8 citations · 19 across the 19 of their papers we have counts for
28 papers
Spherical subgroups in reductive algebraic groups
Friedrich Knop, Gerhard Roehrle
In a paper from 2015, we determined all spherical affine homogeneous varieties for simple algebraic groups in arbitrary characteristic. The present paper extends this classificatio…
Semisimplification for Subgroups of Reductive Algebraic Groups
Michael Bate, Benjamin Martin, Gerhard Roehrle
Let be a reductive algebraic group---possibly non-connected---over a field and let be a subgroup of . If then there is a degeneration process for obtaining…
Some remarks on free arrangements
Torsten Hoge, Gerhard Roehrle
We exhibit a particular free subarrangement of a certain restriction of the Weyl arrangement of type and use it to give an affirmative answer to a recent conjecture by T.~Abe…
Relative complete reducibility and normalised subgroups
Maike Gruchot, Alastair Litterick, Gerhard Roehrle
We study a relative variant of Serre's notion of -complete reducibility for a reductive algebraic group . We let be a reductive subgroup of , and consider subgroups of…
On relative complete reducibility
Christopher Attenborough, Michael Bate, Maike Gruchot +2
Let be a reductive subgroup of a reductive group over an algebraically closed field . The notion of relative complete reducibility, introduced in previous work of Bate-M…
Restrictions of aspherical arrangements
Nils Amend, Tilman Moeller, Gerhard Roehrle
In this note we present examples of -arrangements which admit a restriction which fails to be . This shows that asphericity is not hereditary among hyperplane arran…