Genus one enumerative invariants in Pn with fixed j invariantWe prove recursive formulas for τd, the number of degree d elliptic curves with fixed j-invariant in Pn. We use analysis to relate the classical invariant τd to the genus one perturbed…Eleny Ionel·Aug 26, 1996SaveLearn
Hodge and Tate conjectures for hypergeometric sheavesA constructible sheaf corresponding to Gel'fand Zelevinski hypergeometric functions on a torus is called hypergeometric sheaf. We consider Hodge and Tate conjectrue for hypergeomtric sheaves.…Tomohide Terasoma·Aug 25, 1996SaveLearn
Intersection theory on moduli spaces of holomorphic bundles of arbitrary rank on a Riemann surfaceWe prove formulas (found by Witten in 1992 using physical methods) for intersection pairings in the cohomology of the moduli space M(n,d) of stable holomorphic vector bundles of rank n and degree d…Lisa C. Jeffrey, Frances C. Kirwan·Aug 23, 1996SaveLearn
Holomorphic bundles on O(-k) are algebraicWe show that holomorphic bundles on O(-k) for k > 0 are algebraic. We also show holomorphic bundles on O(-1) are trivial outside the zero section.Elizabeth Gasparim·Aug 23, 1996SaveLearn
Algebraic CutsLet X be a projective variety with a torus action, which for simplicity we assume to have dimension 1. If X is a smooth complex variety, then the geometric invariant theory quotient X//G can be…Dan Edidin, William Graham·Aug 23, 1996SaveLearn
The intersection form in the cohomology of the moduli space of genus 0 n-pointed curves H*(M0,n) and the explicit Künneth formula in quantum cohomologyWe prove a general formula for the intersection form of two arbitrary monomials in boundary divisors. Furthermore we present a tree basis of the cohomology of M0,n. With the help of…Ralph Kaufmann·Aug 22, 1996SaveLearn
Counting plane curves of any genusWe obtain a recursive formula answering the following question: How many irreducible, plane curves of degree d and (geometric) genus g pass through 3d-1+g general points in the plane? The formula is…Lucia Caporaso, Joe Harris·Aug 22, 1996SaveLearn
Parameter spaces for curves on surfaces and enumeration of rational curvesWe answer some enumerative questions about irreducible rational curves on Hirzebruch surfaces, by combining an idea of Kontsevich with the study of the geometry of certain natural parameter spaces.…Lucia Caporaso, Joe Harris·Aug 22, 1996SaveLearn
Enumerating curves on rational surfaces: the rational fibration methodA new, simple method to approach enumerative questions about rational curves on rational surfaces is described. Applications include a short proof of Kontsevich's formula for plane curves and a…Lucia Caporaso, Joe Harris·Aug 22, 1996SaveLearn
Rank Two Bundles on Algebraic Curves and Decoding of Goppa CodesWe study a connection between two topics: Decoding of Goppa codes arising from an algebraic curve, and rank two extensions of certain line bundles on the curve.Trygve Johnsen·Aug 21, 1996SaveLearn
Some adjunction-theoretic properties of codimension two nonsingular subvarieties of quadricsWe make precise the structure of the first two reduction morphisms associated with codimension two nonsingular subvarieties of quadrics n, n≥ 5. We give a coarse classification of the same…Mark Andrea A. de Cataldo·Aug 21, 1996SaveLearn
Codimension two nonsingular subvarieties of quadrics: scrolls and classification in degree d≤ 10Let X be a codimension two nonsingular subvariety of a nonsingular quadric n of dimension n≥ 5. We classify such subvarieties when they are scrolls. We also classify them when the degree…Mark Andrea A. de Cataldo·Aug 21, 1996SaveLearn
A finiteness theorem for low-codimensional nonsingular subvarieties of quadricsWe prove that there are only finitely many families of codimension two nonsingular subvarieties of quadrics n which are not of general type, for n=5 and n≥ 7. We prove a similar…Mark Andrea A. de Cataldo·Aug 21, 1996SaveLearn
The genus of curves on the three dimensional quadricBy means of an ad hoc modification of the so-called ``Castelnuovo-Harris analysis" we derive an upper bound for the genus of integral curves on the three dimensional nonsingular quadric…Mark Andrea A. de Cataldo·Aug 21, 1996SaveLearn
On the Thomae formula for ZN curvesWe shall give an elementary and rigorous proof of the Thomae formula for ZN curves which was discovered by Bershadsky and Radul. Instead of using the determinant of the Laplacian we use the…Atsushi Nakayashiki·Aug 20, 1996SaveLearn
Balanced VarietiesAfter the work of Bloch and Srinivas on correspondences and algebraic cycles we begin the study of a birational class of algebraic varieties determined by the property that a multiple of the diagonal…L. Barbieri-Viale·Aug 20, 1996SaveLearn
Complete intersections and rational equivalenceTwo cycles on a projective variety over an algebraically closed field are shown to be rationally equivalent if and only if their difference equals a difference of complete intersections of a certain…R. Barlow·Aug 20, 1996SaveLearn
Compactified jacobiansLet J be the jacobian of a reduced projective curve C with nodes only. 1) We give a simple and natural definition for its many compactifications and show the connection with various other definitions…Valery Alexeev·Aug 17, 1996SaveLearn
On Mumford's construction of degenerating abelian varietiesWe prove that a 1-dimnl family of abelian varieties with an ample sheaf defining principal polarization can be canonically compactified (after a finite base change) to a projective family with an…Valery Alexeev, Iku Nakamura·Aug 17, 1996SaveLearn
Log canonical singularities and complete moduli of stable pairs1) Assuming log Minimal Model Conjecture, we give a construction of a complete moduli space of stable log pairs of arbitrary dimension generalizing directly the space Mg,n of pointed stable…Valery Alexeev·Aug 17, 1996SaveLearn
Notes on stable maps and quantum cohomologyThese are notes from a jointly taught class at the University of Chicago and lectures by the first author in Santa Cruz. Topics covered include: construction of moduli spaces of stable maps,…W. Fulton, R. Pandharipande·Aug 15, 1996SaveLearn
Lower Bounds for diophantine ApproximationWe introduce a subexponential algorithm for geometric solving of multivariate polynomial equation systems whose bit complexity depends mainly on intrinsic geometric invariants of the solution set.…M. Giusti, J. Heintz, K. Hägele et al.·Aug 13, 1996SaveLearn
Residues in intersection homology and Lp-cohomologySuppose Mn+1 is a complex manifold and K is a hypersurface with isolated singularities. Let ω be a holomorphic form on M K with the first order pole on K. The Leray residue of such…Andrzej Weber·Aug 10, 1996SaveLearn
Vanishing Theorems and Syzygies for K3 Surfaces and Fano VarietiesIn this article we prove some strong vanishing theorems on K3 surfaces. As an aplication of them, we obtain higher syzygy results for K3 surfaces and Fano varieties.F. J. Gallego, B. P. Purnaprajna·Aug 7, 1996SaveLearn
The Geometry Underlying Mirror SymmetryThe recent result of Strominger, Yau and Zaslow relating mirror symmetry to the quantum field theory notion of T-duality is reinterpreted as providing a way of geometrically characterizing which…David R. Morrison·Aug 5, 1996SaveLearn