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JOURNALS // Zhurnal Matematicheskoi Fiziki, Analiza, Geometrii [Journal of Mathematical Physics, Analysis, Geometry] // Archive

Zh. Mat. Fiz. Anal. Geom., 2020 Volume 16, Number 1, Pages 46–54 (Mi jmag746)

A nonsingular action of the full symmetric group admits an equivalent invariant measure

Nikolay Nessonov

B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Nauky Ave., Kharkiv, 61103, Ukraine

Abstract: Let $\overline{\mathfrak{S}}_\infty$ denote the set of all bijections of natural numbers. Consider an action of $\overline{\mathfrak{S}}_\infty$ on a measure space $\left( X,\mathfrak{M},\mu \right)$, where $\mu$ is an $\overline{\mathfrak{S}}_\infty$-quasi-invariant measure. We prove that there exists an $\overline{\mathfrak{S}}_\infty$-invariant measure equivalent to $\mu$.

Key words and phrases: full symmetric group, nonsingular automorphism, Koopman representation, invariant measure.

MSC: 37A40, 22A25, 22F10.

Received: 11.11.2018
Revised: 09.10.2019

Language: English

DOI: 10.15407/mag16.01.046



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