@article{MTMT:34751048,
	title = {Reduction of positive self-adjoint extensions},
	url = {https://m2.mtmt.hu/api/publication/34751048},
	author = {Tarcsay, Zsigmond and Sebestyén, Zoltán},
	doi = {10.7494/OpMath.2024.44.3.425},
	journal-iso = {OPUSC MATHEMATICA},
	journal = {OPUSCULA MATHEMATICA},
	volume = {44},
	unique-id = {34751048},
	issn = {1232-9274},
	year = {2024},
	pages = {425-438},
	orcid-numbers = {Tarcsay, Zsigmond/0000-0001-8102-5055}
}

@article{MTMT:33766588,
	title = {Extensions of positive symmetric operators and Krein's uniqueness criteria},
	url = {https://m2.mtmt.hu/api/publication/33766588},
	author = {Sebestyén, Zoltán and Tarcsay, Zsigmond},
	doi = {10.1080/03081087.2023.2196610},
	journal-iso = {LINEAR MULTILINEAR A},
	journal = {LINEAR AND MULTILINEAR ALGEBRA},
	unique-id = {33766588},
	issn = {0308-1087},
	year = {2023},
	eissn = {1563-5139},
	orcid-numbers = {Tarcsay, Zsigmond/0000-0001-8102-5055}
}

@article{MTMT:32080890,
	title = {On the Krein-von Neumann and Friedrichs extension of positive operators},
	url = {https://m2.mtmt.hu/api/publication/32080890},
	author = {Sebestyén, Zoltán and Tarcsay, Zsigmond},
	journal-iso = {ACTA WASA},
	journal = {ACTA WASAENSIA},
	volume = {462},
	unique-id = {32080890},
	issn = {0355-2667},
	year = {2021},
	pages = {165-178},
	orcid-numbers = {Tarcsay, Zsigmond/0000-0001-8102-5055}
}

@article{MTMT:31840162,
	title = {Canonical Graph Contractions of Linear Relations on Hilbert Spaces},
	url = {https://m2.mtmt.hu/api/publication/31840162},
	author = {Tarcsay, Zsigmond and Sebestyén, Zoltán},
	doi = {10.1007/s11785-020-01066-3},
	journal-iso = {COMPLEX ANAL OPER TH},
	journal = {COMPLEX ANALYSIS AND OPERATOR THEORY},
	volume = {15},
	unique-id = {31840162},
	issn = {1661-8254},
	year = {2021},
	eissn = {1661-8262},
	orcid-numbers = {Tarcsay, Zsigmond/0000-0001-8102-5055}
}

@article{MTMT:31300976,
	title = {Range-kernel characterizations of operators which are adjoint of each other},
	url = {https://m2.mtmt.hu/api/publication/31300976},
	author = {Tarcsay, Zsigmond and Sebestyén, Zoltán},
	doi = {10.1007/s43036-020-00068-4},
	journal-iso = {ADV OPERAT THEORY},
	journal = {ADVANCES IN OPERATOR THEORY},
	volume = {5},
	unique-id = {31300976},
	year = {2020},
	eissn = {2538-225X},
	pages = {1026-1038},
	orcid-numbers = {Tarcsay, Zsigmond/0000-0001-8102-5055}
}

@article{MTMT:30446535,
	title = {On the adjoint of Hilbert space operators},
	url = {https://m2.mtmt.hu/api/publication/30446535},
	author = {Sebestyén, Zoltán and Tarcsay, Zsigmond},
	doi = {10.1080/03081087.2018.1430120},
	journal-iso = {LINEAR MULTILINEAR A},
	journal = {LINEAR AND MULTILINEAR ALGEBRA},
	volume = {67},
	unique-id = {30446535},
	issn = {0308-1087},
	abstract = {In general, it is a non-trivial task to determine the adjoint S* of an unbounded operator S acting between two Hilbert spaces. We provide necessary and sufficient conditions for a given operator T to be identical with S*. In our considerations, a central role is played by the operator matrix M-S,M-T = (I -T S I). Our approach has several consequences such as characterizations of closed, normal, skew- and selfadjoint, unitary and orthogonal projection operators in real or complex Hilbert spaces. We also give a self-contained proof of the fact that T*T always has a positive selfadjoint extension.},
	keywords = {Positive operator; selfadjoint operator; adjoint; closed operator},
	year = {2019},
	eissn = {1563-5139},
	pages = {625-645},
	orcid-numbers = {Tarcsay, Zsigmond/0000-0001-8102-5055}
}

