Abstract
We give refined statements and modern proofs of Rosenlicht’s results about the canonical model C′ of an arbitrary complete integral curve C. Notably, we prove that C and C′ are birationally equivalent if and only if C is nonhyperelliptic, and that, if C is nonhyperelliptic, then C′ is equal to the blowup of C with respect to the canonical sheaf ω. We also prove some new results: we determine just when C′ is rational normal, arithmetically normal, projectively normal, and linearly normal.
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Arbarello E., Cornalba M., Griffiths P.A., Harris J.: Geometry of Algebraic Curves. Springer- Verlag, Berlin (1985)
Bertini E.: Introduzione alla Geometria Proiettiva degli Iperspazi. Enrico Spoerri, Pisa (1907)
Barucci V., Fröberg R.: One-dimensional almost Gorenstein rings. J. Alg 188, 418–442 (1997)
Catanese, F., Pluricanonical-Gorenstein-curves, In Enumerative geometry and classical algebraic geometry (Nice, 1981), Progr. Math., 24, Birkhäuser Boston, 1982, pp. 51–95
Eisenbud D.: Linear sections of determinantal varieties. Am. J. Math. 110(3), 541–575 (1988)
Eisenbud, D.: Commutative algebra with a view towards algebraic geometry. Graduate Texts in Mathematics 150. Springer, New York (1994)
Eisenbud, D., Koh, J., Stillman, M. (appendix with Harris, J.): Determinantal equations for curves of high degree. Am. J. Math. 110, 513–539 (1988)
Fujita, T.: Defining equations for certain types of polarized varieties. In Complex Analysis and Algebraic Geometry, pp. 165–173. Iwanami Shoten, Tokyo (1977)
Fujita T.: On hyperelliptic polarized varieties. Thoku Math. J. 35(2), 1–44 (1983)
Grothendieck, A., and Dieudonné, J.: Éléments de géométrie algébrique. II. Étude globale élémentaire de quelques classes de morphismes. Inst. Hautes Études Sci. Publ. Math. vol. 8 (1961)
Hartshorne R.: Algebraic Geometry. Springer-Verlag, New York (1977)
Homma M.: Singular hyperelliptic curves. Manuscr. Math. 98, 21–36 (1999)
Hartshorne R.: Generalized divisors on Gorenstein curves and a theorem of Noether. J. Math. Kyoto Univ. 26-3, 375–386 (1986)
Kempf, G.: The singularities of certain varieties in the Jacobian of a curve. PhD thesis, Columbia University (1971)
Kleiman S., Landolfi J.: Geometry and deformation of special Schubert varieties. Compos. Math. 23, 407–434 (1971)
Lipman J.: Stable ideals and Arf rings. Am. J. Math. 93(3), 649–685 (1971)
Martins R.V.: On trigonal non-Gorenstein curves with zero Maroni invariant. J. Algebra 275, 453–470 (2004)
Mumford, D.: Lectures on curves on an algebraic surface. With a section by G.M. Bergman, Annals of Mathematics Studies, No. 59. Princeton University Press, Princeton (1966)
Rosenlicht M.: Equivalence relations on algebraic curves. Ann. Math. 56, 169–191 (1952)
Saint-Donat B.: On Petri’s analysis of the linear system of quadrics through a canonical curve. Math. Ann. 206, 157–175 (1973)
Serre J.P.: Groupes Algébriques et Corps de Classes. Hermann, Paris (1959)
Stöhr K.-O.: On the poles of regular differentials of singular curves. Bull. Braz. Math. Soc. 24, 105–135 (1993)
Stöhr K.-O.: Hyperelliptic Gorenstein curves. J. Pure Appl. Algebra 135, 93–105 (1999)
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Kleiman, S.L., Martins, R.V. The canonical model of a singular curve. Geom Dedicata 139, 139–166 (2009). https://doi.org/10.1007/s10711-008-9331-4
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DOI: https://doi.org/10.1007/s10711-008-9331-4