Real Algebraic SurfacesThese are the notes for my lectures at the Trento summer school held September 1997. The aim of the lectures is to provide an introduction to real algebraic surfaces using the minimal model program.…János Kollár·Dec 2, 1997SaveLearn
Coupled Contact Systems and Rigidity of Maximal Dimensional Variations of Hodge StructureIn this article we prove that locally Griffiths' horizontal distribution on the period domain is given by a generalized version of the familiar contact differential system. As a consequence of…Richard Mayer·Nov 30, 1997SaveLearn
On the Euler Characteristic of Generalized Kummer VarietiesWe apply the Yau-Zaslow-Beauville method to compute the Euler characteristic of the generalized Kummer varieties attached to a complex abelian surface (a calculation also done by Goettsche and…Olivier Debarre·Nov 28, 1997SaveLearn
Minimal discrepancies of hypersurface singularitiesWe give an upper bound for the minimal discrepancies of hypersurface singularities. As an application, we show that Shokurov's conjecture is true for log-terminal threefolds.Vladimir Masek·Nov 26, 1997SaveLearn
Uniform Zariski's Theorem On Fundamental GroupsThe Zariski theorem says that for every hypersurface in a complex projective (resp. affine) space of dimension at least 3 and for every generic plane in the projective (resp. affine) space the…Shulim Kaliman·Nov 25, 1997SaveLearn
On the classification of hyperbolic root systems of the rank three. Part IIt was recently understood that from the point of view of automorphic Lorentzian Kac-Moody algebras and some aspects of Mirror Symmetry, interesting hyperbolic root systems should have restricted…Viacheslav V. Nikulin·Nov 25, 1997SaveLearn
The enumerative geometry of K3 surfaces and modular formsWe prove the conjectures of Yau-Zaslow and Gottsche concerning the number curves on K3 surfaces. Specifically, let X be a K3 surface and C be a holomorphic curve in X representing a primitive…Jim Bryan, Naichung Conan Leung·Nov 24, 1997SaveLearn
Quantum cohomology of the moduli space of stable bundles over a Riemann surfaceWe determine the quantum cohomology of the moduli space of odd degree rank two stable vector bundles over a Riemann surface Σ of any genus. This work together with dg-ga/9710029 prove that this…Vicente Muñoz·Nov 24, 1997SaveLearn
Classification of Exceptional Complements: Elliptic Curve CaseWe classify the log del Pezzo surface (S,B) of rank 1 with no 1-,2-,3-,4-, or 6-complements with the additional condition that B has one irreducible component C which is an elliptic curve, and that C…Terutake Abe·Nov 24, 1997SaveLearn
On moduli spaces of 4- or 5-instanton bundlesWe study the scheme of multi-jumping lines of an n-instanton bundle mainly for n≤ 5. We apply it to prove the irreducibility and smoothness of the moduli space of 5-instanton. Some particular…F. Han·Nov 21, 1997SaveLearn
Mathematical Instantons In Characteristic TwoOn P3, we show that mathematical instantons in characteristic two are unobstructed. We produce upper bounds for the dimension of the moduli space of stable rank two bundles on P3 in characteristic…A. P. Rao·Nov 20, 1997SaveLearn
Cycles on Siegel 3-folds and derivatives of Eisenstein seriesWe consider the Siegel modular variety of genus 2 and a p-integral model of it for a good prime p>2, which parametrizes principally polarized abelian varieties of dimension two with a level…S. Kudla, M. Rapoport·Nov 20, 1997SaveLearn
Equations of the moduli of pointed curves in the infinite GrassmannianThe main result of this paper is the explicit computation of the equations defining the moduli space of triples (C,p,z) (where C is an integral and complete algebraic curve, p a smooth rational…J. M. Muñoz Porras, F. J. Plaza Martín·Nov 19, 1997SaveLearn
Cellular Resolutions of Monomial ModulesWe construct a canonical free resolution for arbitrary monomial modules and lattice ideals. This includes monomial ideals and defining ideals of toric varieties, and it generalizes our joint results…Dave Bayer, Bernd Sturmfels·Nov 19, 1997SaveLearn
A geometric approach to the fundamental lemma for unitary groupsWe consider from a geometric point of view the conjectural fundamental lemma of Langlands and Shelstad for unitary groups over a local field of positive characteristic. We introduce projective…G. Laumon, M. Rapoport·Nov 19, 1997SaveLearn
Semistable reduction in characteristic 0 for families of surfaces and three-foldsLet F:X->B be a morphism of varieties in characteristic zero. The problem of semistable reduction of F was stated as a problem in the combinatorics of polyhedral complexes by Abramovich and Karu…Kalle Karu·Nov 17, 1997SaveLearn
Stringy Hodge numbers and Virasoro algebraLet X be an arbitrary smooth n-dimensional projective variety. It was discovered by Libgober and Wood that the product of the Chern classes c1(X)cn-1(X) depends only on the Hodge numbers of…Victor V. Batyrev·Nov 16, 1997SaveLearn
On a conjecture of LangeLet C be a projective smooth curve of genus g> 1. Let E be a vector bundle of rank r on C. For each integer r'<r, associate to E the invariant sr'(E)=r'deg(E)-rdeg(E') where…B. Russo, M. Teixidor i Bigas·Nov 14, 1997SaveLearn
On the theta divisor of SU(2,1)Let SU(2,1) be the moduli space of stable rank two vector bundles having fixed determinant of odd degree over a compact Riemann surface C. In this paper it is shown that the Theta divisor of SU(2,1)…Sonia Brivio, Alessandro Verra·Nov 13, 1997SaveLearn
Boundary Manifolds of Line ArrangementsIn this paper we describe the complement of real line arrangements in the complex plane in terms of the boundary three-manifold of the line arrangement. We show that the boundary manifold of any line…Eriko Hironaka·Nov 12, 1997SaveLearn
Topological Triviality of μ-constant Deformations of Type f(x) + tg(x)We show that every μ-constant family of isolated hypersurface singularities of type f(x) + tg(x), where t is a parameter, is topologically trivial. In the proof we construct explicitely a vector…Adam Parusinski·Nov 11, 1997SaveLearn
First quantum correction for the moduli space of stable bundles over a Riemann surfaceWe compute some Gromov-Witten invariants of the moduli space of odd degree rank two stable vector bundles over a Riemann surface of any genus. Next we find the first correction term for the quantum…Vicente Muñoz·Nov 11, 1997SaveLearn
A conjectural generating function for numbers of curves on surfacesI give a conjectural generating function for the numbers of δ-nodal curves in a linear system of dimension δ on an algebraic surface. It reproduces the results of Vainsencher for the case $δ…Lothar Goettsche·Nov 11, 1997SaveLearn
Constructing curves over finite fields with many points by solving linear equationsIn this note is we exhibit an elementary method to construct explicitly curves over finite fields with many points. Despite its elementary character the method is very efficient and can be regarded…Gerard van der Geer, Marcel van der Vlugt·Nov 10, 1997SaveLearn
Semiinfinite Flags. II. Local and Global Intersection Cohomology of Quasimaps' SpacesFor a simple algebraic group G we study the space Q of Quasimaps from the projective line C to the flag variety of G. We prove that the global Intersection Cohomology of Q carries a natural…Boris Feigin, Michael Finkelberg, Alexander Kuznetsov et al.·Nov 8, 1997SaveLearn