Copyright © 2006 Hindawi Publishing Corporation. All rights reserved.
Stable spherical varieties and their moduli
Department of Mathematics, University of Georgia Athens, GA 30602, USA E-mail address: valery{at}math.uga.edu
Institut Fourier BP 74, 38402 Saint-Martin d'Hères Cedex, France E-mail address: michel.brion{at}ujf-grenoble.fr
We introduce a notion of stable spherical variety which includes the spherical varieties under a reductive group G and their flat equivariant degenerations. Given any projective space
where G acts linearly, we construct a moduli space for stable spherical varieties over
, that is, pairs (X,f), where X is a stable spherical variety and f:X
is a finite equivariant morphism. This space is projective, and its irreducible components are rational. It generalizes the moduli space of pairs (X,D), where X is a stable toric variety and D is an effective ample Cartier divisor on X which contains no orbit. The equivariant automorphism group of
acts on our moduli space; the spherical varieties over
and their stable limits form only finitely many orbits. A variant of this moduli space gives another view to the compactifications of quotients of thin Schubert cells constructed by Kapranov and Lafforgue.
References
- Alexeev V. Complete moduli in the presence of semiabelian group action. Annals of Mathematics. Second Series (2002) 155(3):611708.
- Alexeev V. Compactified Jacobians and Torelli map. Publications of the Research Institute for Mathematical Sciences, Kyoto University (2004) 40(4):12411265.[CrossRef]
- Alexeev V., Brion M. Stable reductive varieties. I. Affine varieties. Inventiones Mathematicae (2004) 157(2):227274.[Web of Science]
- Alexeev V., Brion M. Stable reductive varieties. II. Projective case. Advances in Mathematics (2004) 184(2):380408.[CrossRef][Web of Science]
- Alexeev V., Brion M. Moduli of affine schemes with reductive group action. Journal of Algebraic Geometry (2005) 14(1):83117.[Web of Science]
- Bravi P., Pezzini G. Wonderful varieties of type D. Representation Theory (2005) 9:578637.[CrossRef]
- Brion M., Pauer F. Valuations des espaces homogènes sphériques. Commentarii Mathematici Helvetici (1987) 62(2):265285.[CrossRef][Web of Science]
- Delzant T. Classification des actions hamiltoniennes complètement intégrables de rang deux. Annals of Global Analysis and Geometry (1990) 8(1):87112.[CrossRef]
- Demazure M., Grothendieck A., eds. Séminaire de Géométrie Algébrique du Bois Marie 1962/1964 (SGA 3). Schémas en Groupes. I. In: Lecture Notes in Mathematics (1970) 151. Berlin: Springer. xv+564.
- Esnault H., Viehweg E. Lectures on Vanishing Theorems. In: DMV Seminar (1992) 20. Basel: Birkhäuser. vi+164.
- Gel'fand I. M., Kapranov M. M., Zelevinsky A. V. Discriminants, Resultants, and Multidimensional Determinants. In: Mathematics: Theory & Applications (1994) Massachusetts: Birkhäuser Boston. x+523.
- Grosshans F. D. Algebraic Homogeneous Spaces and Invariant Theory. In: Lecture Notes in Mathematics (1997) 1673. Berlin: Springer. vi+148.
- Guillemin V., Sjamaar R. Convexity theorems for varieties invariant under a Borel subgroup. Pure and Applied Mathematics Quarterly (2006) 2(3):637653.[Web of Science]
- Hacking P., Keel S., Tevelev J. Compactification of the moduli space of hyperplane arrangements. Journal of Algebraic Geometry (2006) 15(4):657680.[Web of Science]
- Haiman M., Sturmfels B. Multigraded Hilbert schemes. Journal of Algebraic Geometry (2004) 13(4):725769.[Web of Science]
- Hartshorne R. Algebraic Geometry. In: Graduate Texts in Mathematics, no. 52 (1977) New York: Springer. xvi+496.
