31 citations · 230 across the 65 of their papers we have counts for
8 papers · 1 filter
Degenerations of (1,3) abelian surfaces and Kummer surfaces
K. Hulek, I. Nieto, G. K. Sankaran
We continue our study of the geometry of Nieto's quintic threefold, looking at degenerate surfaces that correspond to certain loci and showing how they arise from a toroidal compac…
Heisenberg-invariant Kummer surfaces
K. Hulek, I. Nieto, G. K. Sankaran
We study the geometry of Nieto's quintic threefold (Barth & Nieto, J. Alg. Geom. 3, 1994) and the Kummer and abelian surfaces that correspond to special loci.
Nef Divisors on Moduli Spaces of Abelian Varieties
Klaus Hulek
We determine the cone of nef divisors on the Voronoi compactification A_g^* of the moduli space A_g of principally polarized abelian varieties of dimension g for genus g=2,3. As a…
A Remark on the Geometry of Elliptic Scrolls and Bielliptic Surfaces
C. Ciliberto, K. Hulek
The union of two quintic elliptic scrolls in P^4 intersecting transversally along an elliptic normal quintic curve is a singular surface Z which behaves numerically like a biellipt…
Embeddings of curves and surfaces
F. Catanese, M. Franciosi, K. Hulek +1
We prove a general embedding theorem for Cohen--Macaulay curves (possibly nonreduced), and deduce a cheap proof of the standard results on pluricanonical embeddings of surfaces, as…
Syzygies of Abelian and Bielliptic Surfaces in P^4
Alf Aure, Wolfram Decker, Klaus Hulek +2
So far only six families of smooth irregular surfaces are known to exist in P^4 (up to pullbacks by suitable finite covers of P^4). These are the elliptic quintic scrolls, the mini…
Minimal Siegel modular threefolds
Valeri Gritsenko, Klaus Hulek
In this paper we study the maximal extension of the subgroup of $\operatorname{Sp}_4 (\bq)$ which is conjugate to the paramodular group. The index of this extension i…
The Geometry of Bielliptic Surfaces in P^4
A. Aure, W. Decker, K. Hulek +2
In 1988 Serrano \cite{Ser}, using Reider's method, discovered a minimal bielliptic surface in $\PP^4$. Actually he showed that there is a unique family of such surfaces and that th…