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On uniqueness of branching to fixed point Lie subalgebras

  • Santosh Nadimpalli and Santosha Pattanayak ORCID logo EMAIL logo
Published/Copyright: September 30, 2022

Abstract

Let 𝔤 be a complex semisimple Lie algebra and let θ be a finite-order automorphism of 𝔤 . Let 𝔤 0 be the subalgebra { X 𝔤 : θ ( X ) = X } . In this article, we study for which pairs ( V 1 , V 2 ) , consisting of two irreducible finite-dimensional representations of 𝔤 , we have

res 𝔤 0 V 1 res 𝔤 0 V 2 .

In many cases, we show that V 1 and V 2 have isomorphic restrictions to 𝔤 0 if and only if V 1 is isomorphic to V 2 σ for some outer automorphism σ of 𝔤 .

MSC 2010: 17B10; 20G05; 22E46

Communicated by Jan Frahm


Acknowledgements

We would like to thank C. S. Rajan for his comments on this work and his encouragement. We would like to thank R. Venkatesh for some discussions. We also thank the anonymous referee for many valuable comments.

References

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Received: 2022-04-23
Revised: 2022-07-20
Published Online: 2022-09-30
Published in Print: 2022-11-01

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