Abstract
According to Mukai and Iliev, a smooth prime Fano threefold \(X\) of genus \(9\) is associated with a surface \(\mathbb{P }(\mathcal{V })\), ruled over a smooth plane quartic \(\varGamma \), and the derived category of \(\varGamma \) embeds into that of \(X\) by a theorem of Kuznetsov. We use this setup to study the moduli spaces of rank-\(2\) stable sheaves on \(X\) with odd determinant. For each \(c_2 \ge 7\), we prove that a component of their moduli space \(\mathsf{M}_X(2,1,c_2)\) is birational to a Brill–Noether locus of vector bundles with fixed rank and degree on \(\varGamma \), having enough sections when twisted by \(\mathcal{V }\). For \(c_2=7\), we prove that \(\mathsf{M}_X(2,1,7)\) is isomorphic to the blow-up of the Picard variety \(\text{ Pic}^{2}({\varGamma })\) along the curve parametrizing lines contained in \(X\).
Similar content being viewed by others
References
Ancona, V., Ottaviani, G.: Stability of special instanton bundles on \({ P}^{2n+1}\). Trans. Am. Math. Soc. 341(2), 677–693 (1994)
Arbarello, E., Cornalba, M., Griffiths, P.A., Harris, J.: Geometry of algebraic curves, vol. I. Grundlehren der Mathematischen Wissenschaften [Fundamental Principles of Mathematical Sciences], vol. 267. Springer, New York (1985)
Atiyah, M.F., Hitchin, N.J., Drinfel’d, V.G., Manin, Y.I.: Construction of instantons. Phys. Lett. A 65(3), 185–187 (1978)
Atiyah, M.F., Ward, R.S.: Instantons and algebraic geometry. Commun. Math. Phys. 55(2), 117–124 (1977)
Barth, W.: Some properties of stable rank-\(2\) vector bundles on \({ P}_{n}\). Math. Ann. 226(2), 125–150 (1977)
Barth, W., Hulek, K.: Monads and moduli of vector bundles. Manuscripta Math. 25(4), 323–347 (1978)
Bondal, A.I.: Representations of associative algebras and coherent sheaves. Izv. Akad. Nauk SSSR Ser. Mat. 53(1), 25–44 (1989)
Bondal, A.I., Orlov, D.O.: Semiorthogonal decomposition for algebraic varieties. ArXiv:alg-geom/9506012 (1995)
Brambilla, M.C., Faenzi, D.: Vector bundles on Fano threefolds of genus 7 and Brill-Noether loci. ArXiv:math.AG/0810.3138 (2008)
Brambilla, M.C., Faenzi, D.: Moduli spaces of rank-2 ACM bundles on prime Fano threefolds. Mich. Math. J. 60(1), 113–148 (2011)
Căldăraru, A.: Derived categories of sheaves: a skimming. In: Snowbird Lectures in Algebraic Geometry. Contemp. Math., vol. 388, pp. 43–75. American Mathematical Society, Providence (2005)
Casanellas, M., Drozd, E., Hartshorne, R.: Gorenstein liaison and ACM sheaves. J. Reine Angew. Math. 584, 149–171 (2005)
Druel, S.: Espace des modules des faisceaux de rang 2 semi-stables de classes de Chern \(c_1=0, c_2=2\) et \(c_3=0\) sur la cubique de \({ P}^4\). Int. Math. Res. Not. 19, 985–1004 (2000)
Faenzi, D.: Even and odd instanton bundles on Fano threefolds of Picard number 1. ArXiv:math.AG/1109.3858 (2011)
Gelfand, S.I., Manin, Y.I.: Methods of Homological Algebra. Springer, Berlin (1996). Translated from the 1988 Russian original
Gorodentsev, A.L.: Exceptional objects and mutations in derived categories. In: Helices and Vector Bundles. London Math. Soc. Lecture Note Ser., vol. 148, pp. 57–73. Cambridge University Press, Cambridge (1990)
Gruson, L., Laytimi, F., Nagaraj, D.S.: On prime Fano threefolds of genus 9. Int. J. Math. 17(3), 253–261 (2006)
