Hostname: page-component-77f85d65b8-zzw9c Total loading time: 0 Render date: 2026-03-30T01:05:36.108Z Has data issue: false hasContentIssue false

Bisections of Graphs Without Short Cycles

Published online by Cambridge University Press:  28 September 2017

GENGHUA FAN
Affiliation:
Center for Discrete Mathematics, Fuzhou University, Fujian 350116, China (e-mail: fan@fzu.edu.cn)
JIANFENG HOU*
Affiliation:
Center for Discrete Mathematics, Fuzhou University, Fujian 350116, China (e-mail: fan@fzu.edu.cn)
XINGXING YU
Affiliation:
School of Mathematics, Georgia Institute of Technology, Atlanta, GA 30332-0160, USA (e-mail: yu@math.gatech.edu)

Abstract

Bollobás and Scott (Random Struct. Alg.21 (2002) 414–430) asked for conditions that guarantee a bisection of a graph with m edges in which each class has at most (1/4+o(1))m edges. We demonstrate that cycles of length 4 play an important role for this question. Let G be a graph with m edges, minimum degree δ, and containing no cycle of length 4. We show that if (i) G is 2-connected, or (ii) δ ⩾ 3, or (iii) δ ⩾ 2 and the girth of G is at least 5, then G admits a bisection in which each class has at most (1/4+o(1))m edges. We show that each of these conditions are best possible. On the other hand, a construction by Alon, Bollobás, Krivelevich and Sudakov shows that for infinitely many m there exists a graph with m edges and girth at least 5 for which any bisection has at least (1/4−o(1))m edges in one of the two classes.

Information

Type
Paper
Copyright
Copyright © Cambridge University Press 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable