Covering instability for the existence of positive scalar curvature metrics

Fuente: arXiv
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Autores principales: Li, Chao, Zhang, Boyu
Formato: Preprint
Publicado: 2025
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author Li, Chao
Zhang, Boyu
author_facet Li, Chao
Zhang, Boyu
contents We show that a closed non-orientable $3$-manifold admits a positive scalar curvature metric if and only if its orientation double cover does; however, for each $4\le n\le 7$, there exist infinitely many smooth non-orientable $n$-manifolds $M$ that are mutually non-homotopy equivalent, such that the orientation double cover of $M$ admits positive scalar curvature metrics, but every closed smooth manifold that is homotopy equivalent to $M$ cannot admit positive scalar curvature metrics. These examples were first introduced by Alpert-Balitskiy-Guth in the study of Urysohn widths. To prove the nonexistence result, we extend the Schoen-Yau inductive descent approach to non-orientable manifolds. We also discuss band width estimates and the notion of enlargeability for non-orientable PSC manifolds.
format Preprint
id arxiv_https___arxiv_org_abs_2506_13885
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Covering instability for the existence of positive scalar curvature metrics
Li, Chao
Zhang, Boyu
Differential Geometry
Geometric Topology
Metric Geometry
We show that a closed non-orientable $3$-manifold admits a positive scalar curvature metric if and only if its orientation double cover does; however, for each $4\le n\le 7$, there exist infinitely many smooth non-orientable $n$-manifolds $M$ that are mutually non-homotopy equivalent, such that the orientation double cover of $M$ admits positive scalar curvature metrics, but every closed smooth manifold that is homotopy equivalent to $M$ cannot admit positive scalar curvature metrics. These examples were first introduced by Alpert-Balitskiy-Guth in the study of Urysohn widths. To prove the nonexistence result, we extend the Schoen-Yau inductive descent approach to non-orientable manifolds. We also discuss band width estimates and the notion of enlargeability for non-orientable PSC manifolds.
title Covering instability for the existence of positive scalar curvature metrics
topic Differential Geometry
Geometric Topology
Metric Geometry
url https://arxiv.org/abs/2506.13885