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Simple semigroup graded rings

Nystedt, Patrik and Öinert, Johan LU (2015) In Journal of Algebra and Its Applications 14(7).
Abstract
We show that if R is a, not necessarily unital, ring graded by a semigroup G equipped with an idempotent e such that G is cancellative at e, the nonzero elements of eGe form a hypercentral group and R-e has a nonzero idempotent f, then R is simple if and only if it is graded simple and the center of the corner subring fR(eGe)f is a field. This is a generalization of a result of Jespers' on the simplicity of a unital ring graded by a hypercentral group. We apply our result to partial skew group rings and obtain necessary and sufficient conditions for the simplicity of a, not necessarily unital, partial skew group ring by a hypercentral group. Thereby, we generalize a very recent result of Goncalves'. We also point out how Jespers' result... (More)
We show that if R is a, not necessarily unital, ring graded by a semigroup G equipped with an idempotent e such that G is cancellative at e, the nonzero elements of eGe form a hypercentral group and R-e has a nonzero idempotent f, then R is simple if and only if it is graded simple and the center of the corner subring fR(eGe)f is a field. This is a generalization of a result of Jespers' on the simplicity of a unital ring graded by a hypercentral group. We apply our result to partial skew group rings and obtain necessary and sufficient conditions for the simplicity of a, not necessarily unital, partial skew group ring by a hypercentral group. Thereby, we generalize a very recent result of Goncalves'. We also point out how Jespers' result immediately implies a generalization of a simplicity result, recently obtained by Baraviera, Cortes and Soares, for crossed products by twisted partial actions. (Less)
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author
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organization
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type
Contribution to journal
publication status
published
subject
keywords
Semigroup graded ring, partial skew group ring, simplicity
in
Journal of Algebra and Its Applications
volume
14
issue
7
article number
1550102
publisher
World Scientific Publishing
external identifiers
  • wos:000353552200006
  • scopus:84928555107
ISSN
0219-4988
DOI
10.1142/S0219498815501029
language
English
LU publication?
yes
id
30488f71-5a66-4169-b32e-ee753a9d8872 (old id 5385887)
date added to LUP
2016-04-01 10:52:16
date last changed
2022-03-12 17:50:47
@article{30488f71-5a66-4169-b32e-ee753a9d8872,
  abstract     = {{We show that if R is a, not necessarily unital, ring graded by a semigroup G equipped with an idempotent e such that G is cancellative at e, the nonzero elements of eGe form a hypercentral group and R-e has a nonzero idempotent f, then R is simple if and only if it is graded simple and the center of the corner subring fR(eGe)f is a field. This is a generalization of a result of Jespers' on the simplicity of a unital ring graded by a hypercentral group. We apply our result to partial skew group rings and obtain necessary and sufficient conditions for the simplicity of a, not necessarily unital, partial skew group ring by a hypercentral group. Thereby, we generalize a very recent result of Goncalves'. We also point out how Jespers' result immediately implies a generalization of a simplicity result, recently obtained by Baraviera, Cortes and Soares, for crossed products by twisted partial actions.}},
  author       = {{Nystedt, Patrik and Öinert, Johan}},
  issn         = {{0219-4988}},
  keywords     = {{Semigroup graded ring; partial skew group ring; simplicity}},
  language     = {{eng}},
  number       = {{7}},
  publisher    = {{World Scientific Publishing}},
  series       = {{Journal of Algebra and Its Applications}},
  title        = {{Simple semigroup graded rings}},
  url          = {{http://dx.doi.org/10.1142/S0219498815501029}},
  doi          = {{10.1142/S0219498815501029}},
  volume       = {{14}},
  year         = {{2015}},
}