The APDE seminar on Monday, 10/14, will be given by Gabriele Benomio (GSSI) in-person in **Evans 740,** and will also be broadcasted online via Zoom from **4:10pm to 5:00pm PST**. To participate, please email Federico Pasqualotto () or Mengxuan Yang ().

**Title:** A new gauge for gravitational perturbations of Kerr spacetimes

**Abstract:** I will present a new geometric framework to address the stability of the Kerr solution to gravitational perturbations in the full sub-extremal range. Central to the framework is a new formulation of nonlinear gravitational perturbations of Kerr in a geometric gauge tailored to the outgoing principal null geodesics of Kerr. The main features of the framework will be illustrated in the context of the linearised theory, which serves as a fundamental building block in nonlinear applications.