On Lack of Existence of Local Formulas for Z_2 invariants
Speaker: Ahmad Reza Haj Saeedi Sadegh, Dartmouth College
Date: Feb 4, 2024
Abstract: In the 5th volume of their celebrated articles (The Index of Elliptic Operators: V), Atiyah and Singer discuss elliptic differential operators over real numbers instead of complex numbers. These real elliptic operators usually produce more refined indices than the usual index of complex elliptic operators. Such indices seem not to be accessible via local expressions in general. However, there are still topological formulas for these indices in K-theoretical terms. In certain settings, we give topological formulas in terms of the integral of characteristic forms.