Presented By: Algebraic Geometry Seminar - Department of Mathematics
Algebraic Geometry Seminar: Crepant resolutions via stacks
Jeremy Usatine, Florida State University
Consider an invariant that behaves nicely for smooth varieties, such as Euler number, Betti numbers, or Hodge numbers. Suppose we want a version of this invariant for singular varieties that sees interesting information about the singularities. I will discuss how this naturally leads to the notion of crepant resolutions of singularities. However, crepant resolutions (by varieties) are rare in practice. I will discuss joint work with M. Satriano in which we show that crepant resolutions actually exist in broad generality, as long as one is willing to consider algebraic stacks. Specifically, any variety with log-terminal singularities admits a crepant resolution by a smooth algebraic stack. As one consequence, in joint work with J. Huang and M. Satriano, we obtain a cohomological interpretation for Batyrev's stringy Hodge numbers. This talk will not assume familiarity with stacks.