Hostname: page-component-586b7cd67f-2brh9 Total loading time: 0 Render date: 2024-11-24T23:35:40.264Z Has data issue: false hasContentIssue false

On the structure of 4-folds with a hyperplane section which is a P1 bundle over a surface that fibres over a curve

Published online by Cambridge University Press:  22 January 2016

Maria Lucia Fania
Affiliation:
Istituto di Matematica Università dell’ Aquila, Via Roma 33 67100 L’Aquila, Italia
Eiichi Sato
Affiliation:
Department of Mathematics College of General Education Kyushu University, Kyushu, 810, Japan
Andrew John Sommese
Affiliation:
Department of Mathematics University of Notre Dame, Notre Dame, Indiana 46556, U. S. A.
Rights & Permissions [Opens in a new window]

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

In this article we want to analyze the structure of a 4 dimensional projective variety X which has a smooth ample divisor A that is a P1 bundle π : A→S over a smooth surface S.

In [Fa+So], as a consequence of a more general result, the first and third authors determined the structure of X in the case the base S of the P1 bundle A has a cover with h2,0()≠0. Here we look at the remaining cases except for those surfaces which are the projectivization of a stable rank two vector bundle over a curve (the result is obviously true for S rational).

Type
Research Article
Copyright
Copyright © Editorial Board of Nagoya Mathematical Journal 1987

References

[Bal] Bădescu, L., On ample divisors, Nagoya Math. J., 86 (1982), 155171.CrossRefGoogle Scholar
[Ba2] Bădescu, L., On ample divisors II, Proceedings of the “Week of Algebraic Geometry”, Bucarest 1980, Teubner, Leipzig 1981, 1232.Google Scholar
[Ba3] Bădescu, L., The projective plane blown up at one point as an ample divisor, Atti Accad. Ligure Sci. Lett., 38 (1982), 8892.Google Scholar
[Fa + So] Fania, M. L., Sommese, A. J., Varieties whose hyperplane sections are Pc bundles, preprint.Google Scholar
[Fu] Fujita, T., On the hyperplane section principle of Lefschetz, J. Math. Soc. Japan, 32 (1980), 153169.CrossRefGoogle Scholar
[Hi] Hironaka, H., Smoothing of algebraic cycles of small dimensions, Amer. J. Math., 90 (1968), 4151.CrossRefGoogle Scholar
[Ok + Sc + Sp] Okonek, C. Schneider, M., Spindler, H., Vector bundles on Complex Projective Spaces, Progress in Math. (1980) Birkhäuser, Boston-Basel-Stuttgart.Google Scholar
[Sa] Sato, E., Varieties which have two projective spaces bundle structures, J. Math. Kyoto Univ., 253 (1985), 445457.Google Scholar
[Sol] Sommese, A. J., On manifolds that cannot be ample divisors, Math. Ann., 221 (1976), 5572.CrossRefGoogle Scholar
[So2] Sommese, A. J., On the minimality of hyperplane sections of projective 3-folds, J. reine angew. Math., 3.29 (1981), 1641.Google Scholar