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Lajos Molnár
A new look at local maps on algebraic structures of matrices and operators
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Published: |
March 9, 2022. |
Keywords: |
Local maps, reflexive closures, automorphisms, derivations, operator algebras, matrix algebras, groups of operators and matrices, function algebras. |
Subject: |
Primary: 47B49, 46L40, 46L57. Secondary: 47B47, 47B65. |
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Abstract
In a very general setting, we introduce a new type of local maps, a new sort of reflexive closure of a given class of transformations relative to a given operation that we call operational reflexive closure, and a corresponding concept of reflexivity. We calculate the operational reflexive closures of some important classes of transformations and significantly strengthen former 2-reflexivity results concerning the automorphism groups of various operator structures. A typical new result is this: if φ is a map from the unitary group over a separable infinite dimensional Hilbert space into itself with the property that for any pair V,W of unitaries there is a group automorphism αV,W of the unitary group such that φ(V)φ(W)=αV,W(VW), then either φ itself or -φ is a group automorphism. This result substantially generalizes a former one on the 2-reflexivity of the automorphism group of the unitary group.
We also present open problems and questions for further study.
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Acknowledgements
The author acknowledges supports from the Ministry for Innovation and Technology, Hungary,
grant NKFIH-1279-2/2020 and from the National Research, Development and Innovation Office of Hungary, NKFIH, Grant No. K115383, K134944.
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Author information
Lajos Molnár:
Bolyai Institute
University of Szeged
Aradi vértanúk tere 1.
H-6720 Szeged, Hungary, and
Department of Analysis, Institute of Mathematics
Budapest University of Technology and Economics
Muegyetem rkp. 3.
H-1111 Budapest, Hungary
molnarl@math.u-szeged.hu
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