Defects of cusp singularities and the classification of Hilbert modular threefolds

1992 ◽  
Vol 292 (1) ◽  
pp. 1-12 ◽  
Author(s):  
H. G. Grundman
Keyword(s):  
Hilbert Modular ◽  
Cusp Singularities ◽  
Modular Threefolds

On the classification of Hilbert modular threefolds

1991 ◽  
Vol 72 (1) ◽  
pp. 297-305 ◽  
Author(s):  
H. G. Grundman
Keyword(s):  
Hilbert Modular ◽  
Modular Threefolds

scholarly journals Nonrational Hilbert Modular Threefolds

2000 ◽  
Vol 83 (1) ◽  
pp. 50-58 ◽  
Author(s):  
H.G Grundman
Keyword(s):  
Hilbert Modular ◽  
Modular Threefolds

scholarly journals Minimal Siegel modular threefolds

1998 ◽  
Vol 123 (3) ◽  
pp. 461-485 ◽  
Author(s):  
VALERI GRITSENKO ◽  
KLAUS HULEK
Keyword(s):  
Difficult Problem ◽  
Kodaira Dimension ◽  
Abelian Surfaces ◽  
Starting Point ◽  
Hilbert Modular Surfaces ◽  
Hilbert Modular ◽  
Kummer Surfaces ◽  
Torelli Theorem ◽  
Ramification Locus ◽  
Modular Threefolds

The starting point of this paper is the maximal extension Γ*t of Γt, the subgroup of Sp4(ℚ) which is conjugate to the paramodular group. Correspondingly we call the quotient [Ascr ]*t=Γ*t\ℍ2 the minimal Siegel modular threefold. The space [Ascr ]*t and the intermediate spaces between [Ascr ]t=Γt\ℍ2 which is the space of (1, t)-polarized abelian surfaces and [Ascr ]*t have not yet been studied in any detail. Using the Torelli theorem we first prove that [Ascr ]*t can be interpreted as the space of Kummer surfaces of (1, t)-polarized abelian surfaces and that a certain degree 2 quotient of [Ascr ]t which lies over [Ascr ]*t is a moduli space of lattice polarized K3 surfaces. Using the action of Γ*t on the space of Jacobi forms we show that many spaces between [Ascr ]t and [Ascr ]*t possess a non-trivial 3-form, i.e. the Kodaira dimension of these spaces is non-negative. It seems a difficult problem to compute the Kodaira dimension of the spaces [Ascr ]*t themselves. As a first necessary step in this direction we determine the divisorial part of the ramification locus of the finite map [Ascr ]t→[Ascr ]*t. This is a union of Humbert surfaces which can be interpreted as Hilbert modular surfaces.

Defect series and nonrational Hilbert modular threefolds

1994 ◽  
Vol 300 (1) ◽  
pp. 77-88 ◽  
Author(s):  
H. G. Grundman
Keyword(s):  
Hilbert Modular ◽  
Modular Threefolds

scholarly journals Hilbert modular surfaces and the classification of algebraic surfaces

1974 ◽  
Vol 23 (1) ◽  
pp. 1-29 ◽  
Author(s):  
F. Hirzebruch ◽  
A. Van de Ven
Keyword(s):  
Algebraic Surfaces ◽  
Hilbert Modular Surfaces ◽  
Hilbert Modular
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