Quasi-homomorphisms on mapping class groups

2007/02/09 by Mladen Bestvina, Koji Fujiwara, Bestvina, Mladen +1 · 1 citation
Mathematics · #FOS: Mathematics #Geometric Topology (math.GT) #Geometric and Algebraic Topology #Group Theory (math.GR) #math.GR #math.GT

paper · pdf · doi:10.48550/arxiv.math/0702273

arxiv created 2007/02/09 · openalex publication_date 2007/02/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We refine the construction of quasi-homomorphisms on mapping class groups. It is useful to know that there are unbounded quasi-homomorphisms which are bounded when restricted to particular subgroups since then one deduces that the mapping class group is not boundedly generated by these subgroups. In this note we enlarge the class of such subgroups. The generalization is motivated by considerations in first order theory of free groups.

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