A description is given of methods that have been used to analyze the spectrum of non-self-
adjoint differential operators, emphasizing the differences from the self-adjoint theory. It …

We study singular left-definite Sturm–Liouville problems with an indefinite weight function.
The existence of eigenvalues is established based on the existence of eigenvalues of …

We introduce the concept of essential numerical range W e (T) for unbounded Hilbert space
operators T and study its fundamental properties including possible equivalent …

A new technique is presented which gives conditions under which perturbations of certain
base potentials are uniquely determined from the location of eigenvalues and resonances in …

We discuss realizations of L:=-∂ _x^ 2+ V (x) L:=-∂ x 2+ V (x) as closed operators on L^ 2 a,
b L 2 a, b, where V is complex, locally integrable and may have an arbitrary behavior at …

Spectral problems with band-gap spectral structure arise in numerous applications,
including the study of crystalline structure and the determination of transmitted frequencies …

We consider a Schroedinger equation on an exterior domain in the case where the potential,
which may be complex valued, has a limit at infinity. Associated with the problem is a …

We study spatial and spatio-temporal pattern formation emergent from reaction–diffusion–
advection systems formed by considering reaction–diffusion systems coupled to prescribed …

Titchmarsh–Sims–Weyl Theory for Complex Hamiltonian Systems Page 1
TITCHMARSH±SIMS±WEYL THEORY FOR COMPLEX HAMILTONIAN SYSTEMS BM …

This paper is concerned with Friedrichs extensions for a class of Hamiltonian systems. The
non-symmetric problems are usually complicated and have unexpected properties. Here …