Search

In this paper, we provide partial solutions to a problem raised by Vaisala on local properties of free quasiconformal mappings. In particular, we show that a locally free quasiconformal mapping is a globally free quasiconformal mapping under the condition of locally relative quasisymmetry.

In this paper, we introduce a class of mappings related to the distance ratio metric and study its connection to the freely quasiconformal mapping in Banach spaces. Moreover, we investigate the invariance of Gromov hyperbolic, natural and uniform domains under this class of mappings.

The main purpose of this paper is to study the characterizations of John spaces. We obtain five equivalent characterizations for length John spaces. As an application, we establish a dimension-free quasisymmetric invariance of length John spaces. This result is new also in the case of the Euclidean space.