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arXiv · 2003.06854

Haar-positive closed subsets of Haar-positive analytic sets

Márton Elekes·Márk Poór·Zoltán Vidnyánszky
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Abstract

We show that every non-Haar-null analytic subset of $\mathbb{Z}^ω$ contains a non-Haar-null closed subset. Moreover, we also prove that the codes of Haar-null analytic subsets, and, consequently, closed Haar-null sets in the Effros Borel space of $\mathbb{Z}^ω$ form a $\mathbfΔ^1_2$ set.

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Márton Elekes, Márk Poór, Zoltán Vidnyánszky. 2020-03-15. Haar-positive closed subsets of Haar-positive analytic sets. https://arxiv.org/abs/2003.06854

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