AMONG those who are trying to acquire a general acquaintance with Schrödinger's wave-mechanics there must be many who find their mathematical equipment insufficient to follow his first great ...

Both existence and non-existence results for principal eigenvalues of an elliptic operator with indefinite weight function have been proved. The existence of a continuous family of principal ...

This is a preview. Log in through your library . Abstract One of the most common methods for calculating the eigenvalues of the Sturm-Liouville problem such as (p ψ')' + (λ r - q) ψ = 0 is to ...