Incidence bounds related to circular Furstenberg sets

Series
Analysis Seminar
Time
Wednesday, April 1, 2026 - 2:00pm for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Sarah Tammen – University of Wisconsin-Madison – tammen2@wisc.eduhttps://sites.google.com/view/sarahtammen/home
Organizer
Anastasios Fragkos

I will present on recent work  - joint with John Green, Terence Harris, Kevin Ren, and Yumeng Ou -  towards proving lower bounds for the dimensions of Furstenberg sets of circles and sine curves in the plane.  A circular $(u,v)$-Furstenberg set is a set that contains a $u$-dimensional subset of each circle from a $v$-dimensional family of circles.  One can approach the circular Furstenberg problem by proving estimates for the number of incidences between families of $\delta$-disks and $\delta$-annuli that satisfy certain dimension conditions.  For different values of $u$ and $v$, we prove incidence estimates using local smoothing and using trilinear restriction estimates for the cone in $\mathbb{R}^3$.  As time permits, I will discuss work relevant to proving dimension estimates for Furstenberg sets of sine curves (which satisfy all of the bounds we prove for circular Furstenberg sets) and/or work for Furstenberg sets of curves that satisfy a more general cinematic curvature condition.