NEARLY FREE CURVES AND ARRANGEMENTS: A VECTOR BUNDLE POINT OF VIEW - Archive ouverte HAL Accéder directement au contenu
Pré-Publication, Document De Travail Année : 2019

NEARLY FREE CURVES AND ARRANGEMENTS: A VECTOR BUNDLE POINT OF VIEW

Résumé

Many papers are devoted to study logarithmic sheaves associated to reduced divisors , in particular logarithmic bundles associated to plane curves since forty years in differential and algebraic topology or geometry. An interesting family of these curves are the so-called free ones for which the associated logarithmic sheaf is the direct sum of two line bundles. When the curve is a finite set of distinct lines (i.e. a line arrangement), Terao conjectured thirty years ago that its freeness depends only on its combinatorics. A lot of efforts were done to prove it but at this time it is only proved up to 12 lines. If one wants to find a counter example to this conjecture a new family of curves arises naturally: the nearly free curves introduced by Dimca and Sticlaru. We prove here that the logarithmic bundle associated to a nearly free curve possesses a minimal non zero section that vanishes on one single point P , called jumping point, and that characterizes the bundle. Then we give a precise description of the behaviour of P. In particular we show, based on detailed examples, that the position of P relatively to its corresponding nearly free arrangement of lines may or may not be a combinatorial invariant, depending on the chosen combinatorics.
Fichier principal
Vignette du fichier
1712.04867(1).pdf (441.58 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-01991250 , version 1 (23-01-2019)

Identifiants

  • HAL Id : hal-01991250 , version 1

Citer

Simone Marchesi, Jean Vallès. NEARLY FREE CURVES AND ARRANGEMENTS: A VECTOR BUNDLE POINT OF VIEW. 2019. ⟨hal-01991250⟩
57 Consultations
110 Téléchargements

Partager

Gmail Facebook X LinkedIn More