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Questions tagged [metric-geometry]

The study of geometry of manifolds without appealing to differential calculus. It includes studies of length spaces, Alexandrov spaces, and CAT(k) spaces. The techniques are often applicable to Riemannian/Finsler geometry (where differential calculus is used) and geometric group theory. For questions about plain-old metric spaces, please use (metric-spaces) instead.

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Let $f:M\to\mathbb{R}^k$ be smooth, where $M$ is a closed manifold of dimension $n>k$. I am thinking about the continuity properties of the map $c\mapsto\mathcal{H}^{n-k}(f^{-1}(c))$. Clearly this ...
strtlmp's user avatar
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Let $X$ be a 2-dim CBB($k$) space, and $AO,BO,CO$ are all geodesics, do WE have $$\angle AOC=\angle AOB+\angle BOC\,?$$ I know that if $AC$ is geodesic, then $\angle AOB+\angle BOC=\pi$, but in ...
Leo's user avatar
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Some context and motivation for this question: A friend posed to me the following puzzle. Given eight points in the unit disc, why must there exist a pair of points with distance less than $ 1 $? The ...
Cranium Clamp's user avatar
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I'm studying Roman Vershynin's High-Dimensional Probability and am working through Corollary 0.0.4, where he constructs an epsilon-net for a polytope $P$ via averages of vertices. Here's what confused ...
Sophia 's user avatar
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A set $E \subset \mathbb{R}^d$ is called $1$-rectifiable if there exists a (countable) family of Lipschitz mappings $f_i : \mathbb{R} \rightarrow \mathbb{R}^d$ such that $$ H^1 \bigg(E \setminus \...
PNW Mathematician's user avatar
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Let $M$ be a 3-dimensional Cartan-Hadamard manifold (complete, simply connected, with nonpositive sectional curvature). Let $S \subset M$ be a $C^{1,1}$ surface enclosing a domain $E$, and let $D_0$ ...
HIH's user avatar
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Let $M$ be a 3-dimensional Cartan–Hadamard manifold (complete, simply connected, nonpositive sectional curvature), let $S \subset M$ be a $C^{1,1}$ surface enclosing a domain $E$, and let $D_0$ be the ...
HIH's user avatar
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Let $(M,g)$ be a Cartan-Hadamard manifold (simply connected, complete and with sectional curvature K≤0 ) and let $K \subset M$ be a closed convex body with $C^{1,1}$ boundary. Fix an interior point $p ...
HIH's user avatar
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2 votes
1 answer
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While studying the notion of asymptotic dimension, I got interested in the examples of classes of metric spaces with a computable asymptotic dimension. The definition of asymptotic dimension I'm used ...
IMN's user avatar
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2 votes
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I have a convex curve $\gamma$ on a two-dimensional Riemannian manifold with positive Gaussian curvature, or a Alexandrov space with curvature $\geq 0$, which is a simple closed curve, and the region ...
Leo's user avatar
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I was studying the following discussion on Mathoverflow: Continuous automorphism groups of normed vector spaces, where it is mentioned that "The isometry group of any (real) finite-dimensional ...
Tintin's user avatar
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4 votes
1 answer
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For a closed convex curve $\gamma: I \to \mathbb{R}^2$, where the region enclosed by the curve is convex, the Menger curvature is defined as follows: for three distinct points $m, p, q$ on the curve, ...
Leo's user avatar
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Theorem in question: I understood the first part, I don't understand the converse. Why can we assume that for all $v \in V_{ij}$ point $w_i$ is the nearest neighbor? Can't we say that $w_i$ or $w_j$ ...
Shrihan Pande's user avatar
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Im struggeling to do a proof of Gromov-Bishop volume comparison theorem restricted to the 2 dimensional case. I have very little experience in working with Riemannian geometry, therefor the need to ...
Kløjs's user avatar
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2 votes
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I have recently come across the following, very intuitive, statement within the book "A course in Metric Geometry" by Burago, Burago, Ivanov. It asserts that we can calculate the length of ...
devil in the details's user avatar

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