Impossibility of decoding a translation invariant measure from a single set of positive Lebesgue measure

Fuente: arXiv
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Autor principal: Bulj, Aleksandar
Formato: Preprint
Publicado: 2024
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author Bulj, Aleksandar
author_facet Bulj, Aleksandar
contents Let $μ$ be a translation invariant measure on $(\mathbb{R}^d,\mathcal{B}(\mathbb{R}^d))$ and let $λ$ denote the Lebesgue measure on $\mathbb{R}^d$. If there exists an open set $U$ such that $0<μ(U)=λ(U)<\infty$, it is a simple exercise to show that $μ=λ|_{\mathcal{B}(\mathbb{R}^d)}$. Is the same conclusion true if $U$ is merely a Borel set? The main purpose of this short note is to construct a measure that provides a negative answer to this question. Incidentally, this construction provides a new example of a translation invariant measure with a rich domain and range that is not Hausdorff, a problem previously studied by Hirst.
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publishDate 2024
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spellingShingle Impossibility of decoding a translation invariant measure from a single set of positive Lebesgue measure
Bulj, Aleksandar
Classical Analysis and ODEs
Let $μ$ be a translation invariant measure on $(\mathbb{R}^d,\mathcal{B}(\mathbb{R}^d))$ and let $λ$ denote the Lebesgue measure on $\mathbb{R}^d$. If there exists an open set $U$ such that $0<μ(U)=λ(U)<\infty$, it is a simple exercise to show that $μ=λ|_{\mathcal{B}(\mathbb{R}^d)}$. Is the same conclusion true if $U$ is merely a Borel set? The main purpose of this short note is to construct a measure that provides a negative answer to this question. Incidentally, this construction provides a new example of a translation invariant measure with a rich domain and range that is not Hausdorff, a problem previously studied by Hirst.
title Impossibility of decoding a translation invariant measure from a single set of positive Lebesgue measure
topic Classical Analysis and ODEs
url https://arxiv.org/abs/2406.06065