Vietoris--Rips complexes of ellipses at larger scales

Fuente: arXiv
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Auteurs principaux: Adams, Henry, Carvajal, Julian, Rhodes, Jake, Turillo, Niccolo, Ye, Jingkai, Ying, Raymond
Format: Preprint
Publié: 2025
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author Adams, Henry
Carvajal, Julian
Rhodes, Jake
Turillo, Niccolo
Ye, Jingkai
Ying, Raymond
author_facet Adams, Henry
Carvajal, Julian
Rhodes, Jake
Turillo, Niccolo
Ye, Jingkai
Ying, Raymond
contents For $X$ a metric space and $r>0$, the Vietoris--Rips simplicial complex $\mathrm{VR}(X;r)$ has $X$ as its vertex set, and a finite subset $σ\subseteq X$ as a simplex whenever the diameter of $σ$ is less than $r$. In ``On Vietoris--Rips complexes of ellipses'', the authors studied the homotopy types of Vietoris--Rips complexes of ellipses $E_a=\{(x,y)\in \mathbb{R}^2~|~(x/a)^2+y^2=1\}$ of small eccentricity, meaning $1<a< \sqrt{2}$, at small scales $r < \frac{4\sqrt{3}a^2}{3a^2+1}$. In this paper, we further investigate the homotopy types that appear at larger scales. In particular, we identify the scale parameters $r$, as a function of the eccentricity $a$, for which the Vietoris--Rips complex $\mathrm{VR}(E_a;r)$ is homotopy equivalent to a $3$-sphere, to a wedge sum of $4$-spheres, or to a $5$-sphere.
format Preprint
id arxiv_https___arxiv_org_abs_2511_09471
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Vietoris--Rips complexes of ellipses at larger scales
Adams, Henry
Carvajal, Julian
Rhodes, Jake
Turillo, Niccolo
Ye, Jingkai
Ying, Raymond
Metric Geometry
Algebraic Topology
05E45, 55U10, 68R05
For $X$ a metric space and $r>0$, the Vietoris--Rips simplicial complex $\mathrm{VR}(X;r)$ has $X$ as its vertex set, and a finite subset $σ\subseteq X$ as a simplex whenever the diameter of $σ$ is less than $r$. In ``On Vietoris--Rips complexes of ellipses'', the authors studied the homotopy types of Vietoris--Rips complexes of ellipses $E_a=\{(x,y)\in \mathbb{R}^2~|~(x/a)^2+y^2=1\}$ of small eccentricity, meaning $1<a< \sqrt{2}$, at small scales $r < \frac{4\sqrt{3}a^2}{3a^2+1}$. In this paper, we further investigate the homotopy types that appear at larger scales. In particular, we identify the scale parameters $r$, as a function of the eccentricity $a$, for which the Vietoris--Rips complex $\mathrm{VR}(E_a;r)$ is homotopy equivalent to a $3$-sphere, to a wedge sum of $4$-spheres, or to a $5$-sphere.
title Vietoris--Rips complexes of ellipses at larger scales
topic Metric Geometry
Algebraic Topology
05E45, 55U10, 68R05
url https://arxiv.org/abs/2511.09471