{ "id": "2106.06177", "version": "v1", "published": "2021-06-11T05:42:40.000Z", "updated": "2021-06-11T05:42:40.000Z", "title": "Existence of quasiconformal maps with maximal stretching on any given countable set", "authors": [ "Tyler Bongers", "James T. Gill" ], "comment": "10 pages", "categories": [ "math.CA", "math.CV" ], "abstract": "Quasiconformal maps are homeomorphisms with useful local distortion inequalities; infinitesimally, they map balls to ellipsoids with bounded eccentricity. This leads to a number of useful regularity properties, including quantitative H\\\"older continuity estimates; on the other hand, one can use the radial stretches to characterize the extremizers for H\\\"older continuity. In this work, given any bounded countable set in $\\mathbb{R}^d$, we will construct an example of a $K$-quasiconformal map which exhibits the maximum stretching at each point of the set. This will provide an example of a quasiconformal map that exhibits the worst-case regularity on a surprisingly large set, and generalizes constructions from the planar setting into $\\mathbb{R}^d$.", "revisions": [ { "version": "v1", "updated": "2021-06-11T05:42:40.000Z" } ], "analyses": { "subjects": [ "30C65" ], "keywords": [ "quasiconformal map", "countable set", "maximal stretching", "useful local distortion inequalities", "surprisingly large set" ], "note": { "typesetting": "TeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable" } } }