Refining eigenvalue estimates for a string with a singular weight (Q2064220)

In this paper, the author investigates eigenvalue estimates. That is, the author proves that the eigenvalues of the operator pencil \(A(\lambda)\), where \(A(\lambda) \equiv L-\lambda V\), \(L\equiv-y^{\prime\prime}+q(x)y\), satisfy the estimate \(\vert \lambda_{n}\vert \geq Cn\) \ for all \(n\in\mathbb{N}\), where \(C\) is a constant independent of the number \(n\).