Summary
In this article we exhibit certain projective degenerations of smoothK3 surfaces of degree 2g−2 in ℙg (whose Picard group is generated by the hyperplane class), to a union of two rational normal scrolls, and also to a union of planes. As a consequence we prove that the general hyperplane section of suchK3 surfaces has a corank one Gaussian map, ifg=11 org≥13. We also prove that the general such hyperplane section lies on a uniqueK3 surface, up to projectivities. Finally we present a new approach to the classification of prime Fano threefolds of index one, which does not rely on the existence of a line.
Similar content being viewed by others
References
Bayer D., Eisenbud, D.: Graph Curves (preprint)
Bertram, A., Ein, L., Lazarsfeld, R.: Surjectivity of Gaussian Maps for Line Bundles of Large Degree on Curves (preprint)
Beauville A., Merindol, J.-Y.: Sectiones Hyperplanes des SurfacesK3. Duke Math. J.55, 873–878 (1987)
The Birational Geometry of Degenerations edited by R., Friedman and D. Morrison. Progr. Math. vol. 29, Basel, Boston: Birkhäuser 1983
Ciliberto C., Franchetta, A.: Curve poligonali, grafi e applicazione di Gauss. Rendiconti di Matematica12, 165–196 (1992)
Ciliberto C., Franchetta, A.: L'applicazione di Gauss per grafi trivalenti (preprint)
Ciliberto, C., Harris, J., Miranda, R.: On the surjectivity of the Wahl map. Duke Math. J.57, 829–858 (1988)
Ciliberto, C., Miranda, R.: On the Gaussian map for canonical curves of low genus. Duke Math.J. 61, 417–443 (1990)
Ciliberto, C., Miranda, R.: Graph Curves, Colorings, and Matroids. Proceedings of the Ravello Conference on Zero-Dimensional Schemes, Ravello, Italy, June 1992 (to appear)
Cukierman, F., Ulmer, D.: Curves of Genus Ten onK3 Surfaces. Compositio Math. (to appear)
Friedman, R.: Global Smoothings of Varieties with Normal Crossings. Ann. Math. Vol.118, 75–114 (1983)
Griffiths, P., Harris, J.: On the Noether-Lefschetz Theorem and Some Remarks on Codimension-two Cycles. Math. Ann.271, 31–51 (1985)
Iskovskih, V.A.: Fano Threefolds II. Math. USSR Izvestija12, 469–506 (1978)
Kleppe, J.: The Hilbert Flag Scheme, its properties, and its connection with the Hilbert Scheme. Applications to curves in three-space. Thesis, University of Oslo, Preprint No. 5 (1981)
Kleppe, J.: Non-reduced components of the Hilbert scheme of smooth space curves. In: Space Curve, Rocca di papa, 1985, Ghione, F., Peskine, C., Sernesi, E. (eds.) Springer Lect. Notes Math. No. 1266 (1987), 181–207
Kodaira, K.: On compact analytic surfaces II, III. Ann. Math.77, 563–626 (1963);78, 1–40 (1963)
Kulikov, V.: Degenerations ofK3 surfaces and Enriques Surfaces. Math. USSR Izvestija11, 957–989 (1977)
L'vovsky, S.M.: On the extension of varieties defined by quadratic equations. Math. USSR Sbornik63, 305–317 (1989)
Miranda, R.: The Gaussian map for certain planar graph curves. In: Algebraic Geometry: Sundance 1988. B. Harbourne and R. Speiser, editors. Contemp. Math.116, 115–124 (1991)
Moishezon, B.: On algebraic cohomology classes on algebraic varieties. Izv. Akad. Nauk USSR, Ser. Math31, 225–268 (1967)
Mori, S., Mukai, S.: The uniruledness of the moduli space of curves of genus 11. In: Algebraic Geometry, Proceedings, Tokyo/Kyoto (1982), Springer Lect. Notes Math. 1016 (1983), 334–353
Mukai, S.: Fano 3-folds. In:Complex Projective Geometry, Ellingsrud, G., Peskine, C., Sacchiero, G., Stromme, S.A. (eds.) London Mathematical Society, Lecture Note Series No.179, 255–263 (1992)
Voisin, C.: Sur l'application de Wahl des courbes satisfaisant la condition de Brill-Noether-Petri (preprint)
Wahl, J.: The Jacobian Algebra of a graded Gorenstein singularity. Duke Math. J.55, 843–871 (1987)
Author information
Authors and Affiliations
Additional information
Oblatum 1-II-1993 & 24-V-1993
Research supported in part by NSF grant DMS-9104058
Rights and permissions
About this article
Cite this article
Ciliberto, C., Lopez, A. & Miranda, R. Projective degenerations of K3 surfaces, Gaussian maps, and Fano threefolds. Invent Math 114, 641–667 (1993). https://doi.org/10.1007/BF01232682
Issue Date:
DOI: https://doi.org/10.1007/BF01232682