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RELATING TENSOR STRUCTURES ON REPRESENTATIONS OF GENERAL LINEAR AND SYMMETRIC GROUPS
For polynomial representations of GL n of a fixed degree, H. Krause defined a new “internal tensor product” using the language of strict polynomial functors. We show that over an arbitrary commutative base ring k , the Schur functor carries this internal tensor product to the usual Kronecker tensor...
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Published in: | Transformation groups 2018-06, Vol.23 (2), p.437-461 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | For polynomial representations of GL
n
of a
fixed
degree, H. Krause defined a new “internal tensor product” using the language of strict polynomial functors. We show that over an arbitrary commutative base ring
k
, the Schur functor carries this internal tensor product to the usual Kronecker tensor product of symmetric group representations. This is true even at the level of derived categories. The new tensor product is a substantial enrichment of the Kronecker tensor product. E.g., in modular representation theory it brings in homological phenomena not visible on the symmetric group side. We calculate the internal tensor product over any commutative ring
k
in several interesting cases involving classical functors and the Weyl functors. We show an application to the Kronecker problem in characteristic zero when one partition has two rows or is a hook. |
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ISSN: | 1083-4362 1531-586X |
DOI: | 10.1007/s00031-018-9481-x |