Algebraic geometry/Analytic geometry
The direct image of the relative dualizing sheaf needs not be semiample
[L'image directe du faisceau dualisant relatif n'est pas nécessairement semi-ample]
Comptes Rendus. Mathématique, Tome 352 (2014) no. 3, pp. 241-244.

Nous donnons des détails sur la démonstration du second théorème de Fujita et nous montrons que l'image directe du fibré canonique relatif V:=fωX/B d'une fibration f:XB sur une courbe B est la somme directe d'un fibré vectoriel ample et d'un fibré vectoriel unitairement plat si l'espace total X est une variété kählérienne compacte. Nous montrons en outre que V n'est en général pas semi-ample, ce qui constitue notre résultat principal.

We provide details for the proof of Fujita's second theorem and prove that for a Kähler fibre space f:XB over a smooth projective curve B, the direct image of the relative dualizing sheaf V:=fωX/B is the direct sum of an ample and a unitary flat bundle. We also show that V needs not be semiample, which is our main result.

Reçu le :
Accepté le :
Publié le :
DOI : 10.1016/j.crma.2013.12.015
Catanese, Fabrizio 1 ; Dettweiler, Michael 1

1 Mathematisches Institut, Universität Bayreuth, 95447 Bayreuth, Germany
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Catanese, Fabrizio; Dettweiler, Michael. The direct image of the relative dualizing sheaf needs not be semiample. Comptes Rendus. Mathématique, Tome 352 (2014) no. 3, pp. 241-244. doi : 10.1016/j.crma.2013.12.015. http://www.numdam.org/articles/10.1016/j.crma.2013.12.015/

[1] Catanese, F.; Dettweiler, M. Answer to a question by Fujita on variation of Hodge structures, 2013 (preprint, 26 pages) | arXiv

[2] Deligne, P.; Mostow, G.D. Monodromy of hypergeometric functions and non-lattice integral monodromy, Publ. Math. IHÉS, Volume 63 (1986), pp. 5-89

[3] Fujita, Takao On Kähler fiber spaces over curves, J. Math. Soc. Jpn., Volume 30 (1978) no. 4, pp. 779-794

[4] Fujita, Takao The sheaf of relative canonical forms of a Kähler fiber space over a curve, Proc. Jpn. Acad., Ser. A, Math. Sci., Volume 54 (1978) no. 7, pp. 183-184

[5] Griffiths, P. Periods of integrals on algebraic manifolds. III. Some global differential-geometric properties of the period mapping, Publ. Math. IHÉS, Volume 38 (1970), pp. 125-180

[6] Griffiths, P. Topics in Transcendental Algebraic Geometry, Annals of Mathematics Studies, vol. 106, Princeton University Press, 1984

[7] Griffiths, P.; Harris, J. Principles of Algebraic Geometry, Pure and Applied Mathematics, Wiley-Interscience, New York, 1978

[8] Griffiths, P.; Schmid, W. Recent developments in Hodge theory: A discussion of techniques and results, 1973 (1975), pp. 31-127

[9] Hartshorne, R. Ample vector bundles on curves, Nagoya Math. J., Volume 43 (1971), pp. 73-89

[10] Classification of algebraic and analytic manifolds, Proc. Symp. Katata/Jap. (Ueno, Kenji, ed.) (Progress in Mathematics), Volume vol. 39, Birkhäuser, Boston, Mass. (1983), pp. 591-630 (Open problems: Classification of algebraic and analytic manifolds, 1982)

[11] Kawamata, Y. Kodaira dimension of algebraic fiber spaces over curves, Invent. Math., Volume 66 (1982) no. 1, pp. 57-71

[12] Kempf, G.; Knudsen, F.F.; Mumford, D.; Saint Donat, B. Toroidal Embeddings, I, Lecture Notes in Mathematics, vol. 739, Springer, 1973 (viii+209 p)

[13] Kohno, M. Global Analysis in Linear Differential Equations, Kluwer Academic Publishers, 1999

[14] Kollár, J. Higher direct images of dualizing sheaves. I, II, Ann. Math. (2), Volume 123 (1986), pp. 11-42

[15] Lazarsfeld, R. Positivity in algebraic geometry. II. Positivity for vector bundles, and multiplier ideals, Ergebnisse der Mathematik und ihrer Grenzgebiete. 3, vol. 49, Springer-Verlag, Berlin, 2004 (xviii+385 p)

[16] Peters, C.A.M. A criterion for flatness of Hodge bundles over curves and geometric applications, Math. Ann., Volume 268 (1984) no. 1, pp. 1-19

[17] Schmid, W. Variation of Hodge structure: The singularities of the period mapping, Invent. Math., Volume 22 (1973), pp. 211-319

[18] Schwarz, H.A. Über diejenigen Fälle in welchen die Gaussische hypergeometrische Reihe eine algebraische Funktion ihres vierten Elements darstellt, J. Reine Angew. Math., Volume 75 (1873), pp. 292-335

[19] Zucker, S. Hodge theory with degenerating coefficients: L2-cohomology in the Poincaré metric, Ann. Math. (2), Volume 109 (1979), pp. 415-476

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