EN
CONTENTS
Preliminaries........................................................................................................ 5
1. Auxiliary results......................................................................................................... 13
2. The second order equations.................................................................................. 14
3. Some properties of Sobolev and Besov spaces................................................ 20
4. Classes $Λ^α(G, H)$, 0 < a ≤ 1............................................................................ 21
5. The case of Lipschitz characteristics................................................................... 26
6. Existence of second partial derivatives and its consequences...................... 29
7. Local boundedness of the Jacobian.................................................................... 33
8. Smoothness.............................................................................................................. 41
References.................................................................................................................... 44