Search Results
Search type | Search syntax |
---|---|
Tags | [tag] |
Exact | "words here" |
Author |
user:1234 user:me (yours) |
Score |
score:3 (3+) score:0 (none) |
Answers |
answers:3 (3+) answers:0 (none) isaccepted:yes hasaccepted:no inquestion:1234 |
Views | views:250 |
Code | code:"if (foo != bar)" |
Sections |
title:apples body:"apples oranges" |
URL | url:"*.example.com" |
Saves | in:saves |
Status |
closed:yes duplicate:no migrated:no wiki:no |
Types |
is:question is:answer |
Exclude |
-[tag] -apples |
For more details on advanced search visit our help page |
Euclidean, hyperbolic, discrete, convex, coarse geometry, metric spaces, comparisons in Riemannian geometry, symmetric spaces.
10
votes
Accepted
A possible characterization of sphere or projective space
The article by X. Liu and Sh. Deng "The antipodal sets of compact symmetric spaces" gives many examples, e.g. $\mathrm{SU}(2n)$, $\mathrm{Spin}(5)$, $\mathrm{Spin}(7)$,.... All those spaces have uniqu …
10
votes
Derivative of distance function to a closed, rectifiable set
The distance $f: x \mapsto \mathsf{dist}(x,\Gamma)$ to a closed set $\Gamma$ in $\mathbb{R}^n$ is differentiable in $x \notin \Gamma$ iff the nearest point projection is unique; denote this by $x_\Gam …
5
votes
Functions that map open balls to open balls of different radius?
For $n\ge 2$ every balloon map is a composition of a scaling, a translation and a rotation/reflection.
The following proof is incomplete as it relies on the fact that the boundary of a ball is mappe …
5
votes
Accepted
Hausdorff distance is a lower (or upper bound) for what probability metric?
A general note is that the answer depends heavily on the properties of $\mu$.
First a note that in general $d_H(A,B) \not \le C \cdot W_p(\mu|_A,\mu|_B)$ for $p\in[1,\infty)$ and some $C>0$. Though …
3
votes
Is it possible to continuously select a probability distribution over fixed points in Brouwe...
There can be no such function even in the category of smooth functions.
Here an example for functions $f:[0,1]\to [0,1]$ with $f(0)=\epsilon$ and $f(1)=1-\epsilon$:
(1) Let $\operatorname{id}:x\ma …
2
votes
Accepted
Broken geodesic in Finsler polyhedral space
I don't follow quite the argument in the reference but maybe the following helps:
On the one hand assuming strict convexity of the inner metric there can be at most one geodesic (see (1) below). On …