On growth of cocycles of isometric representations on $L^p$-spaces

Fuente: arXiv
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Main Authors: Neumann, Antonio López, Paucar, Juan
Format: Preprint
Published: 2025
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author Neumann, Antonio López
Paucar, Juan
author_facet Neumann, Antonio López
Paucar, Juan
contents We study different notions of asymptotic growth for 1-cocycles of isometric representations on Banach spaces. One can see this as a way of quantifying the absence of fixed point properties on such spaces. Inspired by the work of Lafforgue, we show the following dichotomy: for a compactly generated group $G$, either all 1-cocycles of $G$ taking values in $L^p$-spaces are bounded (this is Property $FL^p$) or there exists a 1-cocycle of $G$ taking values in an $L^p$-space with relatively fast growth. We also obtain upper and lower bounds on the average growth of harmonic 1-cocycles with values in Banach spaces with convexity properties. As a consequence, we obtain bounds on the average growth of all 1-cocycles with values in $L^p$-spaces for groups with property $(T)$. Lastly, we show that for a compactly generated group $G$, the existence of a 1-cocycle with compression larger than $\sqrt{n}$ implies the Liouville property for a large family of probability measures on $G$.
format Preprint
id arxiv_https___arxiv_org_abs_2501_12808
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On growth of cocycles of isometric representations on $L^p$-spaces
Neumann, Antonio López
Paucar, Juan
Group Theory
Functional Analysis
20J06, 22D05, 22D55, 46B08
We study different notions of asymptotic growth for 1-cocycles of isometric representations on Banach spaces. One can see this as a way of quantifying the absence of fixed point properties on such spaces. Inspired by the work of Lafforgue, we show the following dichotomy: for a compactly generated group $G$, either all 1-cocycles of $G$ taking values in $L^p$-spaces are bounded (this is Property $FL^p$) or there exists a 1-cocycle of $G$ taking values in an $L^p$-space with relatively fast growth. We also obtain upper and lower bounds on the average growth of harmonic 1-cocycles with values in Banach spaces with convexity properties. As a consequence, we obtain bounds on the average growth of all 1-cocycles with values in $L^p$-spaces for groups with property $(T)$. Lastly, we show that for a compactly generated group $G$, the existence of a 1-cocycle with compression larger than $\sqrt{n}$ implies the Liouville property for a large family of probability measures on $G$.
title On growth of cocycles of isometric representations on $L^p$-spaces
topic Group Theory
Functional Analysis
20J06, 22D05, 22D55, 46B08
url https://arxiv.org/abs/2501.12808