Transformation Groups

, Volume 19, Issue 1, pp 283–287 | Cite as

An integrality theorem of Grosshans over arbitrary base ring

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Abstract

We revisit a theorem of Grosshans and show that it holds over arbitrary commutative base ring k. One considers a split reductive group scheme G acting on a k-algebra A and leaving invariant a subalgebra R. Let U be the unipotent radical of a split Borel subgroup scheme. If RU = AU then the conclusion is that A is integral over R.

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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  1. 1.Mathematisch InstituutUtrechtThe Netherlands

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