中文

系数在一致凸 Banach 空间中的有界上同调

群论 2015-02-16 v2 几何拓扑

摘要

我们证明:对于无平凡有限正规子群的 acylindrically hyperbolic 群 Γ\Gamma,以及 Γ\Gamma 在(非零)一致凸 Banach 空间中的任意酉表示 ρ\rho,向量空间 Hb2(Γ;ρ)H^2_b(\Gamma;\rho) 是无限维的。该结果此前已知适用于 p(Γ)\ell^p(\Gamma) 上的正则表示(1<p<1<p<\infty),但论证方法不同。然而,即使在非阿贝尔自由群的情形下,我们的结果在如此广泛的表示类中也是新的;此外,acylindrically hyperbolic 群的情形可作为推论得出。

关键词

引用

@article{arxiv.1306.1542,
  title  = {Bounded cohomology with coefficients in uniformly convex Banach spaces},
  author = {Mladen Bestvina and Ken Bromberg and Koji Fujiwara},
  journal= {arXiv preprint arXiv:1306.1542},
  year   = {2015}
}

备注

The title has been changed. The old title was "Bounded cohomology via quasi-trees". We prove a theorem for free groups (Theorem 1.1) using actions on trees, then deal with acylindrically hyperbolic groups using a work by Hull-Osin (Corollary 1.2). In the old version we had a direct proof using quasi-trees. We move the discussion on strongly contracting geodesics to a separate paper ([3])