### PDE models for collective dynamics

- Series
- Research Horizons Seminar
- Time
- Wednesday, October 19, 2016 - 12:05 for 1 hour (actually 50 minutes)
- Location
- Skiles 006
- Speaker
- Prof. Yao Yao – Department of Mathematics, Georgia Institute of Technology – yaoyao@math.gatech.edu

**Please Note:** Refreshments will be provided before the seminar.

Collective behavior can be seen in many animal species, such as flocking birds, herding mammals, and swarming bacteria. In the continuum limit, these phenomena can be modeled by nonlocal PDEs. In this talk, after discussing some PDE models for collective dynamics, I will focus on the analysis of the Keller-Segel equation, which models bacterial chemotaxis. Mathematically, this equation exhibits an intriguing "critical mass phenomenon": namely, solutions exist globally in time for all initial data whose mass is below some certain constant, whereas finite-time blow-up always happen if the initial mass is above this constant. I will introduce some useful analysis tools that lead to this result, and discuss some active areas of current research.