Skip to main content

All Questions

Filter by
Sorted by
Tagged with
18 votes
1 answer
4k views

reference for "X compact <=> C_b(X) separable" (X metric space)

I know (and am able to prove via Stone-Čech compactification) that the following is correct: Theorem: A metric space is compact if and only if its space of bounded, continuous, real-valued ...
Wolfgang Loehr's user avatar
16 votes
5 answers
903 views

Which metric spaces have this superposition property?

Let $A \subset X$ and $B \subset X$ be two isometric subsets of a metric space $X$. So there is an isometry $f: A \to B$. Say that a metric space $X$ has the superposition property (my terminology) ...
Joseph O'Rourke's user avatar
6 votes
1 answer
333 views

Trasportation metric (AKA Earth-Mover's, Wasserstein, etc.) as "natural" / "induced"?

Context: Given a discrete finite metric space $X$ (in my case X={0,1}$^n$ with the Hamming/L$_1$ distance), I need to define the natural or canonical metric on the set of all probability distributions ...
Matteo Mainetti's user avatar
9 votes
3 answers
836 views

What makes a distance?

In the answers to my previous question, I learned that there are different concepts of distance, that is of distance-like functions with the usual metric being only the most popular and important one. ...
Hans-Peter Stricker's user avatar
4 votes
1 answer
1k views

Length spaces with continuous length functional: is this set Gromov-Hausdorff closed?

As far as I can tell, a major motivation for the study of length spaces is that they arise as Gromov-Hausdorff limits of Riemannian manifolds. Specifically, A complete connected Riemannian manifold ...
macbeth's user avatar
  • 3,212
0 votes
1 answer
526 views

How the distance between sets is called?

Hello, I've recently write down some measure for sets and now I wonder how it is called or where it is described? The measure itself is the following: Let $A$ & $B$ -- two sets of values from a ...
Dair T'arg's user avatar
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 ...
Otis Chodosh's user avatar
  • 7,197
15 votes
3 answers
7k views

A metric for Grassmannians

I'm reading an article by Ricardo Mañé, "The Hausdorff dimension of horseshoes of diffeomorphisms of surfaces" (https://doi.org/10.1007/BF02585431). I'm having a technical problem. Sorry for ...
user avatar
10 votes
1 answer
560 views

Are packing-homogeneous spaces homogeneous?

Given a metric space (M,d) define the packing function P(x,R,r) to be the maximum number of non-intersecting balls of radius r with centers in the ball B(x,R). Let’s call M packing-homogeneous if the ...
Yevgeny Liokumovich's user avatar

1 2 3
4