Asymptotic distribution of eigenvalues of differential equations

In this paper is studied the asymptotic distribution of eigenvalues of the equation $Au=\lambda Bu$, considered in a bounded domain $G\subseteq\mathbf R^n$ with zero boundary conditions. Here $A$ and $B$ are differential operators. Under particular conditions on $A$ and $B$, the asymptotic behavior of the eigenvalues is determined as they tend to $\pm\infty$.
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