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相关论文: Unmixed bipartite graphs

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Unmixed bipartite graphs have been characterized by Ravadra and Villarreal independently. Our aim in this paper is to characterize unmixed r-partite graphs under a certain condition, witch is a generalization of villarreal's theorem on…

组合数学 · 数学 2015-11-03 Reza Jafarpoure Golzari , Rashid Zaare-Nahandi

A classification is given of all the countable homogeneous ordered bipartite graphs.

组合数学 · 数学 2024-01-17 J. K. Truss

Using the theory of combinatorial species, we compute the cycle index for bipartite graphs, which we use to count unlabeled bipartite graphs and bipartite blocks.

组合数学 · 数学 2015-09-14 Andrew Gainer-Dewar , Ira M. Gessel

In this paper, we completely characterize the niche graphs of bipartite tournaments and find their interesting properties.

组合数学 · 数学 2018-10-15 Soogang Eoh , Jihoon Choi , Suh-Ryung Kim , Miok Oh

For an unmixed bipartite graph $G$ we consider the lattice of vertex covers $\mathcal{L}_G$ and compute depth, projective dimension and extremal Betti-numbers of $R/I(G)$ in terms of this lattice.

交换代数 · 数学 2009-01-21 Fatemeh Mohammadi , Somayeh Moradi

In this paper, we characterize all unmixed d-uniform r-partite hypergraphs under a certain condition. Also we give a necessary condition for unmixedness in d-uniform hypergraphs with a perfect matching of size n. Finally we give a…

交换代数 · 数学 2016-10-04 Reza Jafarpour-Golzari , Rashid Zaare-Nahandi

We introduce a new notation for representing labeled regular bipartite graphs of arbitrary degree. Several enumeration problems for labeled and unlabeled regular bipartite graphs have been introduced. A general algorithm for enumerating all…

离散数学 · 计算机科学 2015-12-31 Vivek S. Nittoor

We show that the independent set sequence of a bipartite graph need not be unimodal.

组合数学 · 数学 2013-01-10 Arnab Bhattacharyya , Jeff Kahn

Motivated by the concept of well-covered graphs, we define a graph to be well-bicovered if every vertex-maximal bipartite subgraph has the same order (which we call the bipartite number). We first give examples of them, compare them with…

组合数学 · 数学 2019-09-18 Wayne Goddard , Kirsti Kuenzel , Eileen Melville

We give a combinatorial characterization of graphs whose normalized Laplacian has three distinct eigenvalues. Strongly regular graphs and complete bipartite graphs are examples of such graphs, but we also construct more exotic families of…

组合数学 · 数学 2012-02-15 Edwin R. van Dam , Gholamreza Omidi

The correspondence between unmixed bipartite graphs and sublattices of the oolean lattice is discussed. By using this correspondence, we show the existence of squarefree quadratic initial ideals of toric ideals arising from minimal vertex…

交换代数 · 数学 2019-01-11 Juergen Herzog , Takayuki Hibi , Hidefumi Ohsugi

Classical spectral graph theory characterizes graphs with logarithmic mixing time. In this work, we present a combinatorial characterization of graphs with constant mixing time. The combinatorial characterization is based on the small-set…

数据结构与算法 · 计算机科学 2025-12-02 Lap Chi Lau , Raymond Liu

In this paper, we classify the connected non-bipartite integral graphs with spectral radius three.

组合数学 · 数学 2011-06-23 Taeyoung Chung , Jack Koolen , Yoshio Sano , Tetsuji Taniguchi

This paper deals with the problem of finding totally antimagic total labelings of complete bipartite graphs. We prove that complete bipartite graphs are totally antimagic total graphs. We also show that the join of complete bipartite graphs…

组合数学 · 数学 2016-08-25 Abolape D. Akwu , Deborah O. A. Ajayi

In this paper we consider bi-Cohen-Macaulay graphs, and give a complete classification of such graphs in the case they are bipartite or chordal. General bi-Cohen-Macaulay graphs are classified up to separation. The inseparable…

交换代数 · 数学 2015-08-31 Jürgen Herzog , Ahad Rahimi

The total matching polytope generalizes the stable set polytope and the matching polytope. In this paper, we first propose new facet-defining inequalities for the total matching polytope. We then give an exponential-sized, non-redundant…

离散数学 · 计算机科学 2023-12-29 Yuri Faenza , Luca Ferrarini

This paper is a survey on Extremal Graph Theory, primarily focusing on the case when one of the excluded graphs is bipartite. On one hand we give an introduction to this field and also describe many important results, methods, problems, and…

组合数学 · 数学 2013-07-02 Zoltán Füredi , Miklós Simonovits

A split graph is a graph whose vertices can be partitioned into a clique and a stable set. We investigate the combinatorial species of split graphs, providing species-theoretic generalizations of enumerative results due to B\'ina and…

组合数学 · 数学 2019-07-16 Justin M. Troyka

It is not hard to find many complete bipartite graphs which are not determined by their spectra. We show that the graph obtained by deleting an edge from a complete bipartite graph is determined by its spectrum. We provide some graphs, each…

组合数学 · 数学 2016-01-27 Chia-an Liu , Chih-wen Weng

We classify which complete multipartite graphs are intrinsically chiral.

几何拓扑 · 数学 2013-03-22 Erica Flapan , Will Fletcher
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