This book provides an introduction to the most recent developments in the theory and
practice of direct and inverse Sturm-Liouville problems on finite and infinite intervals. A …

In the present review, we deal with the recently introduced method of spectral parameter
power series (SPPS) and show how its application leads to an explicit form of the …

We systematically develop Weyl-Titchmarsh theory for singular differential operators on
arbitrary intervals $(a, b)\subseteq\mathbb {R} $ associated with rather general differential …

We develop Weyl–Titchmarsh theory for Schrödinger operators with strongly singular
potentials such as perturbed spherical Schrödinger operators (also known as Bessel …

This textbook provides a thorough overview of mathematical physics, highlighting classical
topics as well as recent developments. Readers will be introduced to a variety of methods …

We extend the classical boundary values (0.1) g (a)=− W (ua (λ 0,⋅), g)(a)= lim x↓ a⁡ g (x)
u ˆ a (λ 0, x), g [1](a)=(pg′)(a)= W (u ˆ a (λ 0,⋅), g)(a)= lim x↓ a⁡ g (x)− g (a) u ˆ a (λ 0, x) ua …

A new representation for a regular solution of the perturbed Bessel equation of the form is
obtained. The solution is represented as a Neumann series of Bessel functions uniformly …

A spectral parameter power series (SPPS) representation for regular solutions of singular
Bessel type Sturm–Liouville equations with complex coefficients is obtained as well as an …

We discuss direct and inverse spectral theory for the isospectral problem of the
dispersionless Camassa–Holm equation, where the weight is allowed to be a finite signed …

We explore the connections between singular Weyl–Titchmarsh theory and the single and
double commutation methods. In particular, we compute the singular Weyl function of the …