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arXiv · 2102.02112

New definitions of Alexandrov space and applications

Shengqi Hu·Xiaole Su·Yusheng Wang
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Abstract

In this paper we show that, in the definition of Alexandrov spaces with lower or upper curvature bound, the original conditions can be replaced with much weaker ones. For the purpose, we introduce `imaginary' comparison angles (and `imaginary' angles), and the right or left bounded second derivative in the support sense. As applications, we provide new proofs for the Doubling Theorem, and the Globalization Theorem for complete or geodesic Alexandrov spaces with lower curvature bound.

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Shengqi Hu, Xiaole Su, Yusheng Wang. 2021-02-03. New definitions of Alexandrov space and applications. https://arxiv.org/abs/2102.02112

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