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New York Journal of Mathematics
Volume 31 (2025), 837-856

  

Stefan Wagner

On noncommutative frame bundles

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Published: June 10, 2025.
Keywords: Noncommutative principal bundle, unitary tensor functor, correspondence, frame bundle, associated vector bundle, rotation group.
Subject [2020]: Primary 58B34, 46L85; Secondary 55R10.

Abstract
The question of whether a right Hilbert bimodule admits a noncommutative frame bundle - i.e, a C*-algebraic noncommutative principal bundle with which the right Hilbert bimodule is associated via some fundamental representation - is both pivotal and difficult. In this paper, we contribute to this topic by providing an axiomatic characterization of a right Hilbert bimodule, let's say M, that ensures the existence of a unique (up to isomorphism) free C*-dynamical system (AM,SO(n),αM) with the property that its associated noncommutative vector bundle, with respect to the standard representation of SO(n), is isomorphic to M. Our approach is inspired by potential applications in noncommutative Riemannian spin geometry.

Acknowledgements

The author wishes to express his thanks to Ludwik Dabrowski, Karl-Hermann Neeb, and Sergey Neshveyev, for helpful conversations and correspondence, and he especially thanks Kay Schwieger for numerous technical conversations over the last several years that have indelibly shaped this work. The author also thanks the anonymous referee for valuable suggestions that helped improve the exposition.


Author information

Stefan Wagner
Department of Mathematics and Natural Sciences
Blekinge Institute of Technology
SE-37179 Karlskrona, Sweden

stefan.wagner@bth.se