@article{MTMT:30789347,
	title = {A characterization of positive normal functionals on the full operator algebra},
	url = {https://m2.mtmt.hu/api/publication/30789347},
	author = {Sebestyén, Zoltán and Tarcsay, Zsigmond and Titkos, Tamás},
	doi = {10.1007/978-3-319-75996-8_24},
	journal-iso = {OPER THER ADV APPL},
	journal = {OPERATOR THEORY: ADVANCES AND APPLICATIONS},
	volume = {268},
	unique-id = {30789347},
	issn = {0255-0156},
	abstract = {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 operator algebra B(H) is normal. We also characterize those functionals defined on the left ideal of finite rank operators that have a normal extension. © 2018, Springer International Publishing AG, part of Springer Nature.},
	keywords = {TRACE; Krein-von Neumann extension; Normal functionals},
	year = {2018},
	eissn = {2296-4878},
	pages = {443-447},
	orcid-numbers = {Tarcsay, Zsigmond/0000-0001-8102-5055}
}

@article{MTMT:30349889,
	title = {Lebesgue type decompositions for linear relations and Ando's uniqueness criterion},
	url = {https://m2.mtmt.hu/api/publication/30349889},
	author = {Hassi, S. and Sebestyén, Zoltán and De, Snoo H.},
	doi = {10.14232/actasm-018-757-0},
	journal-iso = {ACTA SCI MATH (SZEGED)},
	journal = {ACTA SCIENTIARUM MATHEMATICARUM (SZEGED)},
	volume = {84},
	unique-id = {30349889},
	issn = {0001-6969},
	year = {2018},
	pages = {465-507}
}

@article{MTMT:3293570,
	title = {On the square root of a positive selfadjoint operator},
	url = {https://m2.mtmt.hu/api/publication/3293570},
	author = {Sebestyén, Zoltán and Tarcsay, Zsigmond},
	doi = {10.1007/s10998-017-0192-1},
	journal-iso = {PERIOD MATH HUNG},
	journal = {PERIODICA MATHEMATICA HUNGARICA},
	volume = {75},
	unique-id = {3293570},
	issn = {0031-5303},
	abstract = {We provide a short, elementary proof of the existence and uniqueness of the square root in the context of unbounded positive selfadjoint operators on real or complex Hilbert spaces.},
	keywords = {SQUARE ROOT; Positive operator; selfadjoint operator; Unbounded operator},
	year = {2017},
	eissn = {1588-2829},
	pages = {268-272},
	orcid-numbers = {Tarcsay, Zsigmond/0000-0001-8102-5055}
}

@article{MTMT:3084669,
	title = {Adjoint of sums and products of operators in Hilbert spaces},
	url = {https://m2.mtmt.hu/api/publication/3084669},
	author = {Sebestyén, Zoltán and Tarcsay, Zsigmond},
	doi = {10.14232/actasm-015-809-3},
	journal-iso = {ACTA SCI MATH (SZEGED)},
	journal = {ACTA SCIENTIARUM MATHEMATICARUM (SZEGED)},
	volume = {82},
	unique-id = {3084669},
	issn = {0001-6969},
	year = {2016},
	pages = {175-191},
	orcid-numbers = {Tarcsay, Zsigmond/0000-0001-8102-5055}
}