Hartshorne, R.: Residues and duality. Lecture Notes of a Seminar on the Work of A. Grothendieck, given at Harvard 1963/64. With an appendix by P. Deligne. Lecture Notes in Mathematics, No. 20. Springer, Berlin (1966)
Hartshorne, R.: Stable reflexive sheaves. Math. Ann. 254(2), 121–176 (1980)
Hoppe, H.J.: Generischer Spaltungstyp und zweite Chernklasse stabiler Vektorraumbündel vom Rang \(4\) auf \({ P}_{4}\). Math. Z. 187(3), 345–360 (1984)
Huybrechts, D., Lehn, M.: The geometry of moduli spaces of sheaves. Aspects of Mathematics, E31. Friedr. Vieweg & Sohn, Braunschweig (1997)
Iliev, A.: The \({\rm Sp}_3\)-Grassmannian and duality for prime Fano threefolds of genus 9. Manuscripta Math. 112(1), 29–53 (2003)
Iliev, A., Markushevich, D.G.: The Abel-Jacobi map for a cubic threefold and periods of Fano threefolds of degree 14. Doc. Math. 5, 23–47 (2000)
Iliev, A., Ranestad, K.: Geometry of the Lagrangian Grassmannian \({ LG}(3,6)\) with applications to Brill-Noether loci. Michigan Math. J. 53(2), 383–417 (2005)
Iskovskikh, V.A., Prokhorov, Y.G.: Fano varieties. In: Algebraic Geometry, V. Encyclopaedia Math. Sci., vol. 47, pp. 1–247. Springer, Berlin (1999)
Jardim, M., Verbitsky, M.: Trihyperkahler reduction and instanton bundles on \(CP^3\). ArXiv:math.AG/1103.4431 (2011)
Kuznetsov, A.: Hyperplane sections and derived categories. Izv. Ross. Akad. Nauk Ser. Mat. 70(3), 23–128 (2006)
Kuznetsov, A.: Instanton bundles on Fano threefolds. Cent. Eur. J. Math. 10(4), 1198–1231 (2012)
Markushevich, D.G., Tikhomirov, A.S.: The Abel-Jacobi map of a moduli component of vector bundles on the cubic threefold. J. Algebraic Geom. 10(1), 37–62 (2001)
Maruyama, M.: Openness of a family of torsion free sheaves. J. Math. Kyoto Univ. 16(3), 627–637 (1976)
Mukai, S.: Curves, \(K3\) surfaces and Fano \(3\)-folds of genus \(\le 10\). In: Algebraic Geometry and Commutative Algebra, vol. I, pp. 357–377. Kinokuniya, Tokyo (1988)
Mukai, S.: Biregular classification of Fano \(3\)-folds and Fano manifolds of coindex \(3\). Proc. Natl. Acad. Sci. USA 86(9), 3000–3002 (1989)
Mukai, S.: Non-abelian Brill-Noether theory and Fano 3-folds [translation of Sūgaku 49(1), 1–24 (1997); MR 99b:14012]. Sugaku Expositions 14(2), 125–153 (2001)
Tikhomirov, A.S.: Moduli of mathematical instanton vector bundles with odd \(c_2\) on projective space. ArXiv:math.AG/1101.3016 (2011)
Weyman, J.: Cohomology of vector bundles and syzygies. Cambridge Tracts in Mathematics, vol. 149. Cambridge University Press, Cambridge (2003)
Acknowledgments
We would like to thank the referee for many useful comments that helped us to correct some arguments and simplify some of the proofs.
Author information
Authors and Affiliations
Corresponding author
Additional information
M.C. Brambilla was partially supported by INDAM and MIUR. D. Faenzi was partially supported by GRIFGA, ANR-09-JCJC-0097-0 INTERLOW and ANR GEOLMI.
Rights and permissions
About this article
Cite this article
Brambilla, M.C., Faenzi, D. Rank-two stable sheaves with odd determinant on Fano threefolds of genus nine. Math. Z. 275, 185–210 (2013). https://doi.org/10.1007/s00209-012-1131-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00209-012-1131-8