RUS  ENG
Full version
JOURNALS // Sibirskii Matematicheskii Zhurnal // Archive

Sibirsk. Mat. Zh., 2024 Volume 65, Number 5, Pages 785–794 (Mi smj7891)

The ptolemaic characteristic of tetrads and quasiregular mappings

V. V. Aseev

Sobolev Institute of Mathematics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk

Abstract: We consider the Ptolemaic characteristic of quadruples of disjoint nonempty compact subsets (generalized tetrads). The main theorem of this article asserts that an arbitrary multivalued mapping $F$ from ${\Bbb R}^n$ onto itself such that the images of distinct points are disjoint and each of them contains at most two distinct points is the inverse of a $K$-quasimeromorphic mapping if and only if $F$ admits a controllable upper bound for the distortion of the Ptolemaic characteristic of tetrads.

Keywords: mapping with bounded distortion, quasiregular mapping, quasimeromorphic mapping, quasimöbius mapping, multivalued mapping, Ptolemaic characteristic of tetrads.

UDC: 517.54

MSC: 35R30

Received: 06.02.2024
Revised: 06.02.2024
Accepted: 20.08.2024

DOI: 10.33048/smzh.2024.65.502


 English version:
Siberian Mathematical Journal, 2024, 65:5, 995–1002


© Steklov Math. Inst. of RAS, 2026