4 papers
Canonical graph contractions of linear relations on Hilbert spaces
Zsigmond Tarcsay, Zoltán Sebestyén
Given a closed linear relation between two Hilbert spaces and , the corresponding first and second coordinate projections and are both line…
Range-kernel characterizations of operators which are adjoint of each other
Zoltán Sebestyén, Zsigmond Tarcsay
We provide necessary and sufficient conditions for a pair of Hilbert space operators in order that they satisfy and . As a main result we establish an improvem…
Lebesgue type decompositions for linear relations and Ando's uniqueness criterion
Seppo Hassi, Zoltán Sebestyén, Henk de Snoo
A linear relation, i.e., a multivalued operator from a Hilbert space to a Hilbert space has Lebesgue type decompositions , where…
A characterization of positive normal functionals on the full operator algebra
Zoltán Sebestyén, Zsigmond Tarcsay, Tamás Titkos
Using the recent theory of Krein--von Neumann extensions for positive functionals we present several simple criteria to decide whether a given positive functional on the full opera…