Nonlinear boundary conditions Boundary conditions 22 p-Laplacian 18 Blow-up 12 Nonlinear equations 12 Numerical approximations 10 Problem solving 10 Variational problems 10 Asymptotic behaviour 8 Blow up 8 Elliptic systems 8 Eigenvalue problems 6 Eigenvalues and eigenfunctions 6 Elliptic equations 6 Mathematical models 6 Numerical blow-up 6 Resonance 6 Sobolev trace constants 6 Sobolev trace embedding 6 Topological methods 6 Bessel functions 4 Boundary value problems 4 Critical exponents 4 Differential equations 4 Fast diffusion equation 4 Global existence 4 Heat equation 4 Mathematical operators 4 Nonlinear diffusion 4 Nonlinear elliptic problems 4