Mobile disks in hyperbolic space and minimization of conformal capacity

Our focus is to study constellations of disjoint disks in the hyperbolic space, i.e., the unit disk equipped with the hyperbolic metric. Each constellation corresponds to a set E which is the union of m > 2 disks with hyperbolic radii rj > 0, j = 1, . . ., m. The centers of the disks are not f...

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Bibliographic Details
Published in:ETNA - Electronic Transactions on Numerical Analysis
Main Authors: Hakula, Harri, Nasser, Mohamed M. S., Vuorinen, Matti
Format: Article in Journal/Newspaper
Language:English
Published: Kent State University 2024
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Online Access:https://hdl.handle.net/10057/27708
https://doi.org/10.1553/etna_vol60s1
Description
Summary:Our focus is to study constellations of disjoint disks in the hyperbolic space, i.e., the unit disk equipped with the hyperbolic metric. Each constellation corresponds to a set E which is the union of m > 2 disks with hyperbolic radii rj > 0, j = 1, . . ., m. The centers of the disks are not fixed, and hence individual disks of the constellation are allowed to move under the constraints that they do not overlap and their hyperbolic radii remain invariant. Our main objective is to find computational lower bounds for the conformal capacity of a given constellation. The capacity depends on the centers and radii in a very complicated way even in the simplest cases when m = 3 or m = 4. In the absence of analytic methods, our work is based on numerical simulations using two different numerical methods, the boundary integral equation method and the hp-FEM method, respectively. Our simulations combine capacity computation with minimization methods and produce extremal cases where the disks of the constellation are grouped next to each other. This resembles the behavior of animal colonies minimizing heat flow in arctic areas. © 2024 Kent State University. All rights reserved.