Available in electronic format
Available in print format
Journal of the American Mathematical Society
Journal of the American Mathematical Society
ISSN: 1088-6834(e) ISSN: 0894-0347(p)
     

Geometric invariant theory and flips

Author(s): Michael Thaddeus
Journal: J. Amer. Math. Soc. 9 (1996), 691-723.
MSC (1991): Primary 14L30, 14D20
Retrieve article in: PDF
This article is available free of charge

Abstract | References | Similar articles | Additional information

Abstract: We study the dependence of geometric invariant theory quotients on the choice of a linearization. We show that, in good cases, two such quotients are related by a flip in the sense of Mori, and explain the relationship with the minimal model program. Moreover, we express the flip as the blow-up and blow-down of specific ideal sheaves, leading, under certain hypotheses, to a quite explicit description of the flip. We apply these ideas to various familiar moduli problems, recovering results of Kirwan, Boden-Hu, Bertram-Daskalopoulos-Wentworth, and the author. Along the way we display a chamber structure, following Duistermaat-Heckman, on the space of all linearizations. We also give a new, easy proof of the Bialynicki-Birula decomposition theorem.


References:

1.
M.F. Atiyah, On analytic surfaces with double points, Proc. R. Soc. Lond. A 247 (1958) 237--44. MR 20:2472

2.
A. Bertram, G. Daskalopoulos, and R. Wentworth, Gromov invariants for holomorphic maps from Riemann surfaces to Grassmannians, J. Amer. Math. Soc., to appear.

3.
U.N. Bhosle, Parabolic vector bundles on curves, Arkiv för Mat. 27 (1989) 15--22. MR 90f:14007

4.
A. Bialynicki-Birula, Some theorems on actions of algebraic groups, Ann. Math. 98 (1973) 480--497. MR 51:3186

5.
S. Bradlow, Special metrics and stability for holomorphic bundles with global sections, J. Diff. Geom. 33 (1991) 169--213. MR 91m:32031

6.
S. Bradlow and G. Daskalopoulos, Moduli of stable pairs for holomorphic bundles over Riemann surfaces, Int. J. Math. 2 (1991) 477-513. MR 93b:58026

7.
M. Brion and C. Procesi, Action d'un tore dans une variété projective, Operator algebras, unitary representations, enveloping algebras, and invariant theory, (A. Connes, M. Duflo, A. Joseph, and R. Rentschler, eds.), Birkhauser, 1990, pp. 509--539. MR 92m:14061

8.
H. Boden and Y. Hu, Variation of moduli of parabolic bundles, Math. Ann., to appear.

9.
I. Dolgachev and Y. Hu, Variation of geometric invariant theory quotients, preprint.

10.
J.-M. Drezet and M.S. Narasimhan, Groupe de Picard des variétés de modules de fibrés semi-stables sur les courbes algébriques, Inv. Math. 97 (1989) 53--94. MR 90d:14008

11.
J.J. Duistermaat and G.J. Heckman, On the variation in the cohomology of the symplectic form of the reduced phase space, Inv. Math. 69 (1982) 259--268. Addendum: 72 (1983) 153--158. MR 84h:58051a,b

12.
D. Gieseker, On the moduli of vector bundles on an algebraic surface, Ann. of Math. 106 (1977) 45--60. MR 81h:14014

13.
A. Grassi and J. Kollár, Log canonical models, Astérisque 211 (1992) 29--45. MR 94f:14013

14.
A. Grothendieck, Sur quelques points d'algèbre homologique, Tôhoku Math. J. 9 (1957) 119--221. MR 21:1328

15.
A. Grothendieck, Technique de descente et théorèmes d'existence en géométrie algébrique, IV: Les schémas de Hilbert, Sém. Bourbaki 1960-61, Exp. 221; reprinted in Fondements de la géométrie algébrique, Secrétariat Math., Paris, 1962. MR 26:3566

16.
R. Hartshorne, Algebraic geometry, Springer-Verlag, 1977. MR 57:3116

17.
Y. Hu, The geometry and topology of quotient varieties of torus actions, Duke Math. J. 68 (1992) 151--184. Erratum: 68 (1992) 609. MR 93k:14019a,b

18.
F.C. Kirwan, Cohomology of quotients in algebraic and symplectic geometry, Princeton, 1984. MR 86i:58050

19.
D. Luna, Slices étales, Mém. Soc. Math. France 33 (1973) 81--105. MR 49:7269

20.
I.G. Macdonald, Symmetric products of an algebraic curve, Topology 1 (1962) 319--343. MR 27:1445

21.
V.B. Mehta and C.S. Seshadri, Moduli of vector bundles on curves with parabolic structures, Math. Ann. 248 (1980) 205--239. MR 81i:14010

22.
S. Mori, Flip theorem and the existence of minimal models for 3-folds, J. Amer. Math. Soc. 1 (1988) 117--253. MR 89a:14048

23.
D. Mumford and J. Fogarty, Geometric invariant theory, second enlarged edition, Springer-Verlag, 1982. MR 86a:14006

24.
P.E. Newstead, Introduction to moduli problems and orbit spaces, Tata Inst., Bombay, 1978. MR 81k:14002

25.
C.S. Seshadri, Quotient spaces modulo reductive algebraic groups, Ann. of Math. 95 (1972) 511--556. MR 46:9044

26.
C.S. Seshadri, Fibrés vectoriels sur les courbes algébriques, Astérisque 96 (1982). MR 85b:14023

27.
M. Thaddeus, Stable pairs, linear systems and the Verlinde formula, Inv. Math. 117 (1994) 317--353. MR 95e:14006

28.
M. Thaddeus, Toric quotients and flips, Proceedings of the 1993 Taniguchi symposium, (K. Fukaya, M. Furuta, and T. Kohno, eds.), World Scientific, 1994, pp. 193--213. MR 96b:14067


Similar Articles:

Retrieve articles in Journal of the American Mathematical Society with MSC (1991): 14L30, 14D20

Retrieve articles in all Journals with MSC (1991): 14L30, 14D20


Additional Information:

Michael Thaddeus
Affiliation: St. John's College, Oxford, England
Address at time of publication: Department of Mathematics, Harvard University, 1 Oxford St., Cambridge, Massachusetts 02138
Email: thaddeus@math.harvard.edu

DOI: 10.1090/S0894-0347-96-00204-4
PII: S 0894-0347(96)00204-4
Received by editor(s): November 11, 1994
Received by editor(s) in revised form: March 23, 1995
Copyright of article: Copyright 1996, American Mathematical Society


  AMS Website Logo Small Comments: webmaster@ams.org
© Copyright 2009, American Mathematical Society
Privacy Statement
Search the AMSPowered by Google