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On the canonical degrees of curves in varieties of general type
Pascal Autissier 1, Antoine Chambert-Loir 2, Carlo Gasbarri 3
(19/03/2010)

A widely believed conjecture predicts that curves of bounded geometric genus lying on a variety of general type form a bounded family. One may even ask whether the canonical degree of a curve $C$ in a variety of general type is bounded from above by some expression $a\chi(C)+b$, where $a$ and $b$ are positive constants, with the possible exceptions corresponding to curves lying in a strict closed subset (depending on $a$ and $b$). A theorem of Miyaoka proves this for smooth curves in minimal surfaces, with $a>3/2$. A conjecture of Vojta claims in essence that any constant $a>1$ is possible provided one restricts oneself to curves of bounded gonality. We show by explicit examples that in general, the constant $a$ has to be at least equal to the dimension of the ambient variety.
1 :  Institut de Mathématiques de Bordeaux (IMB)
CNRS : UMR5251 – Université Sciences et Technologies - Bordeaux I – Université Victor Segalen - Bordeaux II
2 :  Institut de Recherche Mathématique de Rennes (IRMAR)
CNRS : UMR6625 – Université de Rennes 1 – École normale supérieure de Cachan - ENS Cachan – Institut National des Sciences Appliquées (INSA) : - RENNES – Université de Rennes II - Haute Bretagne
3 :  Institut de Recherche Mathématique Avancée (IRMA)
CNRS : UMR7501 – Université de Strasbourg
Mathématiques/Géométrie algébrique
Lien vers le texte intégral : 
http://fr.arXiv.org/abs/1003.3804