We investigate the behaviour of a sequence ${\lambda }_s$, s = 1,2,..., of eigenvalues of the Dirichlet problem for the p-Laplacian in the domains ${\Omega }_s$, s = 1,2,..., obtained by removing from a given domain Ω a set $E_s$ whose diameter vanishes when s → ∞. We estimate the deviation of ${\lambda }_s$ from the eigenvalue of the limit problem. For the derivation of our results we construct an appropriate asymptotic expansion for the sequence of solutions of the original eigenvalue problem.

We give necessary and sufficient conditions for the formal power series solutions to the initial value problem for the Burgers equation ${\partial }_{t}u-{\partial }_x²u={\partial }_x\left(u²\right)$ to be convergent or Borel summable.

We study the behaviour of the steady-state voltage potential in a material composed of a two-dimensional object surrounded by a rough thin layer and embedded in an ambient medium. The roughness of the layer is supposed to be εα–periodic, ε being the magnitude of the mean thickness of the layer, and α a positive parameter describing the degree of roughness. For ε tending to zero, we determine the appropriate boundary layer correctors which lead to approximate transmission conditions equivalent to...

This article is concerned with the nonlinear singular perturbation problem due to small diffusivity in nonlinear evolution equations of Chaffee-Infante type. The boundary layer appearing at the boundary of the domain is fully described by a corrector which is “explicitly" constructed. This corrector allows us to obtain convergence in Sobolev spaces up to the boundary.

Asymptotic formulae for solutions to boundary value problems for linear and quasilinear elliptic equations and systems near a boundary point are discussed. The boundary is not necessarily smooth. The main ingredient of the proof is a spectral splitting and reduction of the original problem to a finite-dimensional dynamical system. The linear version of the corresponding abstract asymptotic theory is presented in our new book “Differential equations with operator coefficients”, Springer, 1999.