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تسجيل مستخدم جديدMeasurable circle squaring
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Laczkovich proved that if bounded subsets $A$ and $B$ of $R^k$ have the same non-zero Lebesgue measure and the box dimension of the boundary of each set is less than $k$, then there is a partition of $A$ into finitely many parts that can be translated to form a partition of $B$. Here we show that it can be additionally required that each part is both Baire and Lebesgue measurable. As special cases, this gives measurable and translation-on
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We give a completely constructive solution to Tarskis circle squaring problem. More generally, we prove a Borel version of an equidecomposition theorem due to Laczkovich. If $k geq 1$ and $A, B subseteq mathbb{R}^k$ are bounded Borel sets with the sa
me positive Lebesgue measure whose boundaries have upper Minkowski dimension less than $k$, then $A$ and $B$ are equidecomposable by translations using Borel pieces. This answers a question of Wagon. Our proof uses ideas from the study of flows in graphs, and a recent result of Gao, Jackson, Krohne, and Seward on special types of witnesses to the hyperfiniteness of free Borel actions of $mathbb{Z}^d$.
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For an $r$-tuple $(gamma_1,ldots,gamma_r)$ of special orthogonal $dtimes d$ matrices, we say the Euclidean $(d-1)$-dimensional sphere $S^{d-1}$ is $(gamma_1,ldots,gamma_r)$-divisible if there is a subset $Asubseteq S^{d-1}$ such that its translations
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