Abstract
We study the behavior of theta characteristics on an algebraic curve under the specialization map to a tropical curve. We show that each effective theta characteristic on the tropical curve is the specialization of \(2^{g-1}\) even theta characteristics and \(2^{g-1}\) odd theta characteristics. We then study the relationship between unramified double covers of a tropical curve and its theta characteristics, and use this to define the tropical Prym variety.
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Amini, O., Baker, M.: Linear series on metrized complexes of algebraic curves. Math. Ann. 362(1–2), 55–106 (2015)
Amini, O., Baker, M., Brugallé, E., Rabinoff, J.: Lifting harmonic morphisms I: metrized complexes and Berkovich skeleta. Res. Math. Sci., 2, Art. 7, 67 (2015)
Alexeev, V., Birkenhake, C., Hulek, K.: Degenerations of Prym varieties. J. Reine Angew. Math. 553, 73–116 (2002)
Arbarello, E., Cornalba, M., Griffiths, P.A., Harris, J.: Geometry of Algebraic Curves. Vol. I, Volume 267 of Grundlehren der Mathematischen Wissenschaften. Springer, New York (1985)
Baker, M.: Specialization of linear systems from curves to graphs. Algebra Number Theory 2(6), 613–653 (2008)
Baker, M., Faber, X.: Metric properties of the tropical Abel–Jacobi map. J. Algebr. Combin. 33(3), 349–381 (2011)
Baker, M., Len, Y., Morrison, R., Pflueger, N., Ren, Q.: Bitangents of tropical plane quartic curves. Math. Z. 282(3–4), 1017–1031 (2016)
Baker, M., Norine, S.: Riemann–Roch and Abel–Jacobi theory on a finite graph. Adv. Math. 215(2), 766–788 (2007)
Baker, M., Rabinoff, J.: The skeleton of the Jacobian, the Jacobian of the skeleton, and lifting meromorphic functions from tropical to algebraic curves. Int. Math. Res. Not. 2015(16), 7436–7472 (2015)
Chan, M., Jiradilok, P.: Theta characteristics of tropical \(k_4\)-curves. preprint arXiv:1503.05776 (2015)
Cavalieri, R., Markwig, H., Ranganathan, D.: Tropicalizing the space of admissible covers. Math. Ann. 364(3–4), 1275–1313 (2016)
Harris, J.: Theta-characteristics on algebraic curves. Trans. Am. Math. Soc. 271, 611–638 (1982)
Harris, C., Len, Y.: Tritangent planes to space sextics: the algebraic and tropical stories. In: Smith, G.G., Sturmfels, B. (eds.) Combinatorial algebraic geometry: selected papers from the 2016 apprenticeship program, pp. 47–63. Springer, New York (2017)
Len, Y., Markwig, H.: Lifting tropical bitngents. preprint arXiv:1708.04480 (2017)
Mikhalkin, G., Zharkov, I.: Tropical curves, their Jacobians and theta functions. In: Donagi, R. (ed.) Curves and Abelian Varieties, Volume 465 of Contemporary Mathematics, pp. 203–230. American Mathematical Society, Providence (2008)
Panizzut, M.: Theta characteristics of hyperelliptic graphs. preprint arXiv:1511.07243 (2015)
Viviani, F.: Tropicalizing vs. compactifying the Torelli morphism. In: Amini, O., Baker, M., Faber, X. (eds.) Tropical and Non-Archimedean Geometry, Volume 605 of Contemporary Mathematics, pp. 181–210. American Mathematical Society, Providence (2013)
Waller, Derek A.: Double covers of graphs. Bull. Aust. Math. Soc. 14(2), 233–248 (1976)
Zharkov, I.: Tropical theta characteristics. In: Gross, M. (ed.) Mirror Symmetry and Tropical Geometry, Volume 527 of Contemporary Mathematics, pp. 165–168. American Mathematical Society, Providence (2010)
Acknowledgements
The bulk of this paper was written during a Research in Pairs stay at Oberwolfach. We would like to thank the institute for providing ideal working conditions for exploring these ideas. The first author’s travel was supported by an AMS Simons travel grant, and the second author was partially support by DFG Grant MA 4797/6-1. We are grateful to Matt Baker for insightful remarks on a previous version of this manuscript, and thank Sam Payne, Joe Rabinoff, Dhruv Ranganathan, and Farbod Shokrieh for fielding our questions. Finally, we thank the referees for their insightful remarks.
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Jensen, D., Len, Y. Tropicalization of theta characteristics, double covers, and Prym varieties. Sel. Math. New Ser. 24, 1391–1410 (2018). https://doi.org/10.1007/s00029-017-0379-6
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DOI: https://doi.org/10.1007/s00029-017-0379-6