Timeline for Uniform Embedding into Euclidean Space
Current License: CC BY-SA 3.0
6 events
when toggle format | what | by | license | comment | |
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Jul 9, 2012 at 14:56 | comment | added | Sergey Melikhov | Hannes, your question is discussed at length in Isbell's book "Uniform spaces", and in some of his preceding papers. He gives some necessary conditions which make it clear that the question is not likely to have a simple answer. | |
Jul 7, 2012 at 18:48 | comment | added | Emil Jeřábek | Note that even if you drop the assumption that $Y$ be closed, this set cannot get too wild: the other assumptions imply $Y$ is locally compact, which means it can be written as a difference of two closed sets. | |
Jul 6, 2012 at 14:44 | comment | added | Hannes Thiel | Emil, I agree. Every closed subset of $\mathbb{R}^n$ is complete, and uniform equivalence of metric spaces preserves completeness. Thus, when asking for spaces that are uniformly equivalent to closed subsets of Euclidean space, one has to add completeness to the list of neccessary conditions. But it is maybe more natural to drop the assumption that $Y\subset\mathbb{R}^n$ be closed. | |
Jul 5, 2012 at 16:17 | comment | added | Emil Jeřábek | Why do you require $Y$ to be closed? $X=(0,1)\subseteq\mathbb R$ meets your conditions, but AFAICS it is not uniformly equivalent to a closed subset $Y\subseteq\mathbb R^n$ ($X$ is bounded, hence so is $Y$, hence $Y$ is compact, hence $X$ is, but it actually isn’t). | |
Jul 5, 2012 at 16:16 | answer | added | Anton Petrunin | timeline score: 2 | |
Jul 5, 2012 at 15:33 | history | asked | Hannes Thiel | CC BY-SA 3.0 |