English

Signature of surface bundles and bounded cohomology

Geometric Topology 2020-11-12 v1

Abstract

Extending a result of Morita, we show that all tautological classes of the moduli space of genus g curves are bounded. As an application, we obtain that for a surface bundle EBE\to B over a closed surface, the Eulder characteristic χ(E)\chi(E) and the signature σ(E)\sigma(E) are related by 3σ(E)χ(E)\vert 3 \sigma(E)\vert \leq \vert \chi(E)\vert.

Keywords

Cite

@article{arxiv.2011.05792,
  title  = {Signature of surface bundles and bounded cohomology},
  author = {Ursula Hamenstädt},
  journal= {arXiv preprint arXiv:2011.05792},
  year   = {2020}
}

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26 pages