Base change of invariant subrings

The Total Coordinate Ring of a Wonderful Variety

We study the cone of effective divisors and the total coordinate ring of wonderful varieties, with applications to their automorphism group. We show that the total coordinate ring of any spherical variety is obtained from that of the associated wonderful variety by a base change of invariant subrings.

Equivariant total ring of fractions and factoriality of rings generated by semiinvariants

Let F be an affine flat group scheme over a commutative ring R, and S an F -algebra (an R-algebra on which F acts). We define an equivariant analogue QF (S) of the total ring of fractions Q(S) of S. It is the largest F -algebra T such that S ⊂ T ⊂ Q(S), and S is an F -subalgebra of T . We study some basic properties. Utilizing this machinery, we give some new criteria for factoriality (UFD prop...

Gorensteinness of Invariant Subrings of Quantum Algebras

We prove Auslander-Gorenstein and GKdim-Macaulay properties for certain invariant subrings of some quantum algebras, the Weyl algebras, and the universal enveloping algebras of finite dimensional Lie algebras.

Good Ltrations of Symmetric Algebras and Strong F -regularity of Invariant Subrings Dedicated to Professor Buchsbaum

In this paper, we prove that a linear action of a reductive group on a polynomial ring with good ltrations over a eld of characteristic p > 0 yields a strongly F-regular (in particular, Cohen-Macaulay) invariant subring. The strongly F-regular property of some known examples of invariant subrings, such as the coordinate rings of Schubert varieties in Grassmannians, are recovered. A similar resu...

Cohen-Macaulay and Gorenstein properties of invariant subrings