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5 votes
1 answer
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Criterion for Kuratowski Limit Inferior

Let $(X,d_X)$ be a compact metric space and let $\{K_n\}_{n=1}^{\infty}$ be a collection of non-empty compact subsets. Let $K\subseteq X$ be compact. Then, if for every $x_n \in K_n$ we have $$ d_X(...
5 votes
0 answers
296 views

For which classes of metric spaces can we prove that quasi-isometry is an equivalence relation in ZF?

Given two metric spaces $(M_1, d_1)$ and $(M_2, d_2)$, a map $\phi \colon (M_1, d_1) \to (M_2, d_2)$ is a large-scale Lipschitz essentially surjective map if there exist constants $A \geq 1, B \geq 0$,...
1 vote
3 answers
688 views

How to show the cardinality of nonisometric compact metric spaces is the continuum

It is asserted in A Course in Metric Geometry by Burago, Burago, Ivanov that there can be no more than continuum of mutually nonisometric compact spaces How is this proven? Its clear that there ...