Abstract
We study the gonality of a curve C and its canonical model \(C'\), by means of unicuspidal rational curves, where those concepts can be better understood. We start by a general formula for the dimension of the space of hypersurfaces of a fixed degree containing \(C'\), which we apply to some particular cases. Then we classify unicuspidal rational curves via different notions of gonality, and by its canonical model, up to genus 6. We do it using general methods applied to certain families of curves of arbitrary genus.
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Altman, A.B., Kleiman, S.L.: Compactifying the Jacobian. Bull. Am. Math. Soc. 82(6), 947–949 (1976). https://doi.org/10.1090/S0002-9904-1976-14229-2
Barucci, V., D’Anna, M., Fröberg, R.: Analytically unramified one-dimensional semilocal rings and their value semigroups. J. Pure Appl. Algebra 147(3), 215–254 (2000). https://doi.org/10.1016/S0022-4049(98)00160-1
Behnke, K., Christophersen, J.A.: Hypersurface sections and obstructions (rational surface singularities). Compos. Math. 77(3), 233–268 (1991)
Cotterill, E., Feital, L., Martins, R.V.: Dimension counts for cuspidal rational curves via semigroups. Proc. Am. Math. Soc. 148(8), 3217–3231 (2020). https://doi.org/10.1090/proc/15062
Cotterill, E., Lima, V.L., Martins, R.V.: Severi dimensions for unicuspidal curves. J. Algebra 597(299–331), 0021–8693 (2022). https://doi.org/10.1016/j.jalgebra.2021.11.028
Eisenbud, D., Harris, J.: On varieties of minimal degree (a centennial account). In: Bloch, S.J. (ed.) Algebraic Geometry - Bowdoin, 1985. Proceedings of Symposia on Pure Mathematics, vol. 46, Part 1, pp. 3–13. Amer. Math. Soc. Providence, RI (1987). https://doi.org/10.1090/pspum/046.1/927946
Eisenbud, D., Koh, J., Stillman, M.: Determinantal equations for curves of high degree. Am. J. Math. 110(3), 513–539 (1988). https://doi.org/10.2307/2374621
Feital, L., Martins, R..V.: Gonality of non-Gorenstein curves of genus five. Bull. Braz. Math. Soc. (N.S.) 45(4), 649–670 (2014). https://doi.org/10.1007/s00574-014-0067-5
Gagliardi, E., Martins, R.V.: Max Noether Theorem for singular curves, arXiv:2202.09349
Galdino, N., Martins, R.V., Nicolau, D.: Family of Rational Curves with Two Blocks of Values https://sites.google.com/view/singularintegralcurves/inicio
Kleiman, S.L., Martins, R.V.: The canonical model of a singular curve. Geom. Dedicata. 139139–166, (2009). https://doi.org/10.1007/s10711-008-9331-4
Martins, R.V.: On trigonal non-Gorenstein curves with zero Maroni invariant. J. Algebra 275(2), 453–470 (2004). https://doi.org/10.1016/j.jalgebra.2003.10.033
Martins, R.V., Lara, D., Souza, J.M.: On gonality, scrolls, and canonical models of non-Gorenstein curves. Geom. Dedicata. 203, 111–133 (2019). https://doi.org/10.1007/s10711-019-00428-2
Rosa, R., Stöhr, K.-O.: Trigonal Gorenstein curves. J. Pure Appl. Algebra 174(2), 187–205 (2002). https://doi.org/10.1016/S0022-4049(02)00122-6
Rosenlicht, M.: Equivalence relations on algebraic curves. Ann. Math. (2) 56, 169–191 (1952). https://doi.org/10.2307/1969773
Schreyer, F.-O.: Syzygies of canonical curves and special linear series. Math. Ann. 275(1), 105–137 (1986). https://doi.org/10.1007/BF01458587
Stevens, J.: The versal deformation of universal curve singularities. Abh. Math. Sem. Univ. Hamburg 63(197–213), 0025–5858 (1993). https://doi.org/10.1007/BF02941342
Stöhr, K.-O.: On the poles of regular differentials of singular curves. Bol. Soc. Brasil. Mat. (N.S.) 24(1), 105–136 (1993). https://doi.org/10.1007/BF01231698
Acknowledgements
We thank the referee for many suggestions and corrections we built into this version. This work is part of the first named author’s Ph.D thesis. The second named author is partially supported by FAPEMIG RED-00133-21. We thank C. Carvalho, E. Cotterill, A. Fenandez and M. E. Hernandes for many suggestions as well.
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Communicated by Nathan Kaplan.
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Galdino, N., Martins, R.V. & Nicolau, D. On gonality and canonical models of unicuspidal rational curves. Semigroup Forum 107, 79–108 (2023). https://doi.org/10.1007/s00233-023-10354-1
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DOI: https://doi.org/10.1007/s00233-023-10354-1