5 papers
Basic representation theorems of forms
Zoltán Sebestyén, Zsigmond Tarcsay
We study maximal representations of nonnegative sesquilinear forms in real or complex Hilbert spaces, that are not necessarily closed or even closable. We associate positive self-a…
On the adjoint of Hilbert space operators
Zoltán Sebestyén, Zsigmond Tarcsay
In general, it is a non trivial task to determine the adjoint of an unbounded operator acting between two Hilbert spaces. We provide necessary and sufficient conditions f…
On operators which are adjoint to each other
Dan Popovici, Zoltan Sebestyen
Given two linear operators and acting between Hilbert spaces and , respectively and which satisfy the relation \begin…
Factorizations of Linear Relations
Dan Popovici, Zoltan Sebestyen
Given two linear relations and we characterize the existence of a linear relation (operator) such that , respectively These factorizatio…
A canonical decomposition for linear operators and linear relations
S. Hassi, Z. Sebestyén, H. S. V. de Snoo +1
An arbitrary linear relation (multivalued operator) acting from one Hilbert space to another Hilbert space is shown to be the sum of a closable operator and a singular relation who…