On the Morse-Sard property and level sets of $W^{n,1}$ Sobolev functions on ${\mathbb{R}}^n$

Jean Bourgain, Mikhail V. Korobkov, Jan Kristensen

We establish Luzin N and Morse--Sard properties for functions from the Sobolev space $W^{n,1}({\mathbb{R}}^n)$. Using these results we prove that almost all level sets are finite…