Abstract
Motivated by toric geometry, we lift machinery for understanding the syzygies of curves in projective space to the setting of products of projective spaces. Using this machinery, we show an analogue of an influential result of Gruson, Peskine, and Lazarsfeld that gives a bound on the regularity of a possibly singular curve given its degree and the dimension of the ambient projective space. To do so, we show new results linking the shape of multigraded resolutions of a sheaf to its regularity region.
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Notes
One can compute using Macaulay2 that the actual regularity region is \((2,2) + {{\mathbb {N}}}^2\).
The main bounds in [46] are for curves embedded in \({{\mathbb {P}}}^{d_1} \times {{\mathbb {P}}}^{d_2}\) where \(d_1,d_2 > 1\) with birational projections onto each factor.
References
Almousa, A., Bruce, J., Loper, M., Sayrafi, M.: The virtual resolutions package for Macaulay. J. Softw. Algebra Geomet. 10(1), 51–60 (2020)
Arbarello, E., Cornalba, M., Griffiths, P.A., Harris, J.: Geometry of Algebraic Curves Volume i, Grundlehren der mathematischen Wissenschaften. Springer New York, New York (1985)
Botbol, N., Chardin, M.: Castelnuovo mumford regularity with respect to multigraded ideals. J. Algebra 474, 361–392 (2017)
Bruce, J., Heller, L.C., Sayrafi, M.: Characterizing multigraded regularity on products of projective spaces (2021). arXiv:2110.10705
Bruce, J., Heller, L.C., Sayrafi, M.: Bounds on multigraded regularity (2022). arXiv:2208.11115
Brown, M.K., Erman, D.: Tate resolutions on toric varieties (2021). arXiv:2108.03345
Brown, M.K., Erman, D.: Linear syzygies of curves in weighted projective space (2023). arXiv:2301.09150
Brown, M.K., Erman, D.: A short proof of the hanlon-hicks-lazarev theorem (2023). arXiv:2303.14319
Beilinson, A.A.: Coherent sheaves on \(\mathbb{P} ^n\) and problems of linear algebra. Funct. Anal. Appl. 12, 214–216 (1978)
Berkesch, C., Erman, D., Smith, G.G.: Virtual resolutions for a product of projective spaces. Algebra Geom. 7(4), 460–481 (2020)
Berkesch, C., Klein, P., Loper, M.C., Yang, J.: Homological and combinatorial aspects of virtually Cohen-Macaulay sheaves. Trans. Lond. Math. Soc. 8(1), 413–434 (2021)
Booms-Peot, C., Cobb, J.: Virtual criterion for generalized Eagon-Northcott complexes. J. Pure Appl. Algebra 226(12), 107–138 (2022)
Bruce, J.: Asymptotic syzygies in the setting of semi-ample growth (2019). arXiv:1904.04944
Bruce, J.: The quantitative behavior of asymptotic syzygies for Hirzebruch surfaces. J. Commut. Algebra 14(1), 19–26 (2022)
Brown, M.K., Sayrafi, M.: A short resolution of the diagonal for smooth projective toric varieties of picard rank 2 (2022). arXiv:2208.00562
Bayer, D., Stillman, M.E.: On the complexity of computing syzygies. J. Symb. Comput. 6, 135–147 (1988)
Chardin, M., Holanda, R.: Multigraded tor and local cohomology (2022). arXiv:2211.14357
Costa, L., Miró-Roig, R.M.: m-blocks collections and Castelnuovo-Mumford regularity in multiprojective spaces. Nagoya Math. J. 186, 119–155 (2006)
Chardin, M., Nemati, N.: Multigraded regularity of complete intersections (2020). arXiv:2012.14899
Eisenbud, D., Erman, D., Schreyer, F.-O.: Tate resolutions for products of projective spaces. Acta Math. Vietnam 40, 5–36 (2014)
Eisenbud, D.: Geometry of Syzygies. Graduate Texts in Mathematics. Springer New York, New York (2005)
Ein, L., Lazarsfeld, R.: Syzygies and Koszul cohomology of smooth projective varieties of arbitrary dimension. Invent. Math. 111, 51–67 (1993)
Ein, L., Niu, W., Park, J.: Singularities and syzygies of secant varieties of nonsingular projective curves. Invent. Math. 222(2), 615–665 (2020)
Fantechi, B., Göttsche, L., Illusie, L., Kleiman, S.L., Nitsure, N., Vistoli, A.: Fundamental algebraic geometry, Mathematical Surveys and Monographs, vol. 123, American Mathematical Society, Providence, RI (2005). Grothendieck’s FGA explained. MR2222646
Fulton, W.: Intersection Theory. Springer New York, New York (1998)
Green, M., Lazarsfeld, R.: A simple proof of petri’s theorem on canonical curves. Prog. Math. 60, 129–142 (1985)
Gao, J., Li, Y., Loper, M.C., Mattoo, A.: Virtual complete intersections in \({\mathbb{P} }^1\times {\mathbb{P} }^1\). J. Pure Appl. Algebra 225(1), 106473 (2021)
Gruson, L., Lazarsfeld, R., Peskine, C.: On a theorem of Castelnuovo, and the equations defining space curves. Invent. Math. 72(3), 491–506 (1983)
