10 papers
Lower Bounds for the Generalized h-Vectors of Centrally Symmetric Polytopes
Annette A'Campo-Neuen
In a previous article, we proved tight lower bounds for the coefficients of the generalized -vector of a centrally symmetric rational polytope using intersection cohomology of t…
Orbit spaces of small tori
A. A'Campo-Neuen, J. Hausen
Consider an algebraic torus of small dimension acting on an open subset of a complex vector space, or more generally on a quasiaffine variety such that a separated orbit space exis…
Homogeneous Coordinates and Quotient Presentations for Toric Varieties
A. A'Campo-Neuen, J. Hausen, S. Schroeer
Generalizing cones over projective toric varieties, we present arbitrary toric varieties as quotients of quasiaffine toric varieties. Such quotient presentations correspond to grou…
Weakly Proper Toric Quotients
Annette A'Campo-Neuen
We consider subtorus actions on complex toric varieties. A natural candidate for a categorical quotient of such an action is the so-called toric quotient, a universal object constr…
Examples and Counterexamples for Existence of Categorical Quotients
A. A'Campo-Neuen, J. Hausen
We give examples for existence and non-existence of categorical quotients for algebraic group actions in the categories of algebraic varieties and prevarieties. All our examples ar…
Quotients of Divisorial Toric Varieties
A. A'Campo-Neuen, J. Hausen
We consider subtorus actions on divisorial toric varieties. Here divisoriality means that the variety has many Cartier divisors like quasiprojective and smooth ones. We characteriz…