Irreducible $\Sp$-representations and subgroup distortion in the mapping class group
Irreducible $\Sp$-representations and subgroup distortion in the mapping class group
复制标题
映射类群中的不可约 $Sp$-表示和子群失真
DOI:
10.4171/cmh/233
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发表时间:
2007
期刊:
影响因子:
--
通讯作者:
Andrew Putman
中科院分区:
文献类型:
--
作者:
N. Broaddus;B. Farb;Andrew Putman
We prove that various subgroups of the mapping class group $Mod(\Sigma)$ of a surface $\Sigma$ are at least exponentially distorted. Examples include the Torelli group (answering a question of Hamenstadt), the "point-pushing" and surface braid subgroups, and the Lagrangian subgroup. Our techniques include a method to compute lower bounds on distortion via representation theory and an extension of Johnson theory to arbitrary subgroups of $H_1(\Sigma;\mathbb{Z})$.