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The book embedding of a graph $G$ is to place the vertices of $G$ on the spine and draw the edges to the pages so that the edges in the same page do not cross with each other. A book embedding is matching if the vertices in the same page…

Combinatorics · Mathematics 2021-07-05 Zeling Shao , Yanqing Liu , Zhiguo Li

A graph is called dispersable if it has a book embedding in which each page has maximum degree 1 and the number of pages is the maximum degree. Bernhart and Kainen conjectured every k-regular bipartite graph is dispersable. Forty years…

Combinatorics · Mathematics 2021-07-13 Paul C. Kainen , Shannon Overbay

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

In a dispersable book embedding, the vertices of a given graph $G$ must be ordered along a line l, called spine, and the edges of G must be drawn at different half-planes bounded by l, called pages of the book, such that: (i) no two edges…

Discrete Mathematics · Computer Science 2018-03-28 Jawaherul Md. Alam , Michael A. Bekos , Martin Gronemann , Michael Kaufmann , Sergey Pupyrev

In this paper, the dispersability of the Cartesian graph bundle over two cycles is completely solved. We show the Cartesian graph bundle $G$ over two cycles is dispersable if $G$ is bipartite; otherwise, $G$ is nearly dispersable.

Combinatorics · Mathematics 2024-05-28 Zeling Shao , Xiaoxiang Yu , Zhiguo Li

We prove that a strongly connected balanced bipartite directed graph of order $2a\geq 6$ with partite sets $X$ and $Y$ contains cycles of every length $2, 4, \ldots , 2a$, provided $d(x)+d(y)\geq 3a$ for every pair of vertices $x$, $y$…

Combinatorics · Mathematics 2018-01-17 Samvel Kh. Darbinyan

R. Wang (Discrete Mathematics and Theoretical Computer Science, vol. 19(3), 2017) proposed the following problem. \textbf{Problem.} Let $D$ be a strongly connected balanced bipartite directed graph of order $2a\geq 8$. Suppose that…

Combinatorics · Mathematics 2018-07-13 Samvel Kh. Darbinyan , Iskandar A. Karapetyan

Kang and Park recently showed that every cubic (loopless) multigraph is incidence 6-choosable [On incidence choosability of cubic graphs. \emph{arXiv}, April 2018]. Equivalently, every bipartite graph obtained by subdividing once every edge…

Combinatorics · Mathematics 2018-08-06 Petru Valicov

In this paper, we give the classification of circulant graphs $C(\mathbb{Z}_{n},S)$ with $|S|=2$ and completely solve the dispersability of circulant graphs $C(\mathbb{Z}_{n},\{1, k\})$.

Combinatorics · Mathematics 2023-10-11 Xiaoxiang Yu , Zeling Shao , Zhiguo Li

In this paper, we give a lengthy proof of a small result! A graph is bisplit if its vertex set can be partitioned into three stable sets with two of them inducing a complete bipartite graph. We prove that these graphs satisfy the…

Discrete Mathematics · Computer Science 2023-06-22 Laurent Beaudou , Giacomo Kahn , Matthieu Rosenfeld

The regular embeddings of complete bipartite graphs $K_{n,n}$ in orientable surfaces are classified and enumerated, and their automorphism groups and combinatorial properties are determined. The method depends on earlier classifications in…

Combinatorics · Mathematics 2014-02-26 Gareth A. Jones

Bourgain and Yehudayoff recently constructed $O(1)$-monotone bipartite expanders. By combining this result with a generalisation of the unraveling method of Kannan, we construct 3-monotone bipartite expanders, which is best possible. We…

Combinatorics · Mathematics 2016-02-09 Vida Dujmović , Anastasios Sidiropoulos , David R. Wood

A bicirculant is a regular, $d$-valent graph that admits a semiregular automorphism of order $m$ having two vertex-orbits of size $m$. The vertices of each orbit induce a circulant graph of order $m$ and the remaining edges span a regular…

Combinatorics · Mathematics 2025-08-28 Simona Bonvicini , Tomaž Pisanski , Arjana Žitnik

We prove two sharp sufficient conditions for hamiltonian cycles in balanced bipartite directed graph. Let $D$ be a strongly connected balanced bipartite directed graph of order $2a$. Let $x,y$ be distinct vertices in $D$. $\{x,y\}$…

Combinatorics · Mathematics 2016-05-02 Samvel Kh. Darbinyan

In a closed 2-cell embedding of a graph each face is homeomorphic to an open disk and is bounded by a cycle in the graph. The Orientable Strong Embedding Conjecture says that every 2-connected graph has a closed 2-cell embedding in some…

Combinatorics · Mathematics 2009-11-17 M. N. Ellingham , Xiaoya Zha

We prove that a strongly connected balanced bipartite digraph $D$ of order $2a$, $a\geq3$, satisfying $d(u)+d(v)\geq 3a$ for every pair of vertices $u,v$ with a common in-neighbour or a common out-neighbour, is either bipancyclic or a…

Combinatorics · Mathematics 2018-05-25 Janusz Adamus

Let $n\geq 6,k\geq 0$ be two integers. Let $H$ be a graph of order $n$ with $k$ components, each of which is an even cycle of length at least $6$ and $G$ be a bipartite graph with bipartition $(X,Y)$ such that $|X|=|Y|\geq n/2$. In this…

Combinatorics · Mathematics 2019-04-04 Shengning Qiao , Bing Chen

We prove a bifurcation result of uniformly-rotating/stationary non-trivial vortex sheets near the circular distribution for a model of two irrotational fluids with same density taking into account surface tension effects. As bifurcation…

Analysis of PDEs · Mathematics 2024-10-17 Federico Murgante , Emeric Roulley , Stefano Scrobogna

This paper initiates the study of circular orderability of $3$-manifold groups, motivated by the L-space conjecture. We show that a compact, connected, $\mathbb{P}^2$-irreducible $3$-manifold has a circularly orderable fundamental group if…

Geometric Topology · Mathematics 2025-05-21 Idrissa Ba , Adam Clay

Let $k$ be a positive integer. Let $G$ be a balanced bipartite graph of order $2n$ with bipartition $(X, Y)$, and $S$ a subset of $X$. Suppose that every pair of nonadjacent vertices $(x,y)$ with $x\in S, y\in Y$ satisfies $d(x)+d(y)\geq…

Combinatorics · Mathematics 2020-11-24 Suyun Jiang , Jin Yan
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