Dual varieties and the duality of the second fundamental formFirst, we consider a compact real-analytic irreducible subvariety M in a sphere and its dual variety M. We explain that two matrices of the second fundamental forms for both varieties M…Tohsuke Urabe·Feb 3, 1997SaveLearn
Residues and ResultantsResultants, Jacobians and residues are basic invariants of multivariate polynomial systems. We examine their interrelations in the context of toric geometry. The global residue in the torus, studied…Eduardo Cattani, Alicia Dickenstein, Bernd Sturmfels·Jan 31, 1997SaveLearn
Counting rational curves on K3 surfacesThe aim of these notes is to explain the remarkable formula found by Yau and Zaslow to express the number of rational curves on a K3 surface. Projective K3 surfaces fall into countably many families…Arnaud Beauville·Jan 30, 1997SaveLearn
Exemples de composantes irréductibles et non réduites du schéma de Hilbert des courbes lisses et connexes de P3 (II)Soit Hd,g le schéma de Hilbert des courbes lisses et connexes de degré d et genre g de l'espace projectif P3 sur un corps k algébriquement clos de caractéristique nulle. Le…Said Azziz·Jan 29, 1997SaveLearn
Heights and Geometric Invariant TheoryLet K be a number field, be its ring of integers. We introduce the notion of compactified representation of GLN() and, we see how to associate to a hermitian vector bundle over…Carlo Gasbarri·Jan 29, 1997SaveLearn
A mirror theorem for toric complete intersectionsWe prove a generalized mirror conjecture for non-negative complete intersections in symplectic toric manifolds. Namely, we express solutions of the PDE system describing quantum cohomology of such a…Alexander Givental·Jan 27, 1997SaveLearn
A remark on an algebraic Riemann-Roch formula for flat bundlesWe propose an algebraic Riemann-Roch formula for moving flat bundles on contant families in characteristic zero with values in the ring of algebraic differential characters. This formula lifts…Hélène Esnault·Jan 27, 1997SaveLearn
Geometry of cohomology support loci II: integrability of Hitchin's mapIn very rough terms, the main theorem is that the set, which consists of semistable vector bundles with trivial rational Chern classes and nontrivial kth cohomology on a smooth complex projective…Donu Arapura·Jan 26, 1997SaveLearn
Families of K3 surfacesWe use automorphic forms to prove that a compact family of Kaehler K3 surfaces with constant Picard number is isotrivial.Richard E. Borcherds, Ludmil Katzarkov, Tony Pantev et al.·Jan 26, 1997SaveLearn
A Prym construction for the cohomology of a cubic hypersurfaceMumford defined a natural isomorphism between the intermediate jacobian of a conic-bundle over P2 and the Prym variety of a naturally defined étale double cover of the discrminant curve of the…E. Izadi·Jan 25, 1997SaveLearn
K3 surfaces with interesting groups of automorphismsBy the fundamental result of I.I. Piatetsky-Shapiro and I.R. Shafarevich (1971), the automorphism group Aut(X) of a K3 surface X over C and its action on the Picard lattice SX are prescribed by the…Viacheslav V. Nikulin·Jan 24, 1997SaveLearn
Subvarieties of SUC(2) and 2θ-divisors in the JacobianWe explore some of the interplay between Brill-Noether subvarieties of the moduli space SUC(2,K) of rank 2 bundles with canonical determinant on a smooth projective curve and 2θdivisors, via the…W. M. Oxbury, C. Pauly, E. Previato·Jan 23, 1997SaveLearn
On the singularities of the theta divisors on JacobiansWe study the intersection cohomology of the theta divisors on Jacobians of nonhyperelliptic curves.P. Bressler, J. -L. Brylinski·Jan 22, 1997SaveLearn
Adelic Formulas for Gamma- and Beta-functions in Algebraic Numbers FieldsOn the basis of analysis on the adele ring of any algebraic numbers field (Tate's formula) a regularization for divergent adelic products of gamma- and beta-functions for all completions of this…V. S. Vladimirov·Jan 20, 1997SaveLearn
On Hitchin's ConnectionThe aim of this paper is to give an explicit expression for Hitchin's connection in the case of rank 2 bundles with trivial determinant over curves of genus 2. We recall the definition of this…Bert van Geemen, Aise Johan de Jong·Jan 18, 1997SaveLearn
On the cone of divisors of Calabi-Yau fiber spacesWe prove some version of Morrison's conjecture on the cone of divisors for Calabi-Yau fiber spaces with non-trivial base pace whose total space is 3-dimensional.Yujiro Kawamata·Jan 13, 1997SaveLearn
Quotients par des groupes non réductifs et variétés de modules de complexesI give a way to construct moduli spaces of complexes, as quotients of open subsets of the space of all complexes by the product of the groups of automorphisms of the terms.J. -M. Drezet·Jan 9, 1997SaveLearn
Simultaneous minimal model of homogeneous toric deformationFor a flat family of Du Val singularities, we can take a simultaneous resolution after finite base change. It is an interesting problem to consider this analogy for a flat family of higher…D. Matsushita·Jan 9, 1997SaveLearn
Hodge numbers attached to a polynomial mapGiven a polynomial map f: Cn+1 C, one can attach to it a geometrical variation of mixed Hodge structures (MHS) which gives rise to a limit MHS. The equivariant Hodge numbers of this…Ricardo Garcia, Andras Nemethi·Jan 8, 1997SaveLearn
A smooth surface in P4 not of general type has degree at most 46This is the continuation of papers by Braun and Floystad, Cook, Braun and Cook. We use Generic Initial Ideal Theory in conjunction with Liaison Theory to further restrict the possible generic initial…M. Cook·Jan 4, 1997SaveLearn
A smooth surface in P4 not of general type has degree at most 66We continue the work of Braun and Floystad, and Cook bounding the degree of smooth surfaces in P4 not of general type using generic initial ideal theory.R. Braun, M. Cook·Jan 4, 1997SaveLearn
Jacobi forms and the structure of Donaldson invariants for 4-manifolds with b+=1We prove structure theorems for the Donaldson invariants of 4-manifolds with b+=1, similar to those of Kronheimer and Mrowka in the case b+>1: We show that for a 4-manifold with b+=1 and two…Lothar Göttsche, Don Zagier·Dec 26, 1996SaveLearn
Is a linear space contained in a variety? - On the number of derivatives needed to tellLet Xn⊂ Cn+a or Xn⊂ Pn+a be a patch of an analytic submanifold of an affine or projective space, let x∈ X be a general point, and let Lk be a linear space of dimension k…J. M. Landsberg·Dec 24, 1996SaveLearn
Effective base point freeness on a normal surfaceThis treats the base-point-freeness of the adjoint bundles on normal surfaces with a boundary. This is an extension of the non-relative version of the theorem of Ein-Lazarsfeld-Masek and the theorem…Takeshi Kawachi·Dec 20, 1996SaveLearn
Weil classes on abelian varietiesConsider a complex abelian variety X on which a field F acts. Generalizing a construction of A. Weil, one associates to this a subspace WF of the cohomology of X, which we call the space of Weil…B. J. J. Moonen, Yu. G. Zarhin·Dec 19, 1996SaveLearn