Enumeration of subgroups in the fundamental groups of orientable circle bundles over surfaces
作者:
Valery Liskovets,
Alexander Mednykh,
期刊:
Communications in Algebra
(Taylor Available online 2000)
卷期:
Volume 28,
issue 4
页码: 1717-1738
ISSN:0092-7872
年代: 2000
DOI:10.1080/00927870008826924
出版商: Gordon and Breach Science Publishers Ltd.
关键词: Seifert fibre space;S1-bundle;Euler number;3-manifold;surface group;covering;fundamental group;transitive permutational
数据来源: Taylor
摘要:
The aim of this paper is to count subgroups of a given index in the fundamental group of an orientableS1-bundle over a compact surface. The number of subgroups of indexnturns out to be independent of the orientability of the base surface 𝔣, closed or bordered, and is expressed as a linear combination of the numbers of surface subgroups of indicesm = n/ll∣n. For a closed base surface of characteristic χ the respective coefficients are equal tol–χm+2or vanish depending onl,nand the Euler number of theS1-bundle.
点击下载:
PDF (824KB)
返 回