New York Journal of Mathematics
Volume 23 (2017) 833-858

  

Itai Benjamini, Hugo Duminil-Copin, Gady Kozma, and Ariel Yadin

Minimal growth harmonic functions on lamplighter groups

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Published: July 16, 2017
Keywords: Harmonic functions, random walk, lamplighter, wreath product, entropy, Kaimanovich-Vershik
Subject: 60J45, 30F15, 05C63

Abstract
We study the minimal possible growth of harmonic functions on lamplighters. We find that (Z/2)≀ Z has no sublinear harmonic functions, (Z/2)≀ Z2 has no sublogarithmic harmonic functions, and neither has the repeated wreath product (...b(Z/2≀Z2)≀Z2)≀...b≀Z2. These results have implications on attempts to quantify the Derriennic-Kaimanovich-Vershik theorem

Acknowledgements

HDC was funded by the IDEX chair of Paris-Saclay as well as the Swiss NSF and the NCCR SwissMap. GK is partially supported by the Israel Science Foundation (grant no. 1369/15) and by the Jesselson Foundation. AY is partially supported by the Israel Science Foundation (grant no. 1346/15).


Author information

Itai Benjamini:
The Weizmann Institute of Science, Rehovot, Israel
itai.benjamini@weizmann.ac.il

Hugo Duminil-Copin:
Institut des Hautes Études Scientifiques, Bures-Sur-Yvette, France and Université de Genève, Genève, Switzerland
duminil@ihes.fr

Gady Kozma:
The Weizmann Institute of Science, Rehovot, Israel
gady.kozma@weizmann.ac.il

Ariel Yadin:
Ben-Gurion University of the Negev, Beer Sheva, Israel
yadina@bgu.ac.il