A1 Refereed original research article in a scientific journal
Conformal capacity of hedgehogs
Authors: Betsakos Dimitrios, Solynin Alexander, Vuorinen Matti
Publisher: AMER MATHEMATICAL SOC
Publication year: 2023
Journal: Conformal Geometry and Dynamics
Journal name in source: CONFORMAL GEOMETRY AND DYNAMICS
Journal acronym: CONFORM GEOM DYN
Volume: 27
Issue: 5
First page : 55
Last page: 97
Number of pages: 43
ISSN: 1088-4173
DOI: https://doi.org/10.1090/ecgd/381
Web address : https://doi.org/10.1090/ecgd/381
Self-archived copy’s web address: https://arxiv.org/abs/2205.08107v2
Preprint address: https://arxiv.org/abs/2205.08107v1
We discuss problems concerning the conformal condenser capacity of “hedgehogs”, which are compact sets E in the unit disk D = {z: |z| < 1} consisting of a central body E0 that is typically a smaller disk Dr = {z: |z| ≤ r}, 0 < r < 1, and several spikes Ek that are compact sets lying on radial intervals I(αk) = {teiαk: 0 ≤ t < 1}. The main questions we are concerned with are the following: (1) How does the conformal capacity cap(E) of (E = ∪nk=0Ek) behave when the spikes Ek, k = 1,…, n, move along the intervals I(αk) toward the central body if their hyperbolic lengths are preserved during the motion? (2) How does the capacity cap(E) depend on the distribution of angles between the spikes Ek? We prove several results related to these questions and discuss methods of applying symmetrization type transformations to study the capacity of hedgehogs. Several open problems, including problems on the capacity of hedgehogs in the three-dimensional hyperbolic space, will also be suggested.