Zero-dimensional subschemes of ruled varieties

Edoardo Ballico; Cristiano Bocci; Claudio Fontanari

Displaying similar documents to “Zero-dimensional subschemes of ruled varieties”

Quartic del Pezzo surfaces over function fields of curves

Brendan Hassett, Yuri Tschinkel (2014)

Open Mathematics

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We classify quartic del Pezzo surface fibrations over the projective line via numerical invariants, giving explicit examples for small values of the invariants. For generic such fibrations, we describe explicitly the geometry of spaces of sections to the fibration, and mappings to the intermediate Jacobian of the total space. We exhibit examples where these are birational, which has applications to arithmetic questions, especially over finite fields.

Rational curves on homogeneous cones.

Perrin, Nicolas (2004)

Documenta Mathematica

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Threefolds with big and nef anticanonical bundles II

Priska Jahnke, Thomas Peternell, Ivo Radloff (2011)

Open Mathematics

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In a follow-up to our paper [Threefolds with big and nef anticanonical bundles I, Math. Ann., 2005, 333(3), 569–631], we classify smooth complex projective threefolds Xwith −K X big and nef but not ample, Picard number γ(X) = 2, and whose anticanonical map is small. We assume also that the Mori contraction of X and of its flop X + are not both birational.

Seshadri positive submanifolds of polarized manifolds

Lucian Bădescu, Mauro Beltrametti (2013)

Open Mathematics

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Let Y be a submanifold of dimension y of a polarized complex manifold (X, A) of dimension k ≥ 2, with 1 ≤ y ≤ k−1. We define and study two positivity conditions on Y in (X, A), called Seshadri A-bigness and (a stronger one) Seshadri A-ampleness. In this way we get a natural generalization of the theory initiated by Paoletti in [Paoletti R., Seshadri positive curves in a smooth projective 3-fold, Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl., 1996, 6(4),...

Rationally connected varieties over local fields.

Kollár, János (1999)

Annals of Mathematics. Second Series

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Notes on the arithmetic of Fano threefolds

Yu I. Manin (1993)

Compositio Mathematica

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On threefolds admitting a bielliptic curve as abstract complete intersection.

Del Centina, A., Gimigliano, A. (2001)

Advances in Geometry

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A series of smooth irregular varieties in projective space

Ciro Ciliberto, Klaus Hulek (1999)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

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Varieties with $P_{3} (X) = 4$ and $q (X) =$ dim $(X)$

Jungkai Alfred Chen, Christopher D. Hacon (2004)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

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Equivalence of families of singular schemes on threefolds and on ruled fourfolds.

Flaminio Flamini (2004)

Collectanea Mathematica

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The main purpose of this paper is twofold. We first analyze in detail the meaningful geometric aspect of the method introduced in [12], concerning families of irreducible, nodal curves on a smooth, projective threefold X. This analysis gives some geometric interpretations not investigated in [12] and highlights several interesting connections with families of other singular geometric objects related to X and to other varieties. Then we use this method to study analogous problems for...