A. Gritsans and F. Sadyrbaev. Nonlinear spectra for two-parameter eigenvalue problems |
Eigenvalue problems of the form $x'' = -\lambda f(x) + \mu g(x),$
$\quad (i),$ $x(0) = 0, \; x(1) = 0,$ $\quad (ii)$ are
considered. We are looking for $(\lambda, \mu)$ such that the
problem $(i), (ii)$ has a nontrivial solution. This problem
generalizes the famous Fu\v{c}ik problem for piece-wise linear
equations. In order to show that nonlinear Fu\v{c}ik spectra may
differ essentially from the classical ones, we consider functions
$f(x)$ and $g(x)$ such that they are piece-wise linear and the
first zero functions $t_1$ and $\tau_1$ can be computed
explicitly. Then it is possible to construct explicitly the
respective Fu\v{c}ik like spectra. |