H. L. M. (Hrushovski-Lang-Mordell)
Half-twists and equations in genus 2.
Halphen gaps and good space curves
In questo articolo dimostriamo l'esistenza di curve "buone e generali" di grado e genere che giacciono su di una superfice liscia di grado , per ogni , , e in un certo intervallo vicino al genere massimo.
Halphen pencils on weighted Fano threefold hypersurfaces
On a general quasismooth well-formed weighted hypersurface of degree Σi=14 a i in ℙ(1, a 1, a 2, a 3, a 4), we classify all pencils whose general members are surfaces of Kodaira dimension zero.
Halphen's gaps for space curves of submaximum genus
Halves of a real Enriques surface.
Hamburger-Noether Expansions and Approximate Roots of Polynomials.
Hamiltonian stability and subanalytic geometry
In the 70’s, Nekhorochev proved that for an analytic nearly integrable Hamiltonian system, the action variables of the unperturbed Hamiltonian remain nearly constant over an exponentially long time with respect to the size of the perturbation, provided that the unperturbed Hamiltonian satisfies some generic transversality condition known as steepness. Using theorems of real subanalytic geometry, we derive a geometric criterion for steepness: a numerical function which is real analytic around a...
Harder-Narasimhan filtrations and optimal destabilizing vectors in complex geometry
We give here a generalization of the theory of optimal destabilizing 1-parameter subgroups to non algebraic complex geometry : we consider holomorphic actions of a complex reductive Lie group on a finite dimensional (possibly non compact) Kähler manifold. In a second part we show how these results may extend in the gauge theoretical framework and we discuss the relation between the Harder-Narasimhan filtration and the optimal detstabilizing vectors of a non semistable object....
Hardy fields in several variables
In questo lavoro si estende il concetto di campo di Hardy [Bou], al contesto dei germi di funzioni in più variabili che sono definite su insiemi semi-algebrici [Br.], [D.] e che risultano essere morfismi di categorie lisce [Pal.]. In tale contesto si dimostra che per ogni campo di Hardy di germi di una fissata categoria liscia , la sua chiusura algebrica relativa nell'anello , di tutti i germi nella stessa categoria liscia, è un campo di Hardy reale chiuso, che è l'unica chiusura reale del campo...
Hardy-Littlewood varieties and semisimple groups.
Harish-Chandra homomorphisms and symplectic reflection algebras for wreath-products
The main result of the paper is a natural construction of the spherical subalgebra in a symplectic reflection algebra associated with a wreath-product in terms of quantum hamiltonian reduction of an algebra of differential operators on a representation space of an extended Dynkin quiver. The existence of such a construction has been conjectured in [EG]. We also present a new approach to reflection functors and shift functors for generalized preprojective algebras and symplectic reflection algebras...
Harmonic gauges on Riemann surfaces and stable bundles
Hasse principle and weak approximation for pencils of Severi-Brauer and similar varieties.
Hasse's principle for simple algebras over function fields of curves. I. Algebras of index 2 and 3; curves of genus 0 and 1.
Hasse-Witt matrices and Kummer extension
A simple calculation of the Hasse-Witt matrix is used to give examples of curves which are Kummer coverings of the projective line and which have easily determined p-rank. A family of curve carrying non-classical vector bundles of rank 2 is also given.
Hasse-Witt Matrices of Fermat curves.
Hasse-Witt-Invariants and Dihedral Extension.
Hauteur des correspondances de Hecke
L’objectif de cet article est de mesurer la complexité arithmétique de la courbe modulaire en fonction du niveau . Pour ce faire, on utilise un morphisme fini (de degré 1 sur son image) de vers une variété fixe et on calcule la hauteur au sens d’Arakelov de l’image de ce morphisme. La hauteur employée est directement reliée à la hauteur de Faltings des courbes elliptiques. On a besoin pour cela de considérer une théorie d’Arakelov pour les faisceaux inversibles hermitiens -singuliers (au...
Hauteurs canoniques sur l'espace de modules des fibrés stables sur une courbe algébrique