|Date: Thursday, April 14, 2022
Location: https://umich.zoom.us/j/96274532499 (password: algebra) Virtual East Hall (4:00 PM to 5:00 PM)
Title: A derived splinter characterization of klt singularities in characteristic zero
Abstract: A ring R is a derived splinter if for every proper, surjective morphism $\pi:Y\to\Spec R$ the map $R\to R\pi_*O_Y$ splits in the derived category of R-modules. Kovács has shown that in characteristic zero this is equivalent to R having rational singularities. In this talk, I’ll discuss how klt singularities, which are nicer than rational singularities, can be characterized in a similar fashion. Specifically, I’ll show that a ring R has kit-type if and only if, for all sufficiently large regular alterations $\pi:Y\to\Spec R$, there is a splitting of $R\to R\pi_*O_Y$ that factors through $\pi_*\omega_Y$.
Speaker: Peter McDonald
Institution: University of Utah