11 citations · 47 across the 11 of their papers we have counts for
11 papers
Reductivity properties over an affine base
Wilberd van der Kallen
When the base ring is not a field, power reductivity of a group scheme is a basic notion, intimately tied with finite generation of subrings of invariants. Geometric reductivity is…
Rational cohomology of an algebra need not be detected by Frobenius kernels
Wilberd van der Kallen
Friedrich Knop has given an example of a polynomial algebra A in characteristic two with an unusual SL_2 action. We exhibit a nontrivial class in H^1(SL_2,A), not detected by Frobe…
Addendum to: A simultaneous Frobenius splitting for closures of conjugacy classes of nilpotent matrices, by V. B. Mehta and Wilberd van der Kallen
Wilberd van der Kallen
Prompted by an exercise in the Brion Kumar book on Frobenius splittings, we show compatibility with a few more subvarieties of the Frobenius splitting from our 1992 paper.
Finite Schur filtration dimension for modules over an algebra with Schur filtration
Vasudevan Srinivas, Wilberd van der Kallen
Let G be GL_N or SL_N as reductive linear algebraic group over a field k of positive characteristic p. We prove several results that were previously established only when N < 6 or…
Finite good filtration dimension for modules over an algebra with good filtration
Wilberd van der Kallen
Let G be a connected reductive linear algebraic group over a field k of characteristic p>0. Let p be large enough with respect to the root system. We show that if a finitely genera…
A reductive group with finitely generated cohomology algebras
Wilberd van der Kallen
Let be the linear algebraic group over a field of characteristic two. Let be a finitely generated commutative -algebra on which acts rationally by -alg…