graphs, graphs whose dominating number is realized only by a unique dominating set. They conjectured a size bound and provide a general graph…

Combinatorics · Mathematics 2025-11-04 Garrison Koch , Darren Narayan

We study connections between expansion in bipartite graphs and efficient online matching modeled via several games. In the basic game, an opponent switches {\em on} and {\em off} nodes on the left side and, at any moment, at most $K$ nodes…

Data Structures and Algorithms · Computer Science 2024-07-09 Bruno Bauwens , Marius Zimand

We show that any $3$-connected cubic plane graph on $n$ vertices, with all faces of size at most $6$, can be made bipartite by deleting no more than $\sqrt{(p+3t)n/5}$ edges, where $p$ and $t$ are the numbers of pentagonal and triangular…

Combinatorics · Mathematics 2020-07-24 Diego Nicodemos , Matěj Stehlík

In this note we give a short proof that graphs having no linearly small F{\o}lner sets can be partitioned into a union of expanders. We use this fact to prove a partition result for graphs admitting linearly small maximal F{\o}lner sets and…

Combinatorics · Mathematics 2021-01-13 Federico Vigolo

Recently, there has been interest in representing single graphs by multiple drawings; for example, using graph stories, storyplans, or uncrossed collections. In this paper, we apply this idea to orthogonal graph drawing. Due to the…

The matching book thickness of a graph is the least number of pages in a book embedding such that each page is a matching. A graph is dispersable if its matching book thickness equals its maximum degree. Minimum page matching book…

Combinatorics · Mathematics 2024-04-16 Paul C. Kainen , Samuel S. Joslin , Shannon Overbay

We show that in a complex d-dimensional vector space, one can find O(d) bases whose elements form a 2-design. Such vector sets generalize the notion of a maximal collection of mutually unbiased bases (MUBs). MUBs have manifold applications…

Quantum Physics · Physics 2008-05-19 Gary McConnell , David Gross

A bipartite graph is {\em pseudo 2--factor isomorphic} if all its 2--factors have the same parity of number of circuits. In \cite{ADJLS} we proved that the only essentially 4--edge-connected pseudo 2--factor isomorphic cubic bipartite graph…

Combinatorics · Mathematics 2015-01-13 M. Abreu , D. Labbate , J. Sheehan

A graph is called $1$-planar if it admits a drawing in the plane such that each edge is crossed at most once. Let $G$ be a bipartite 1-planar graph with $n$ ($\ge 4$) vertices and $m$ edges. Karpov showed that $m\le 3n-8$ holds for even…

Combinatorics · Mathematics 2020-07-28 Yuanqiu Huang , Zhangdong Ouyang , Fengming Dong

In this paper we provide a method of finding possible numbers of shortest paths between two points in a space of compact sets in Euclidean space with Hausdorff distance. We also prove that there cannot be some of the numbers of shortest…

Metric Geometry · Mathematics 2013-12-10 Zakhar Ovsyannikov

In this paper, we obtain new lower and upper bounds for the problem of bipartite biregular cages. Moreover, for girth $6$, we give the exact parameters of the $(m,n;6)$-bipartite biregular cages when $n\equiv -1$ $\pmod m$ using the…

Combinatorics · Mathematics 2023-10-19 Gabriela Araujo-Pardo , György Kiss , Tamás Szönyi

We compute the quadratic embedding constant for complete bipartite graphs with disjoint edges removed. Moreover, we study the quadratic embedding property for theta graphs, i.e., graphs consisting of three paths with common initial points…

Combinatorics · Mathematics 2024-10-02 Wojciech Młotkowski , Marek Skrzypczyk , Michał Wojtylak

The extension complexity $\mathsf{xc}(P)$ of a polytope $P$ is the minimum number of facets of a polytope that affinely projects to $P$. Let $G$ be a bipartite graph with $n$ vertices, $m$ edges, and no isolated vertices. Let…

Discrete Mathematics · Computer Science 2017-06-06 Manuel Aprile , Yuri Faenza , Samuel Fiorini , Tony Huynh , Marco Macchia

Let $K_{m[n]}$ be the complete multipartite graph with $m$ parts, while each part contains $n$ vertices. The orientably-regular embeddings of complete graphs $K_{m[1]}$ have been determined by Biggs (1971) \cite{Big1}, James and Jones…

Combinatorics · Mathematics 2012-06-12 Shaofei Du , Junyang Zhang
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