Hölder curves with exotic tangent spaces

Fuente: arXiv
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Main Authors: Shaw, Eve, Vellis, Vyron
Format: Preprint
Published: 2024
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author Shaw, Eve
Vellis, Vyron
author_facet Shaw, Eve
Vellis, Vyron
contents An important implication of Rademacher's Differentiation Theorem is that every Lipschitz curve $Γ$ infinitesimally looks like a line at almost all of its points in the sense that at $\mathcal{H}^1$-almost every point of $Γ$, the only tangent to $Γ$ is a straight line through the origin. In this article, we show that, in contrast, the infinitesimal structure of Hölder curves can be much more extreme. First we show that for every $s>1$ there exists a $(1/s)$-Hölder curve $Γ_s$ in a Euclidean space with $\mathcal{H}^s(Γ_s)>0$ such that $\mathcal{H}^s$-almost every point of $Γ_s$ admits infinitely many topologically distinct tangents. Second, we study the tangents of self-similar connected sets (which are canonical examples of Hölder curves) and prove that the curves $Γ_s$ have the additional property that $\mathcal{H}^s$-almost every point of $Γ_s$ admits infinitely many homeomorphically distinct tangents to $Γ_s$ which are not admitted as (not even bi-Lipschitz to) tangents to any self-similar set at typical points.
format Preprint
id arxiv_https___arxiv_org_abs_2409_13662
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Hölder curves with exotic tangent spaces
Shaw, Eve
Vellis, Vyron
Metric Geometry
Dynamical Systems
28A80 (Primary) 26A16, 28A75, 53A04
An important implication of Rademacher's Differentiation Theorem is that every Lipschitz curve $Γ$ infinitesimally looks like a line at almost all of its points in the sense that at $\mathcal{H}^1$-almost every point of $Γ$, the only tangent to $Γ$ is a straight line through the origin. In this article, we show that, in contrast, the infinitesimal structure of Hölder curves can be much more extreme. First we show that for every $s>1$ there exists a $(1/s)$-Hölder curve $Γ_s$ in a Euclidean space with $\mathcal{H}^s(Γ_s)>0$ such that $\mathcal{H}^s$-almost every point of $Γ_s$ admits infinitely many topologically distinct tangents. Second, we study the tangents of self-similar connected sets (which are canonical examples of Hölder curves) and prove that the curves $Γ_s$ have the additional property that $\mathcal{H}^s$-almost every point of $Γ_s$ admits infinitely many homeomorphically distinct tangents to $Γ_s$ which are not admitted as (not even bi-Lipschitz to) tangents to any self-similar set at typical points.
title Hölder curves with exotic tangent spaces
topic Metric Geometry
Dynamical Systems
28A80 (Primary) 26A16, 28A75, 53A04
url https://arxiv.org/abs/2409.13662