Kelvin-Stuart vortices are classical mixing layer flows with many applications in fluid
mechanics, plasma physics and astrophysics. We prove that the whole family of Kelvin …

The abstract theory of boundary triples is applied to the classical Jacobi differential operator
and its powers in order to obtain the Weyl m-function for several self-adjoint extensions with …

We set out to build a framework for self-adjoint extension theory for powers of the Jacobi
differential operator that does not make use of classical deficiency elements. Instead, we rely …

We use a model operator approach and the spectral theorem for self-adjoint operators in a
Hilbert space to derive the basic results of abstract left-definite theory in a straightforward …

We present a fast Galerkin spectral method to solve logarithmic singular equations on
segments. The proposed method uses weighted first-kind Chebyshev polynomials …

In the early 2000s, Littlejohn and Wellman developed so-called n th left-definite theory.
Namely, they fully determined the 'left-definite domains' and spectral properties of powers of …

If A is a self-adjoint operator that is bounded below in a Hilbert space H, Littlejohn and
Wellman (J Diff Equ 181 (2): 280–339, 2002) showed that, for each r> 0, there exists a …

We propose, analyze, and implement interpolatory approximations and Filon-type cubature
for efficient and accurate evaluation of a class of wideband generalized Fourier integrals on …

We set out to build a framework for self-adjoint extension theory when the operators are
powers of classical Sturm–Liouville operators. This is done by analyzing the structures of …

Abstract In 2002, Littlejohn and Wellman developed a celebrated general left-definite theory
for semi-bounded self-adjoint operators with many applications to differential operators. The …