Bipartite biregular Moore graphs

被引：2

作者：

Araujo-Pardo, G. ^{[1
]}

Dalfo, C. ^{[2
]}

Fiol, M. A. ^{[3
]}

Lopez, N. ^{[4
]}

机构：

[1] Univ Nacl Autonoma Mexico, Inst Matemat, Mexico City, DF, Mexico

[2] Univ Lleida, Dept Matemat, Catalonia, Barcelona, Spain

[3] Univ Politecn Cataluna, Barcelona Grad Sch Math, Inst Matemat UPC BarcelonaTech IMTech, Dept Matemat, Barcelona, Spain

[4] Univ Lleida, Dept Matemat, Lleida, Spain

来源：

DISCRETE MATHEMATICS | 2021年 / 344卷 / 11期

关键词：

Bipartite biregular graphs; Moore bound; Diameter; Adjacency spectrum;

D O I：

10.1016/j.disc.2021.112582

中图分类号：

O1 [数学];

学科分类号：

0701 ; 070101 ;

摘要：

A bipartite graph G = (V, E) with V = V-1 boolean OR V-2 is biregular if all the vertices of a stable set V-i have the same degree r(i) for i = 1, 2. In this paper, we give an improved new Moore bound for an infinite family of such graphs with odd diameter. This problem was introduced in 1983 by Yebra, Fiol, and Fabrega. Besides, we propose some constructions of bipartite biregular graphs with diameter d and large number of vertices N(r(1), r(2); d), together with their spectra. In some cases of diameters d = 3, 4, and 5, the new graphs attaining the Moore bound are unique up to isomorphism. (C) 2021 The Author(s). Published by Elsevier B.V.

引用

页数：12

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