Niveau: Supérieur, Doctorat, Bac+8
ON FANO FOLIATIONS CAROLINA ARAUJO AND STEPHANE DRUEL Abstract. In this paper we address Fano foliations on complex projective varieties. These are foliations F whose anti-canonical class ?KF is ample. We focus our attention on a special class of Fano foliations, namely del Pezzo foliations on complex projective manifolds. We show that these foliations are algebraically integrable, with one exceptional case when the ambient space is Pn. We also provide a classification of del Pezzo foliations with mild singularities. Contents 1. Introduction 1 2. Foliations and Pfaff fields 3 3. Algebraically integrable foliations 5 4. Examples 8 5. The relative anticanonical bundle of a fibration and applications 10 6. Foliations and rational curves 13 7. Algebraic integrability of del Pezzo foliations 18 8. On del Pezzo foliations with mild singularities 27 9. Del Pezzo foliations on projective space bundles 29 References 36 1. Introduction In the last few decades, much progress has been made in the classification of complex projective varieties. The general viewpoint is that complex projective manifoldsX should be classified according to the behavior of their canonical class KX . As a result of the minimal model program, we know that every complex projective manifold can be build up from 3 classes of (possibly singular) projective varieties, namely, varieties X for which KX is Q-Cartier, and satisfies KX < 0, KX ? 0 or KX > 0.
- open neighborhood
- then either
- index ?f
- normal variety
- normal complex projective
- anti- canonical class
- cycle over
- zariski dense
- projective manifold