Class Groups of Localities of Rings of Invariants of Reductive Algebraic Groups.
Cohen-Macaulayness of modules of covariants.
Cohomologie des groupes et corps d'invariants multiplicatifs.
Comportement asymptotique des dimensions des covariants
Constructive geometric invariant theory for certain nonreductive groups
Constructive invariant theory for tori
Consider a rational representation of an algebraic torus on a vector space . Suppose that is a homogeneous minimal generating set for the ring of invariants, . New upper bounds are derived for the number . These bounds are expressed in terms of the volume of the convex hull of the weights of and other geometric data. Also an algorithm is described for constructing an (essentially unique) partial set of generators consisting of monomials and such that is integral over .
Correction to "Corrections to the paper «A remark on the orbit spaces under multiplicative group actions»" (Colloquium Mathematicum 57.2 (1989), pp. 361--362)
Corrections to the paper "A remark on the orbit spaces under multiplicative group actions''
Cyclic coverings of abelian varities and the Goryachev-Chaplygin top.
Decomposable ternary cubics.
Deformation of the nilpotent zero scheme and the intersection ring of invariant subvarieties.
Deformations of theta divisors and the rank 4 quadrics problem
Deligne-Lusztig restriction of a Gelfand-Graev module
Using Deodhar’s decomposition of a double Schubert cell, we study the regular representations of finite groups of Lie type arising in the cohomology of Deligne-Lusztig varieties associated to tori. We deduce that the Deligne-Lusztig restriction of a Gelfand-Graev module is a shifted Gelfand-Graev module.
Der Grad erzeugender Funktionen von Invariantenringen.
Derivations of Negative Weight and Non-Smoothability of Certain Singularities.
Endliche Automorphismengruppen analytischer C-Algebren und ihre Invarianten.
Etale covers, bimodules and differential operators.
Existence de faisceaux réflexifs de rang deux sur à bonne cohomologie
Factorisation de certains morphismes birationnels
Factorization of point configurations, cyclic covers, and conformal blocks
We describe a relation between the invariants of ordered points in projective -space and of points contained in a union of two linear subspaces. This yields an attaching map for GIT quotients parameterizing point configurations in these spaces, and we show that it respects the Segre product of the natural GIT polarizations. Associated to a configuration supported on a rational normal curve is a cyclic cover, and we show that if the branch points are weighted by the GIT linearization and the rational...