Valentina Kiritchenko
University of Toronto
A Gauss-Bonnet theorem for subvarieties of reductive groups
Abstract: I will prove an analog of the Gauss-Bonnet formula for subvarieties of arbitrary reductive groups. This formula holds for all subvarieties (possibly singular) invariant under the adjoint action and expresses their Euler characteristic in terms of complex links of some stratification of a reductive group. In the case when a subvariety X is smooth and closed, we just get that its Euler characteristic is equal to (-1)^dim(X) times the Gaussian degree of X. The notion of Gaussian degree will be explained.