Algebras and Representation Theory

, Volume 21, Issue 2, pp 399–417 | Cite as

Separable Commutative Rings in the Stable Module Category of Cyclic Groups

  • Paul Balmer
  • Jon F. Carlson


We prove that the only separable commutative ring-objects in the stable module category of a finite cyclic p-group G are the ones corresponding to subgroups of G. We also describe the tensor-closure of the Kelly radical of the module category and of the stable module category of any finite group.


Separable Etale Ring-object Stable category 

Mathematics Subject Classification (2010)

20C20 14F20 18E30 


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Both authors would like to thank Bielefeld University for its support and kind hospitality during a visit when this work was undertaken. We are also thankful to Danny Krashen, Akhil Mathew and Greg Stevenson for valuable discussions.


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© Springer Science+Business Media B.V. 2017

Authors and Affiliations

  1. 1.Mathematics DepartmentUCLALos AngelesUSA
  2. 2.Department of MathematicsUniversity of GeorgiaAthensUSA

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