Equivariant Hirzebruch class for singular varieties

Abstract

The Hirzebruch $t{d}_y(X)$ class of a complex manifold X is a formal combination of Chern characters of the sheaves of differential forms multiplied by the Todd class. The related ${\chi }_y$-genus admits a generalization for singular complex algebraic varieties. The equivariant version of the Hirzebruch class can be developed as well. The general theory applied in the situation when a torus acts on a singular variety allows to apply powerful tools as the Localization Theorem of Atiyah and Segal for equivariant K-theory and Berline-Vergne formula for equivariant cohomology. We obtain a meaningful invariant of a germ of singularity. When it is made explicit it turns out to be just a polynomial in characters of the torus. We discuss a relation of the properties of a singularity germ with its local Hirzebruch class. The issue of positivity of coefficients in a certain expansion remains mysterious. The quotient singularities, toric singularities, the singularities of Schubert varieties are of special interest.

38 pages, 3 figures

References in corpus (6)

• Governing Singularities of Schubert Varieties
• Equivariant Chern classes of singular algebraic varieties with group actions
• Equivariant Todd Classes for Toric Varieties
• Computing equivariant characteristic classes of singular varieties
• Positivity of Chern classes of Schubert cells and varieties
• Hirzebruch class and Bialynicki-Birula decomposition

Cited by in corpus (1)

• Computing equivariant characteristic classes of singular varieties