On the spectrum of a nontypical eigenvalue problem
Mihai Mihăilescu, Denisa Stancu‐Dumitru · Electronic journal of qualitative theory of differential equations · 2018
We study a nontypical eigenvalue problem in a bounded domain from the Euclidian space $\mathbb{R}^2$ subject to the homogeneous Dirichlet boundary condition. We show that the spectrum of the problem contains two distinct intervals separated by an interval where there are no other eigenvalues.