Upper bounds on the number of perfect matchings and directed 2-factors in graphs with given number of vertices and edges

被引:7
|
作者
Aaghabali, M. [3 ]
Akbari, S. [1 ,4 ]
Friedland, S. [2 ]
Markstroem, K. [5 ]
Tajfirouz, Z. [3 ]
机构
[1] Sharif Univ Technol, Dept Math Sci, Tehran, Iran
[2] Univ Illinois, Dept Math Stat & Comp Sci, Chicago, IL USA
[3] Univ Zanjan, Dept Math, Zanjan, Iran
[4] Inst Studies Theoret Phys & Math IPM, Tehran, Iran
[5] Umea Univ, Dept Math & Math Stat, S-90187 Umea, Sweden
基金
美国国家科学基金会;
关键词
PERMANENT;
D O I
10.1016/j.ejc.2014.11.001
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
We give an upper bound on the number of perfect matchings in simple graphs with a given number of vertices and edges. We apply this result to give an upper bound on the number of 2-factors in a directed complete bipartite balanced graph on 2n vertices. The upper bound is sharp for even n. For odd n we state a conjecture on a sharp upper bound. (C) 2014 Elsevier Ltd. All rights reserved.
引用
收藏
页码:132 / 144
页数:13
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