Gotzmann, G.: Eine bedingung für die flachheit und das hilbertpolynom eines graduierten ringes. Math. Z. 158, 61–70 (1978)
Gruson, L., Peskine, C.: Genre des courbes de l’espace projectif. In: Olson, L.D. (eds) Algebraic Geometry. Lecture Notes in Mathematics, vol 687. Springer, Berlin, Heidelberg. (1978). https://link.springer.com/chapter/10.1007/BFb0062927#citeas
Gruson, L., Peskine, C.: Postulation des courbes gauches, In: Ciliberto, C., Ghione, F., Orecchia, F. (eds) Algebraic Geometry – Open Problems. Lecture Notes in Mathematics, vol 997. Springer, Berlin, Heidelberg. (1983). https://link.springer.com/chapter/10.1007/BFb0061646
Green, M.L.: Koszul cohomology and the geometry of projective varieties. J. Differ. Geom. 19, 125–171 (1984)
Grayson, D.R., Stillman, M.E.: Macaulay2, a software system for research in algebraic geometry. available at https://macaulay2.com. Accessed 1 Dec 2022
Hà, H.T.: Multigraded regularity, \(\text{ a}^{*}\)-invariant and the minimal free resolution. J. Algebra 310(1), 156–179 (2007)
Hering, M.: Multigraded regularity and the Koszul property. J. Algebra 323(4), 1012–1017 (2010)
Hanlon, A., Hicks, J., Lazarev, O.: Resolutions of toric subvarieties by line bundles and applications (2023). arXiv:2303.03763
Hà, H.T., Strunk, B.: Minimal free resolutions and asymptotic behavior of multigraded regularity. J. Algebra 311(2), 492–510 (2007)
Hering, M., Schenck, H., Smith, G.G.: Syzygies, multigraded regularity and toric varieties. Compos. Math. 142, 1499–1506 (2006)
Hà, H.T., Van Tuyl, A.: The regularity of points in multi-projective spaces. J. Pure Appl. Algebra 187, 153–167 (2002)
William Hoffman, J., Wang, H.: Castelnuovo.mumford regularity in biprojective spaces. Adv. Geom. 4, 513–536 (2002)
Kemeny, M.: Universal secant bundles and syzygies of canonical curves, Invent. Math., pp. 1–32 (2020)
Kwak, S.: Generic projections, the equations defining projective varieties and Castelnuovo regularity. Math. Z. 234, 413–434 (2000)
Kwak, S.: Castelnuovo regularity for smooth subvarieties of dimensions 3 and 4, Journal of Algebraic. Geometry 7, 195–206 (1998)
Lazarsfeld, Robert K.: Positivity in Algebraic Geometry I: Classical Setting: Line Bundles and Linear series, vol. 48. Springer (2017)
Loper, M.: What makes a complex a virtual resolution? Trans. Am. Math. Soc. Ser. B 8(28), 885–898 (2021)
Lozovanu, V.: Regularity of smooth curves in biprojective spaces. J. Algebra 322, 2355–2365 (2008)
Lozovanu, V., Smith, G.G.: Vanishing theorems and the multigraded regularity of nonsingular subvarieties, arXiv:1208.0484 (2012)
McCullough, J., Peeva, I.: Counterexamples to the eisenbud-goto regularity conjecture. J. Am. Math. Soc. 31, 473–496 (2017)
Maclagan, D., Smith, G.G.: Uniform bounds on multigraded regularity, Journal of Algebraic. Geometry 14, 137–164 (2003)
Maclagan, D., Smith, G.G.: Multigraded castelnuovo-mumford regularity. Journal für die reine und angewandteMathematik 571, 179–212 (2004)
Okonek, C., Schneider, M., Spindler, H.: Vector Bundles on Complex Projective Spaces. Birkhäuser, Basel (1980)
Stacks Project Authors, Stacks project
Sidman, J., Van Tuyl, A.: Multigraded regularity: syzygies and fat points. Beitr. Algebra Geom. 47(1), 67–87 (2006)
Szpiro, L.: Travaux de kempf, kleiman, laksov sur les diviseurs exceptionnels. Séminaire bourbaki 1971(72), 339–353 (1973)
Weibel, C.A.: An introduction to homological algebra, Cambridge Studies in Advanced Mathematics, vol. 38, Cambridge University Press, Cambridge (1994). MR1269324
Yang, J.: Virtual resolutions of monomial ideals on toric varieties, Proc. Am. Math. Soc. Ser. B (2019)
Acknowledgements
Thanks to Daniel Erman for his valuable insight during this project. Thanks also to Michael Kemeny who helped me understand some of the arguments in [28], to Rob Lazarsfeld for alerting me to a different treatment of the \(n=2\) case by his student in [46], and to an anonymous reviewer for their thorough reading and detailed suggestions that greatly improved the paper. The computer algebra system Macaulay2 [33] was used extensively, in particular, the VirtualResolutions package [1].
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Cobb, J. Syzygies of curves in products of projective spaces. Math. Z. 306, 27 (2024). https://doi.org/10.1007/s00209-023-03422-3
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DOI: https://doi.org/10.1007/s00209-023-03422-3