Mixed Boundary Value Problems for Nonlinear Elliptic Systems with p‐Structure in Polyhedral Domains

The nonlinear elliptic system is investigated on a non‐smooth domain. Mixed boundary value conditions are given. The left‐hand side of the system has p‐structure (e.g., it is the p‐Laplacian and 1 < p < ∞). Global regularity results of u and |∇u|^p/2 in fractional order Sobolev spaces are proven.