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math.RA2025
On a question by Roggenkamp about group algebras
Dylan Johnston, Dmitriy Rumynin
We investigate whether the group algebra of a finite group over a localisation of the integers is semiperfect. The main result is a necessary and sufficient arithmetic criterion in…
math.RA2025
Global Representation Ring and Knutson Index
Dylan Johnston, Diego MartÃn Duro, Dmitriy Rumynin
Global representation rings were discovered by Sarah Witherspoon in 1995 and the Knutson Index was introduced by the second author in 2022. In the present paper we introduce the Kn…