- Hu Y. (W,R)-matroids and thin Schubert-type cells attached to algebraic torus actions. Proceedings of the American Mathematical Society (1995) 123(9):26072617.[CrossRef][Web of Science]
- Kapranov M. M. Chow quotients of Grassmannians. I. In: I. M. Gel'fand Seminar (1993) 16. Rhode Island: American Mathematical Society. 29110. Adv. Soviet Math.
- Kapranov M. M., Sturmfels B., Zelevinsky A. V. Quotients of toric varieties. Mathematische Annalen (1991) 290(4):643655.[CrossRef][Web of Science]
- Knop F. The Luna-Vust theory of spherical embeddings. (1991) Proceedings of the Hyderabad Conference on Algebraic Groups, 1989: Hyderabad. Madras: Manoj Prakashan. 225249.
- Knop F. Über Bewertungen, welche unter einer reduktiven Gruppe invariant sind. Mathematische Annalen (1993) 295(2):333363.[CrossRef][Web of Science]
- Knop F. A Harish-Chandra homomorphism for reductive group actions. Annals of Mathematics. Second Series (1994) 140(2):253288.
- Knop F. Automorphisms, root systems, and compactifications of homogeneous varieties. Journal of the American Mathematical Society (1996) 9(1):153174.[CrossRef][Web of Science]
- Knop F., Van Steirteghem B. Classification of smooth affine spherical varieties. Transformation Groups (2006) 11(3):495516.[CrossRef][Web of Science]
- Kollár J. Rational Curves on Algebraic Varieties. In: Ergebnisse der Mathematik und ihrer Grenzgebiete. 3 (1996) 32. Berlin: Springer. viii+320.
- Lafforgue L. Chirurgie des Grassmanniennes. In: CRM Monograph Series (2003) 19. Rhode Island: American Mathematical Society. xx+170.
- Laumon G., Moret-Bailly L. Champs Algébriques. In: Ergebnisse der Mathematik und ihrer Grenzgebiete. 3 (2000) 39. Berlin: Springer. xii+208.
- Luna D. Variétés sphériques de type A. Publications Mathématiques de l'Institut des Hautes Études Scientifiques (2001) (94):161226.
- Luna D., Vust Th. Plongements d'espaces homogènes. Commentarii Mathematici Helvetici (1983) 58(2):186245.[CrossRef][Web of Science]
- Mumford D., Fogarty J., Kirwan F. Geometric Invariant Theory. In: Ergebnisse der Mathematik und ihrer Grenzgebiete (2) (1994) 34, 3rd. Berlin: Springer. xiv+292.
- Popov V. L. Contractions of actions of reductive algebraic groups. Mathematics of the USSR Sbornik (1987) 58(2):311335.[CrossRef]
- Popov V. L., Vinberg E. B. Invariant theory. In: Algebraic Geometry IV (1994) 55. Berlin: Springer. 123284. Encyclopaedia of Mathematical Sciences.
- Raynaud M. Faisceaux Amples sur les Schémas en Groupes et les Espaces Homogènes. In: Lecture Notes in Math. (1970) 119. Berlin: Springer.
- Sjamaar R. Convexity properties of the moment mapping re-examined. Advances in Mathematics (1998) 138(1):4691.[CrossRef][Web of Science]
- Sumihiro H. Equivariant completion. Journal of Mathematics of Kyoto University (1974) 14:128.
- Viehweg E. Quasi-Projective Moduli for Polarized Manifolds. In: Ergebnisse der Mathematik und ihrer Grenzgebiete (3) (1995) 30. Berlin: Springer. viii+320.
- Wasserman B. Wonderful varieties of rank two. Transformation Groups (1996) 1(4):375403.[CrossRef]
- Woodward C. The classification of transversal multiplicity-free group actions. Annals of Global Analysis and Geometry (1996) 14(1):342.[CrossRef][Web of Science]
| ||||||||||||||||||||||||||||||||||||||||||||||||||||