Lowener Theory on Analytic Universal Covering Maps

Fuente: arXiv
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Main Author: Yanagihara, Hiroshi
Format: Preprint
Published: 2019
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author Yanagihara, Hiroshi
author_facet Yanagihara, Hiroshi
contents We study Loewner chains in $\mathcal{H}_0(\mathbb{D})$ without assuming univalence of each element. We prove a decomposition: every chain admits a factorization $f_t=F\circ g_t$, where $F$ is analytic on $\mathbb{D}(0,r)$ with $r=\lim_{t \nearrow \sup I} f_t'(0)$, and $\{g_t\}$ is a classical Loewner chain of univalent functions. Under a mild regularity assumption on $t \mapsto f_t'(0)$, we derive a partial differential equation that generalizes the Loewner--Kufarev equation. We then develop a Loewner theory for chains of universal covering maps. We characterize such chains in terms of domain families $\{Ω_t\}$: continuity and monotonicity of $\{f_t\}$ are equivalent to kernel continuity and monotonicity of $\{Ω_t\}$. We further show that the connectivity $C(Ω_t)=\#(\hat{\mathbb{C}}\setminus Ω_t)$ is a left-continuous nondecreasing function of $t$. Building on these results, we formulate a Loewner theory on Fuchsian groups and obtain evolution equations for deck transformations. As an application, we study hyperbolic metrics and establish a formula for the logarithmic derivative of the hyperbolic density along the chain. Our results provide a unified framework linking classical Loewner theory, covering maps, and the geometry of hyperbolic domains.
format Preprint
id arxiv_https___arxiv_org_abs_1907_11987
institution arXiv
publishDate 2019
record_format arxiv
spellingShingle Lowener Theory on Analytic Universal Covering Maps
Yanagihara, Hiroshi
Complex Variables
30C35, 30F35 (Primary) 30C45(Secondary)
We study Loewner chains in $\mathcal{H}_0(\mathbb{D})$ without assuming univalence of each element. We prove a decomposition: every chain admits a factorization $f_t=F\circ g_t$, where $F$ is analytic on $\mathbb{D}(0,r)$ with $r=\lim_{t \nearrow \sup I} f_t'(0)$, and $\{g_t\}$ is a classical Loewner chain of univalent functions. Under a mild regularity assumption on $t \mapsto f_t'(0)$, we derive a partial differential equation that generalizes the Loewner--Kufarev equation. We then develop a Loewner theory for chains of universal covering maps. We characterize such chains in terms of domain families $\{Ω_t\}$: continuity and monotonicity of $\{f_t\}$ are equivalent to kernel continuity and monotonicity of $\{Ω_t\}$. We further show that the connectivity $C(Ω_t)=\#(\hat{\mathbb{C}}\setminus Ω_t)$ is a left-continuous nondecreasing function of $t$. Building on these results, we formulate a Loewner theory on Fuchsian groups and obtain evolution equations for deck transformations. As an application, we study hyperbolic metrics and establish a formula for the logarithmic derivative of the hyperbolic density along the chain. Our results provide a unified framework linking classical Loewner theory, covering maps, and the geometry of hyperbolic domains.
title Lowener Theory on Analytic Universal Covering Maps
topic Complex Variables
30C35, 30F35 (Primary) 30C45(Secondary)
url https://arxiv.org/abs/1907.11987