We study a particular class of rationally connected manifolds, X HPN, such that two general points x;x0 A X may be joined by a conic contained in X. We prove that these manifolds are Fano, with b2 e 2. Moreover, a precise classification is obtained for b2 1⁄4 2. Complete intersections of high dimension with respect to their multi-degree provide examples for the case b2 1⁄4 1. The proof of the classification result uses a general characterization of rationality, in terms of suitable covering families of rational curves.

Conic–connected manifolds

RUSSO, Francesco
2010

Abstract

We study a particular class of rationally connected manifolds, X HPN, such that two general points x;x0 A X may be joined by a conic contained in X. We prove that these manifolds are Fano, with b2 e 2. Moreover, a precise classification is obtained for b2 1⁄4 2. Complete intersections of high dimension with respect to their multi-degree provide examples for the case b2 1⁄4 1. The proof of the classification result uses a general characterization of rationality, in terms of suitable covering families of rational curves.
conic-connected manifold; second fundamental form; rational curves
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11769/7877
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