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# Casey Rodriguez, MIT – Special Colloquium

## September 17, 2020 @ 5:00 pm - 6:00 pm

**Zoom Link:** https://unc.zoom.us/j/96995841746

Virtual tea time starts at 4:30 pm. Talk begins at 5:00 pm.

**Title:** The Radiative Uniqueness Conjecture for Bubbling Wave Maps

**Abstract:** We will discuss the finite time breakdown of solutions to a canonical example of a geometric wave equation; energy critical wave maps. Breakthrough works of Krieger-Schlag–Tataru, Rodnianski– Sterbenz and Rapha ̈el–Rodnianski produced examples of wave maps that develop singularities in finite time. These solutions break down by concentrating energy at a point in space (via bubbling a harmonic map) but have a regular limit, away from the singular point, as time approaches the final time of existence. The regular limit is referred to as the radiation. This mechanism of breakdown occurs in many other PDE including energy critical wave equations, Schro ̈dinger maps and Yang-Mills equations. A basic question is the following:

• Can we give a precise description of all bubbling singularities for wave maps with the goal of finding the natural unique continuation of such solutions past the singularity?

In this talk, we will discuss recent work (joint with J. Jendrej and A. Lawrie) which is the first to directly and explicitly connect the radiative component to the bubbling dynamics by constructing and classifying bubbling solutions with a simple form of prescribed radiation. Our results serve as an important first step in formulating and proving the following Radiative Uniqueness Conjecture for a large class of wave maps: every bubbling solution is uniquely characterized by it’s radiation, and thus, every bubbling solution can be uniquely continued past blow-up time while conserving energy.