John圆与双曲度量

摘要

We disscuss the geometric properties of John disks by using the hyperbolic metric, and establish a necessary and sufficient condition for John disk with the aid of GehringHayman inequality.%利用双曲度量讨论了John圆的几何性质,借助于Gehring-Hayman不等式建立了John圆的一个充要条件.