Unipotent nearby cycles and nearby cycles over general bases

Andrew Salmon

Journal of Singularities
volume 27 (2024), 31-46

Received: 19 May 2023. In revised form: 31 January 2024

DOI: 10.5427/jsing.2024.27b


Abstract:

We show that under some conditions, two constructions of nearby cycles over general bases coincide. More specifically, we show that under the assumption of Psi-factorizability, the constructions of unipotent nearby cycles over an affine space by Achar and Riche can be described using the theory of nearby cycles over general bases via the vanishing topos. In particular, this applies to nearby cycles of Satake sheaves on Beilinson-Drinfeld Grassmannians with parahoric ramification.


Author(s) information:

Andrew Salmon
email: asalmon@alum.mit.edu