M. Langer,
A general HELP inequality connected with symmetric operators,
Proc. R. Soc. Lond. Ser. A Math. Phys. Eng. Sci. 462 (2006), 587–606
Abstract:
In this paper, a general HELP (Hardy–Everitt–Littlewood–Pólya)
inequality is considered which is connected with a symmetric operator in a Hilbert space and
abstract boundary mappings. A criterion for the validity of such an inequality in
terms of the abstract Titchmarsh–Weyl function is proved and applied to
Sturm–Liouville operators, difference operators, a Hamiltonian system and a
block operator matrix.