Events for 04/11/2023 from all calendars

Several Complex Variables Seminar

Time: 12:50PM - 1:50PM

Location: Zoom

Speaker: Achinta Kumar Nandi, Oklahoma State University

Title: On perturbations of singular complex analytic hypervarieties

Abstract: In this talk, we shall discuss an extension and higher dimensional generalization of a result by Lyubich and Peters on perturbations of singular Riemann Surfaces. We will further investigate its higher codimension analog.

Nonlinear Partial Differential Equations

Time: 3:00PM - 4:00PM

Location: ZOOM

Speaker: Xu Yuan, Chinese University of Hong Kong

Title: Construction of multi-solitons for the energy-critical wave equation

Abstract: We will review some results on the construction and interaction of solitary waves for the energy-critical focusing wave equation. After discussing briefly the well-known conjecture of soliton resolution, we will present recent results of the existence of multi-solitary waves in the case of weak interactions.

Maxson Lecture Series

Time: 4:00PM - 5:00PM

Location: BLOC 117

Speaker: Kannan Soundararajan, Stanford University

Title: Covering integers using quadratic forms

Abstract: How large must \Delta be so that we can cover a substantial proportion of the integers below X using the binary quadratic forms x^2 +dy^2 with d below \Delta? Problems involving representations by binary quadratic forms have a long history, going back to Fermat. The particular problem mentioned here was recently considered by Hansen and Vaughan, and Diao. In ongoing work with Ben Green, we resolve this problem, and identify a sharp phase transition: If \Delta is below (log X)^{log 2-\epsilon} then zero percent of the integers below X are represented, whereas if \Delta is above (log X)^{log 2 +\epsilon} then 100 percent of the integers below X are represented. I will give a gentle introduction to some of the ideas involved.