Abstract:
In the paper we consider two-parameter spectral problem
\begin{equation*}
\begin{cases}
{\lambda _{1} K_{r1} \varphi _{r} +\lambda _{2} K_{r2} \varphi _{r} =\varphi _{r} ,\quad \varphi _{r} \in H_{r} }, \\ {r=1,2}
\end{cases}
\end{equation*}
with compact self-adjoint operators in Hilbert space under left definiteness condition. The analog of the variational principle was obtained for the two-parameter spectral problem.