Displaying similar documents to “On the structure of linked 3-folds.”

Geometric genera for ample vector bundles with regular sections.

Antonio Lanteri (2000)

Revista Matemática Complutense

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Let X be a smooth complex projective variety of dimension n ≥ 3. A notion of geometric genus p(X,E) for ample vector bundles E of rank r < n on X admitting some regular sections is introduced. The following inequality holds: p(X,E) ≥ h(X). The question of characterizing equality is discussed and the answer is given for E decomposable of corank 2. Some conjectures suggested by the result are formulated.

Contractions of smooth varieties. II. Computations and applications

Marco Andreatta, Jarosław A. Wiśniewski (1998)

Bollettino dell'Unione Matematica Italiana

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Una contrazione su una varietà proiettiva liscia X è data da una mappa φ : X → Z propria, suriettiva e a fibre connesse in una varietà irriducibile normale Z . La contrazione si dice di Fano-Mori se inoltre - K X è φ -ampio. Nel lavoro, naturale seguito e completamento delle ricerche introdotte in [A-W3], si studiano diversi aspetti delle contrazioni di Fano-Mori attraverso esempi (capitolo 1) e teoremi di struttura (capitoli 3 e 4). Si discutono anche alcune applicazioni allo studio di morfismi birazionali...

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),...

On generation of jets for vector bundles.

Mauro C. Beltrametti, Sandra Di Rocco, Andrew J. Sommese (1999)

Revista Matemática Complutense

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We introduce and study the k-jet ampleness and the k-jet spannedness for a vector bundle, E, on a projective manifold. We obtain different characterizations of projective space in terms of such positivity properties for E. We compare the 1-jet ampleness with different notions of very ampleness in the literature.