Lifting of homeomorphisms to 4-sheeted branched coverings of a disk

被引：2

作者：

Wajnryb, Bronislaw ^{[1
]}

Wisniowska-Wajnryb, Agnieszka ^{[1
]}

机构：

[1] Rzeszow Univ Technol, Dept Math, PL-35959 Rzeszow, Poland

来源：

TOPOLOGY AND ITS APPLICATIONS | 2008年 / 155卷 / 16期

关键词：

braids; branched coverings; homeomorphisms; surfaces;

D O I：

10.1016/j.topol.2008.06.002

中图分类号：

O29 [应用数学];

学科分类号：

070104 ;

摘要：

Let p : X -> D be a simple, possibly not connected, 4-sheeted branched covering of a closed 2-dimensional disk D with n branch values A(1)..... A(n). The isotopy classes of homeomorphisms of D which are fixed on the boundary of D and permute the branch values form a braid group B, Some of these homeomorphisms can be lifted to homeomorphisnis of X. They form a subgroup L(p) of finite index in B-n. For each equivalence class of coverings we find a set of generators for L(p) which contains between n and n + 4 elements, depending on the equivalence class of the covering, and the generators are powers of half-twists. (C) 2008 Elsevier B.V. All rights reserved.

引用

页码：1820 / 1839

页数：20