TY  - JOUR
AU  - Sebestyén, Zoltán
AU  - Tarcsay, Zsigmond
TI  - Characterizations of essentially self-adjoint and skew-adjoint operators
JF  - STUDIA SCIENTIARUM MATHEMATICARUM HUNGARICA
J2  - STUD SCI MATH HUNG
VL  - 52
PY  - 2015
IS  - 3
SP  - 371
EP  - 385
PG  - 15
SN  - 0081-6906
DO  - 10.1556/012.2015.52.3.1300
UR  - https://m2.mtmt.hu/api/publication/2969008
ID  - 2969008
N1  - Cited By :8            
            Export Date: 7 September 2022
AB  - An extension of von Neumann's characterization of essentially selfadjoint operators is given among not necessarily densely defined symmetric operators which are assumed to be closable. Our arguments are of algebraic nature and follow the idea of [1]. © 2015 Akadémiai Kiadó, Budapest.
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Popovici, Dan
AU  - Sebestyén, Zoltán
TI  - On operators which are adjoint to each other
JF  - ACTA SCIENTIARUM MATHEMATICARUM (SZEGED)
J2  - ACTA SCI MATH (SZEGED)
VL  - 80
PY  - 2014
IS  - 1-2
SP  - 175
EP  - 194
PG  - 20
SN  - 0001-6969
DO  - 10.14232/actasm-012-857-7
UR  - https://m2.mtmt.hu/api/publication/3079525
ID  - 3079525
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Sebestyén, Zoltán
AU  - Tarcsay, