A remark on the discriminant of Hill's equation and Herglotz functions
arXiv:1401.1662 · doi:10.1007/s00013-014-0612-x
Abstract
We establish a link between the basic properties of the discriminant of periodic second-order differential equations and an elementary analysis of Herglotz functions. Some generalizations are presented using the language of self-adjoint extensions.
5 pages. This is preliminary version. The final version is accepted in Archiv der Mathematik (Basel) published by Birkhaeuser