No Connectedness Lemma for Alexandrov spaces

Jan Nienhaus; Dennis Wulle

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arXiv · 2610.37476

No Connectedness Lemma for Alexandrov spaces

Jan Nienhaus·Dennis Wulle

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Abstract

Since its introduction in 2003, Wilking's Connectedness Lemma has become a powerful tool in the study of manifolds with positive sectional curvature. In recent work of the authors, this has been extended to orbifolds. The purpose of this note is to exhibit counterexamples in the class of Alexandrov spaces for the Connectedness Lemma in both its ordinary and dual formulation. This answers a 2007 question of Wilking.

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Jan Nienhaus, Dennis Wulle. 2026-10-27. No Connectedness Lemma for Alexandrov spaces. https://arxiv.org/abs/2610.37476

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