Solutions of some nonlinear elliptic problems with perturbation terms of arbitrary growth (Q1433442)

The authors consider the following elliptic boundary value problem \[ \begin{cases} -\Delta u= f(x,u)+\mu g(x, u)\quad &\text{in }\Omega,\\ u= 0\quad &\text{on }\partial\Omega,\end{cases}\tag{1} \] where \(\Omega\) is a bounded domain in \(\mathbb{R}^N\) with smooth boundary \(\partial\Omega\), \(f,g: \overline\Omega\times\mathbb{R}\to \mathbb{R}\), \(f(x,0)= g(x,0)= 0\), and \(\mu\) is a real parameter. They prove existence and multiplicity solutions for (1). To this end the authors use variational approach.