Department of Mathematics, Purdue University
PDE Seminar

Spring 2026

Talks in Spring 2025 will take place at 1:30-2:20pm, Thursday, SCHM 114. If you have any questions about a particular seminar, please contact the organizers at: wang2482@purdue.edu


Date SPEAKER Host
January 22 No Seminar
TITLE :
ABSTRACT:
January 29 Changyou Wang, Purdue University
TITLE : Heat flow of harmonic maps into CAT(0)-metric spaces
ABSTRACT: In this talk, we will describe a new approach to construct the existence of a unique suitable weak solution of the heat flow of harmonic maps into CAT(0)-metric space. The target space is the non-smooth version of nonpositively curved smooth manifolds in the sense of Alexandrov. The approach is variational and based on the minimization of a Weighted Energy Dissipation (WED) energy functional, which can be viewed as an elliptic regularization of parabolic problems proposed by De Giorgi back in 1990’s. By introducing a parabolic frequency function in the spirit of Frederick Almgren, we are able to show the existence of a unique global weak solution of the heat flow into a CAT(0) space that is Lipschitz in spatial variable and halfH\”older continuous in time variable. As a byproduct, this provides a new proof of the celebrated Eells-Sampson theorem on heat flow into non-positively curved manifolds. This is a joint work with F. Lin, A. Segatti, and Y. Sire.
Wang
February 5 Nick Gismondi, Purdue University
TITLE: Integrable Weak Solutions of Stationary Active Scalar Equations
ABSTRACT: In this talk, I will discuss the construction of nontrivial integrable weak solutions for certain classes of stationary active scalar equations using a convex integration framework. We focus in particular on stationary active scalar equations with non-odd drift, as well as the stationary surface quasi-geostrophic equation. A central feature of the scheme is measuring the error in a negative-regularity homogeneous Sobolev norm, which enables the use of generic intermittent building blocks and allows us to consider arbitrary dissipation exponents. This talk is based on joint work with Alexandru Radu.
Wang
February 12 Howen Chuah, Purdue University
TITLE : On a Nonlinear Model for Long Range Segregation
ABSTRACT : We consider a system of fully nonlinear elliptic equations, depending on a small parameter, that models long-range segregation in population dynamics. The diffusion is governed by the negative nonlinear Pucci operator. We establish the existence of solutions and prove convergence, as the parameter goes to zero, to a free boundary problem. In the limt, high competition forces the species to segregate at a positive distance. Geometric properties of the free boundaries will be discussed, including directions for future research. This talk is based on joint work with Professors Monica Torres and Stefania Patrizi.
Torres
February 19 Raghav Venkatraman, University of Utah
TITLE:
ABSTRACT :
Yip
February 26 Iassc Harris, Purdue University
TITLE:
ABSTRACT:
Wang
March 5 Peter Morfe, PSU
TITLE:
ABSTRACT:
Yip
March 12 Mathew George, Purdue University

Wang
March 19 (Spring Break, No Seminar)

March 26 Monica Torres, Purdue University
TITLE:
ABSTRACT :
Wang
April 2 Antonios Zitridis, University of Michigan
TITLE:
ABSTRACT :
Han
April 9 Christopher Irving, Georgetown University

TITLE:
ABSTRACT :
Torres
April 16 Agnid Banerjee, ASU
TITLE:
ABSTRACT :
Wang
April 23 Roman Shvydkoy, UIC
TITLE:
ABSTRACT :
Novack
April 30 Anuj Kumar, UC Davis
TITLE:
ABSTRACT :
Novack
May 7 Junyuan Fang, UTK
TITLE:
ABSTRACT :
Wang