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arXiv · 1601.02958

Measurable equidecompositions for group actions with an expansion property

Łukasz Grabowski·András Máthé·Oleg Pikhurko
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Abstract

Given an action of a group $\Gamma$ on a measure space $\Omega$, we provide a sufficient criterion under which two sets $A, B\subseteq \Omega$ are measurably equidecomposable, i.e., $A$ can be partitioned into finitely many measurable pieces which can be rearranged using the elements of $\Gamma$ to form a partition of $B$. In particular, we prove that every bounded measurable subset of $R^n$, $n\ge 3$, with non-empty interior is measurably equidecomposable to a ball via isometries. The analogous result also holds for some other spaces, such as the sphere or the hyperbolic space of dimension $n\ge 2$.

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Łukasz Grabowski, András Máthé, Oleg Pikhurko. 2016-01-12. Measurable equidecompositions for group actions with an expansion property. https://doi.org/10.4171/jems%2F1189

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