Integrable measure equivalence and the central extension of surface groups

Fuente: arXiv
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Main Authors: Das, Kajal, Tessera, Romain
Format: Preprint
Published: 2014
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author Das, Kajal
Tessera, Romain
author_facet Das, Kajal
Tessera, Romain
contents Let $Γ_g$ be a surface group of genus $g\geq 2$. It is known that the canonical central extension $\tildeΓ_g$ and the direct product $Γ_g\times \mathbb{Z}$ are quasi-isometric. It is also easy to see that they are measure equivalent. By contrast, in this paper, we prove that quasi-isometry and measure equivalence cannot be achieved "in a compatible way". More precisely, these two groups are not uniform (nor even integrable) measure equivalent. In particular, they cannot act continuously, properly and cocompactly by isometries on the same proper metric space, or equivalently they are not uniform lattices in a same locally compact group.
format Preprint
id arxiv_https___arxiv_org_abs_1405_2667
institution arXiv
publishDate 2014
record_format arxiv
spellingShingle Integrable measure equivalence and the central extension of surface groups
Das, Kajal
Tessera, Romain
Metric Geometry
Group Theory
Group Theory (math.GR), Metric Geometry (math.MG)
Let $Γ_g$ be a surface group of genus $g\geq 2$. It is known that the canonical central extension $\tildeΓ_g$ and the direct product $Γ_g\times \mathbb{Z}$ are quasi-isometric. It is also easy to see that they are measure equivalent. By contrast, in this paper, we prove that quasi-isometry and measure equivalence cannot be achieved "in a compatible way". More precisely, these two groups are not uniform (nor even integrable) measure equivalent. In particular, they cannot act continuously, properly and cocompactly by isometries on the same proper metric space, or equivalently they are not uniform lattices in a same locally compact group.
title Integrable measure equivalence and the central extension of surface groups
topic Metric Geometry
Group Theory
Group Theory (math.GR), Metric Geometry (math.MG)
url https://arxiv.org/abs/1405.2667