Shock Formation for the Einstein–Euler System

In this talk, I hope to describe elements of proving a certain stable singularity formation result for the Einstein-Euler system, which is the topic of work in progress with Jonathan Luk. I'll first describe some motivating phenomena. Then, I will describe some of the main mathematical difficulties which present themselves when studying multidimensional shocks and why it is appropriate to call this a shock formation result. Finally, I will try to describe some of the main ideas that go into mathematically understanding shock formation, and the main difficulty in the case of Einstein--Euler.