Under some positivity assumptions, estension properties of rationally connected fibrations from a submanifold to its ambient variety are studied. Given a family of rational curves on a complex projective manifolds X inducing a covering family on a submanifold Y with ample normal bundle in X, the main results relate, under suitable conditions, the associated rational connected fiber structures on X and on Y. Applications of these results include an extension theorem for Mori contractions of fiber type and a classification theorem in the case Y has a structure of projective bundle or quadric fibration.
|Titolo:||Ample subvarieties and rationally connected fibrations|
|Autori interni:||LANTERI, ANTONIO (Ultimo)|
|Parole Chiave:||Ample subvariety ; rationally connected fibration ; family of rational curves ; special varieties ; extension of maps ; Mori contraction|
|Settore Scientifico Disciplinare:||Settore MAT/03 - Geometria|
|Data di pubblicazione:||ago-2008|
|Digital Object Identifier (DOI):||10.1007/s00208-008-0217-4|
|Appare nelle tipologie:||01 - Articolo su periodico|