Sharp Spectral Inequalities for Fourth Order Differential Operators on Semi-Axis

Improved sharp spectral inequalities for Schrödinger operators on the semi-axis

“…Our Theorem 2 shows that such an approach cannot yield a sharp inequality if the potential supports more than one eigenvalue. Recently the same variation of the commutation method has been applied to fourth-order operators on the semi-axis [20]. In all of theses applications, the applied method is more precisely known as the single commutation method.…”