Abstract
We study Edidin and Graham's equivariant Chow groups in the case of torus actions. Our main results are: (i) a presentation of equivariant Chow groups in terms of invariant cycles, which shows how to recover usual Chow groups from equivariant ones; (ii) a precise form of the localization theorem for torus actions on projective, nonsingular varieties; (iii) a construction of equivariant multiplicities, as functionals on equivariant Chow groups; (iv) a construction of the action of operators of divided differences on theT-equivariant Chow group of any scheme with an action of a reductive group with maximal torusT. We apply these results to intersection theory on varieties with group actions, especially to Schubert calculus and its generalizations. In particular, we obtain a presentation of the Chow ring of any smooth, projective spherical variety.
Similar content being viewed by others
References
A. Arabia,Cycles de Schubert et cohomologie équivariante de K/T, Invent. Math.85 (1986), 39–52.
qI. Н. Бернштейн, И. М. Гелъфанд, С. И. Гелъфанд, Кпетки Шуберта и когомопогии пространств G/P,YMH XXVIII 3 (171) (1973), 3–26. English translation: I. N. Bernstein, I. M. Gelfand and S. I. Gelfand,Schubert cells and cohomology of the spaces G/P, Russian Math. Surveys,28 (1973), 1–26.
A. Bialynicki-Birula,Some theorems on actions of algebraic groups, Ann. Math.98 (1973), 480–497.
A. Bialynicki-Birula,On fixed points of torus actions on projective varieties, Bull. Acad. Polon. Sci. Séri. Sci. Math. Astronom. Phys.22 (1974), 1097–1101.
A. Bialynicki-Birula,Some properties of the decomposition of algebraic varieties determined by the action of a torus, Bull. Acad. Polon. Sci. Séri. Sci. Math. Astronom. Phys.24, (1976), 667–674.
E. Bifet, C. De Concini and C. Procesi,Cohomology of regular embeddings, Adv. Math.82 (1990), 1–34.
A. Borel,Linear Algebraic Groups Springer-Verlag, New York, 1991. Russian translation: A. Борелъ, Линейные агебраические руппы, Москва, Мир, 1972.
W. Borho, J-L. Brylinski and R. MacPherson,Nilpotent Orbits, Primitive Ideals, and Characteristic Classes, Birkhäuser, Boston, 1989.
P. Bressler and S. Evens,The Schubert calculus, braid relations, and generalized cohomology, Trans. AMS317 (1990), 799–811.
M. Brion,Piecewise polynomial functions, convex polytopes and enumerative geometry, Parameter spaces (P. Pragacz, ed.), Banach Center Publications, 1996, pp. 25–44.
M. Brion and M. Vergne,An equivariant Riemann-Roch theorem for complete, simplicial toric varieties, J. Crelle482 (1997), 67–92.
J. B. Carrell,The Bruhat graph of a Coxeter group, a conjecture of Deodhar, and rational smoothness of Schubert varieties, Proc. Symp. in Pure Math., 1994, pp. 53–61.
M. Demazure,Invariants symétriques entiers des groupes de Weyl et torsion, Invent. Math.21 (1973), 287–301.
M. Demazure,Désingularisation des variétés de Schubert généralisées, Ann. Scient. Éc. Norm. Sup.7 (1974), 53–88.
D. Edidin and W. Graham,Equivariant intersection theory, preprint 1996.
D. Edidin and W. Graham,Localization in equivariant intersection theory and the Bott residue formula, preprint 1996.
W. Fulton,Intersection Theory, Springer-Verlag, New York, 1984. Russian translation: У, Фултон, Теория пересечений, Москва, Мир, 1989.
W. Fulton,Introduction to Toric Varieties, Princeton University Press, Princeton, 1993.
W. Fulton,Flags, Schubert polynomials, degeneracy loci and determinantal formulas, Duke Math. J.65 (1992), 381–420.
W. Fulton,Schubert varieties in flag bundles for classical groups, Proceedings of the Hirzebruch 65 Conference on Algebraic Geometry, Bar-Ilan University, 1996, pp. 241–262.
W. Fulton, R. MacPherson, F. Sottile and B. Sturmfels,Intersection theory on spherical varieties, J. Alg. Geom.4 (1995), 181–193.
H. Gillet,Riemann-Roch theorems for higher algebraic K-theory, Adv. Math.40 (1981), 203–289.
M. Goresky, R. Kottwitz and R. MacPherson,Equivariant cohomology, Koszul duality, and the localization theorem, preprint 1996.
W. Graham,The class of the diagonal in flag bundles, preprint 1996.
A. Joseph,On the variety of a highest weight module, J. Algebra88 (1984), 238–278.
F. Kirwan,Cohomology of Quotients in Symplectic and Algebraic Geometry, Princeton University Press, Princeton, 1984.
F. Knop,On the set of orbits for a Borel subgroup, Comment. Math. Helv.70 (1995), 285–309.
B. Kostant and S. Kumar,The nil Hecke ring and cohomology of G/P for a Kac-Moody group G. Adv. Math.,62 (1986), 187–237.
B. Kostant and S. Kumar,T-equivariant K-theory of generalized flag varieties, J. Differ. Geom.32 (1990), 549–603.
S. Kumar,The nil Hecke ring and singularity of Schubert varieties, Invent. math.123 (1996), 471–506.
P. Littelmann and C. Procesi,Equivariant cohomology of wonderful compactifications, Operator Algebras, Unitary Representations, Enveloping Algebras, and Invariant Theory, Birkhäuser, Basel, 1990.
M. Nyenhuis,Equivariant Chow groups and multiplicities, preprint 1996.
M. Nyenhuis,Equivariant Chow groups and equivariant Chern classes, preprint 1996.
P. Polo,On Zariski tangent spaces of Schubert varieties, and a proof of a conjecture of Deodhar, Indag. Math.5 (1994), 483–493.
P. Pragacz,Symmetric polynomials and divided differences in formulas of intersection theory, Parameter Spaces, Banach Center Publications, 1996, pp. 125–177.
P. Pragacz and J. Ratajski, Formulas for Lagrangian and orthogonal degeneracy loci: the\(\bar Q\)-polynomials, Compositio Math., to appear.
R. W. Richardson and T. A. Springer,The Bruhat order on symmetric varieties, Geometriae Dedicata35, (1990), 389–436.
W. Rossmann,Equivariant multiplicities on complex varieties, Astérisque173–174 (1989), 313–330.
W. Smoke,Dimension and multiplicity for graded algebras, J. Algebra21 (1972), 149–173.
E. Strickland,A vanishing theorem for group compactifications, Math. Ann.277 (1987), 165–171.
A. Vistoli,Characteristic classes of principal bundles in algebraic intersection theory, Duke Math. J.58 (1989), 299–315.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Brion, M. Equivariant Chow groups for torus actions. Transformation Groups 2, 225–267 (1997). https://doi.org/10.1007/BF01234659
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01234659