215 citations · 807 across the 39 of their papers we have counts for
39 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…
Classification of multiplicity free quasi-Hamiltonian manifolds
Friedrich Knop
A quasi-Hamiltonian manifold is called multiplicity free if all of its symplectic reductions are 0-dimensional. In this paper, we classify compact, multiplicity free, twisted quasi…
Multiplicities and dimensions in enveloping tensor categories
Friedrich Knop
In the previous paper arxiv:math/0610552 semisimple tensor categories were constructed out of certain regular Mal'cev categories. In this paper, we calculate the tensor product mul…
The subobject decomposition in enveloping tensor categories
Friedrich Knop
To every regular category equipped with a degree function one can attach a pseudo-abelian tensor category . We show that the generatin…
Complexity of actions over perfect fields
Friedrich Knop, Vladimir S. Zhgoon
Let be a connected reductive group over a perfect field acting on an algebraic variety and let be a minimal parabolic subgroup of . For -spherical -varieti…
(Quasi-)Hamiltonian manifolds of cohomogeneity one
Friedrich Knop, Kay Paulus
We classify compact, connected Hamiltonian and quasi-Hamiltonian manifolds of cohomogeneity one (which is the same as being multiplicity free of rank one). Here the group acting is…