AIMS Mathematics (May 2024)
The properties of generalized John domains in metric spaces
Abstract
In this paper, we studied the properties of generalized John domains in metric space. We prove that a domain $ D $ is a $ \varphi $-John domain if, and only if, $ D\backslash P $ is a $ \varphi' $-John domain, where $ P $ is a subset of $ D $ containing finitely many points of $ D $. Meanwhile, we also showed that the union of $ \varphi $-John domains is a $ \varphi'' $-John domain in metric space.
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