4 papers
On the domains of Bessel operators
Jan Dereziński, Vladimir Georgescu
We consider the Schrödinger operator on the halfline with the potential , often called the Bessel operator. We assume that is complex. We study the do…
On the derivatives of the Heun functions
G. Filipuk, A. Ishkhanyan, J. Dereziński
The Heun functions satisfy linear ordinary differential equations of second order with certain singularities in the complex plane. The first order derivatives of the Heun functions…
Group-theoretical origin of symmetries of hypergeometric class equations and functions
Jan Dereziński
We show that properties of hypergeometric class equations and functions become transparent if we derive them from appropriate 2nd order differential equations with constant coeffic…
Quantum massless field in 1+1 dimensions
Jan Derezi{ń}ski, Krzysztof A. Meissner
We present a construction of the algebra of operators and the Hilbert space for a quantum massless field in 1+1 dimensions.