Seminar List

Week of October 8, 2023

Wed Oct 11, 2023
2:00pm to 3:00pm - 510R Rowland Hall - Combinatorics and Probability Jacques Verstraete - (UCSD) The Ramsey number r(4,t) In this talk, I will outline the proof that $r(4,t) = t^{3 - o(1)}$, which solves a long-standing open problem of Erdos. The proof combines a variety of techniques, and lends itself to improving bounds on various other Ramsey numbers $r(F,t)$ where $F$ is a fixed graph., as well as applications to a variety of extremal and Ramsey problems.

Thu Oct 12, 2023
12:00pm to 1:00pm - Online (Zoom) - Nonlinear PDEs Lu Wang - (Yale university) A mean curvature flow approach to density of minimal cones Abstract: Minimal cones are models for singularities in minimal submanifolds, as well as stationary solutions to the mean curvature flow. In this talk, I will explain how to utilize mean curvature flow to yield near optimal estimates on density of topologically nontrivial minimal cones. This is joint with Jacob Bernstein. Joint with VIRTUAL ANALYSIS AND PDE SEMINAR (VAPS). https://sites.google.com/view/vapsemina https://uwmadison.zoom.us/j/97685819574?pwd=OGlucTJLWkJYb0d2bWlKN1lrRTRP... Meeting ID: 976 8581 9574 Passcode: 216931
1:00pm - RH 306 - Harmonic Analysis Joris Roos - (UMass Lowell) Spherical maximal functions and fractal dimensions of dilation sets This talk is about maximal averages on spheres in two and higher-dimensional Euclidean space. This is a classic topic in harmonic analysis originating in questions on differentiability properties of functions. We consider maximal spherical averages with a supremum taken over a given dilation set. It turns out that the sharp Lp improving properties of such operators are closely related to fractal dimensions of the dilation set such as the Minkowski and Assouad dimensions. This leads to a surprising characterization of the closed convex sets which can occur as closure of the sharp Lp improving region of such a maximal operator. This is joint work with Andreas Seeger. If time allows we will also mention recent work on the Heisenberg group and related work in progress.

Fri Oct 13, 2023
1:00pm - MSTB 124 - Graduate Seminar Chris Davis - (UCI) Quiz writing We'll talk about writing and grading quizzes, with special focus on what can be done to try to make grading quizzes less painful.