On quasimorphisms and distortion in homeomorphism groups

Fuente: arXiv
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Autores principales: Brandenbursky, Michael, Kedra, Jarek, Marcinkowski, Michal, Shelukhin, Egor
Formato: Preprint
Publicado: 2025
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author Brandenbursky, Michael
Kedra, Jarek
Marcinkowski, Michal
Shelukhin, Egor
author_facet Brandenbursky, Michael
Kedra, Jarek
Marcinkowski, Michal
Shelukhin, Egor
contents Let $M$ be a smooth compact oriented connected manifold, and ${\rm Homeo}_0(M,μ)$ the group of homeomorphisms of $M$ supported away from $\partial M,$ which preserve a Borel probability measure $μ$ induced by a volume form on $M$, and are isotopic to the identity. In this paper, we identify those Gambaudo-Ghys and Polterovich quasimorphisms $Ψ\colon {\rm Diff}_0(M,μ)\to R$ which extend $C^0$-continuously to ${\rm Homeo}_0(M,μ)$ as quasimorphisms, and to ${\rm Homeo}_0(M)$ as group cochains whose differentials are semi-bounded cocycles. We present several applications of this result which include unboundedness of certain bi-invariant metric on the commutator subgroup of ${\rm Homeo}_0(M,μ)$, and conditions under which a homeomorphism in ${\rm Homeo}_0(M)$ is undistorted.
format Preprint
id arxiv_https___arxiv_org_abs_2512_15375
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On quasimorphisms and distortion in homeomorphism groups
Brandenbursky, Michael
Kedra, Jarek
Marcinkowski, Michal
Shelukhin, Egor
Geometric Topology
Dynamical Systems
Group Theory
Let $M$ be a smooth compact oriented connected manifold, and ${\rm Homeo}_0(M,μ)$ the group of homeomorphisms of $M$ supported away from $\partial M,$ which preserve a Borel probability measure $μ$ induced by a volume form on $M$, and are isotopic to the identity. In this paper, we identify those Gambaudo-Ghys and Polterovich quasimorphisms $Ψ\colon {\rm Diff}_0(M,μ)\to R$ which extend $C^0$-continuously to ${\rm Homeo}_0(M,μ)$ as quasimorphisms, and to ${\rm Homeo}_0(M)$ as group cochains whose differentials are semi-bounded cocycles. We present several applications of this result which include unboundedness of certain bi-invariant metric on the commutator subgroup of ${\rm Homeo}_0(M,μ)$, and conditions under which a homeomorphism in ${\rm Homeo}_0(M)$ is undistorted.
title On quasimorphisms and distortion in homeomorphism groups
topic Geometric Topology
Dynamical Systems
Group Theory
url https://arxiv.org/abs/2512.15375