H. L. Wietsma

collaborators

2 papers

math.FA2014

Antitonicity of the inverse for selfadjoint matrices, operators, and relations

J. Behrndt, S. Hassi, H. S. V. de Snoo +1

Let $H_{1}$ and $H_{2}$ be selfadjoint operators or relations (multivalued operators) acting on a separable Hilbert space and assume that the inequality $H_{1} \leq H_{2}$ holds. Then the…

math.FA2013

Products of generalized Nevanlinna functions with symmetric rational functions

S. Hassi, H. L. Wietsma

New classes of generalized Nevanlinna functions, which under multiplication with an arbitrary fixed symmetric rational function remain generalized Nevanlinna functions, are introdu…