Closed formulas for the numbers of small independent sets and matchings and an extremal problem for trees

被引:15
作者
Delorme, C
Favaron, O
Rautenbach, D
机构
[1] Univ Bonn, Forsch Inst Diskrete Math, D-53113 Bonn, Germany
[2] Univ Paris 11, Rech Informat Lab, F-91405 Orsay, France
关键词
independent set; matching; degree sequence; tree; Kruskal's algorithm;
D O I
10.1016/S0166-218X(03)00328-7
中图分类号
O29 [应用数学];
学科分类号
070104 ;
摘要
We derive closed formulas for the numbers of independent sets of size at most 4 and matchings of size at most 3 in graphs without small cycles that depend only on the degree sequence and the products of the degrees of adjacent vertices. As a related problem we describe an algorithm that determines a tree of given degree sequence that maximizes the sum of the products of the degrees of adjacent vertices. (C) 2003 Elsevier B.V. All rights reserved.
引用
收藏
页码:503 / 512
页数:10
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