Refocusing spacetimes need not be strongly refocusing

Fuente: arXiv
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Main Author: Bauermeister, Friedrich
Format: Preprint
Published: 2026
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author Bauermeister, Friedrich
author_facet Bauermeister, Friedrich
contents We prove that there are globally hyperbolic spacetimes $(X,g)$ which are refocusing but not strongly refocusing. In fact, every globally hyperbolic strongly refocusing spacetime of dimension at least $3$ admits globally hyperbolic metrics which are refocusing but not strongly refocusing. This answers a question by Chernov, Kinlaw, and Sadykov. We then prove that globally hyperbolic spacetimes which are Legendrian refocusing (a notion introduced in this paper) admit globally hyperbolic strongly refocusing metrics.
format Preprint
id arxiv_https___arxiv_org_abs_2605_21871
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Refocusing spacetimes need not be strongly refocusing
Bauermeister, Friedrich
Differential Geometry
General Relativity and Quantum Cosmology
Mathematical Physics
53C50 (Primary) 53C22, 58D17 (Secondary)
We prove that there are globally hyperbolic spacetimes $(X,g)$ which are refocusing but not strongly refocusing. In fact, every globally hyperbolic strongly refocusing spacetime of dimension at least $3$ admits globally hyperbolic metrics which are refocusing but not strongly refocusing. This answers a question by Chernov, Kinlaw, and Sadykov. We then prove that globally hyperbolic spacetimes which are Legendrian refocusing (a notion introduced in this paper) admit globally hyperbolic strongly refocusing metrics.
title Refocusing spacetimes need not be strongly refocusing
topic Differential Geometry
General Relativity and Quantum Cosmology
Mathematical Physics
53C50 (Primary) 53C22, 58D17 (Secondary)
url https://arxiv.org/abs/2605.21871