arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1703.04431math.AGmath.RTmath.SG
收藏

Character品种的奇妙紧致化

Wonderful Compactification of Character Varieties

Indranil Biswas, Sean Lawton, Daniel Ramras

摘要:

利用定义在任意特征的代数闭域k上的半单伴随仿射代数群G的奇妙紧化,构造了任意有限生成群F的G-特征簇的自然紧化Y.当F是一个自由群时,我们证明了这个紧化总是关于étale基本群单连通的,并且当k=C时,它也是拓扑单连通的.对于其它群F,我们描述了模空间的紧化为单连通的条件,并给出了满足这些条件时的例子,包括闭曲面群和当G=PGL(n,C)时的自由阿尔贝群.另外,当F是自由群时,我们根据先前研究的模空间确定了Y的边界因子,并构造了由G的李代数的二重的Belavin-Drinfeld分裂产生的Y上的Poisson结构族及其边界因子.在附录中,作者山姆埃文斯和Arlo凯恩,我们解释了如何把一个泊松结构的商的泊松代数簇的行动约化泊松代数群。

英文摘要:

Using the wonderful compactification of a semisimple adjoint affine algebraic group G defined over an algebraically closed field k of arbitrary characteristic, we construct a natural compactification Y of the G-character variety of any finitely generated group F. When F is a free group, we show that this compactification is always simply connected with respect to the étale fundamental group, and when k=C it is also topologically simply connected. For other groups F, we describe conditions for the compactification of the moduli space to be simply connected and give examples when these conditions are satisfied, including closed surface groups and free abelian groups when G=PGL(n,C). Additionally, when F is a free group we identify the boundary divisors of Y in terms of previously studied moduli spaces, and we construct a family of Poisson structures on Y and its boundary divisors arising from Belavin-Drinfeld splittings of the double of the Lie algebra of G. In the appendix, authored by Sam Evens and Arlo Caine, we explain how to put a Poisson structure on a quotient of a Poisson algebraic variety by the action of a reductive Poisson algebraic group.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