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TOL47.pdf (1.02 MB)

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Doctoral thesis

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Published version

Publication date

1998-12-21

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Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/35132

On the Slope and Geography of Fibred Surfaces and Threefolds.

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Abstract

[eng] In this tesis we study numerical propieties of surfaces and threefolds, mainly fibred over curves, the so called "slope" of the fibration. We prove partially a conjecture of Fujita on the semiampleness of the direct image of the relative dualizing sheaf of a fibration. We give new lower bounds of the slope of a fibred surface depending on data of the general fibre (existence of involutions) and on data of the hole surface (the fibration not being the Albanese morphism, for example). We study the case of threefolds over curves. We prove that, in general, the relative algebraic Euler characteristic is nonnegative and give lower bound for the slope. We classify the lowest cases of the invariants.

Subject

Geometria algebraica, Superfícies algebraiques

Subject (English)

Algebraic geometry, Surfaces, Algebraic

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Tesis Doctorals - Departament - Algebra i Geometria

Citation

BARJA YÁÑEZ, Miguel Ángel. On the Slope and Geography of Fibred Surfaces and Threefolds. ISBN 8447526143. [consulted: 11 of June of 2026]. Available at: https://hdl.handle.net/2445/35132

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