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Hilbert schemes and stable pairs: GIT and derived category wall crossings

Jacopo Stoppa, Richard P. Thomas (2011)

Bulletin de la Société Mathématique de France

We show that the Hilbert scheme of curves and Le Potier’s moduli space of stable pairs with one dimensional support have a common GIT construction. The two spaces correspond to chambers on either side of a wall in the space of GIT linearisations. We explain why this is not enough to prove the “DT/PT wall crossing conjecture” relating the invariants derived from these moduli spaces when the underlying variety is a 3-fold. We then give a gentle introduction to a small part of Joyce’s theory for such...

Hodge metrics and the curvature of higher direct images

Christophe Mourougane, Shigeharu Takayama (2008)

Annales scientifiques de l'École Normale Supérieure

Using the harmonic theory developed by Takegoshi for representation of relative cohomology and the framework of computation of curvature of direct image bundles by Berndtsson, we prove that the higher direct images by a smooth morphism of the relative canonical bundle twisted by a semi-positive vector bundle are locally free and semi-positively curved, when endowed with a suitable Hodge type metric.

Hodge numbers attached to a polynomial map

R. García López, A. Némethi (1999)

Annales de l'institut Fourier

We attach a limit mixed Hodge structure to any polynomial map f : ℂ n → ℂ . The equivariant Hodge numbers of this mixed Hodge structure are invariants of f which reflect its asymptotic behaviour. We compute them for a generic class of polynomials in terms of equivariant Hodge numbers attached to isolated hypersurface singularities and equivariant Hodge numbers of cyclic coverings of projective space branched along a hypersurface. We show how these invariants allow to determine topological invariants of f such...

Hodge-gaussian maps

Elisabetta Colombo, Gian Pietro Pirola, Alfonso Tortora (2001)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

Hodge–type structures as link invariants

Maciej Borodzik, András Némethi (2013)

Annales de l’institut Fourier

Based on some analogies with the Hodge theory of isolated hypersurface singularities, we define Hodge–type numerical invariants of any, not necessarily algebraic, link in a three–sphere. We call them H–numbers. They contain the same amount of information as the (non degenerate part of the) real Seifert matrix. We study their basic properties, and we express the Tristram–Levine signatures and the higher order Alexander polynomial in terms of them. Motivated by singularity theory, we also introduce...

Holomorphic rank-2 vector bundles on non-Kähler elliptic surfaces

Vasile Brînzănescu, Ruxandra Moraru (2005)

Annales de l’institut Fourier

In this paper, we consider the problem of determining which topological complex rank-2 vector bundles on non-Kähler elliptic surfaces admit holomorphic structures; in particular, we give necessary and sufficient conditions for the existence of holomorphic rank-2 vector bundles on non-{Kä}hler elliptic surfaces.

Hurwitz spaces of genus 2 covers of an elliptic curve.

Ernst Kani (2003)

Collectanea Mathematica

Let E be an elliptic curve over a field K of characteristic not equal to 2 and let N > 1 be an integer prime to char(K). The purpose of this paper is to construct the (two-dimensional) Hurwitz moduli space H (E/K,N,2) which classifies genus 2 covers of E of degree N and to show that it is closely related to the modular curve X(N) which parametrizes elliptic curves with level-N-structure. More precisely, we introduce the notion of a normalized genus 2 cover of E/K and show that the corresponding...

Images directes I : Espaces rigides analytiques et images directes

Jean-Yves Etesse (2012)

Journal de Théorie des Nombres de Bordeaux

Cet article est le premier d’une série de trois articles consacrés aux images directes d’isocristaux : ici nous considérons des isocristaux sans structure de Frobenius ; dans le deuxième [Et 6] (resp. le troisième [Et 7]), nous introduirons une structure de Frobenius dans le contexte convergent (resp. surconvergent).Pour un morphisme propre et lisse relevable nous établissons la surconvergence des images directes, grâce à un théorème de changement de base pour un morphisme propre entre espaces rigides...

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