This talk introduces the article “Volume Estimates on the Critical Sets of Solutions to Elliptic PDEs” by Aaron Naber and Daniele Valtorta (https://onlinelibrary.wiley.com/doi/abs/10.1002/cpa.21708)
The talk focuses on Sections 2 and 3, with a sketch of Section 4.
Keywords: elliptic theory, critical set, Minkowski estimate, Almgren frequency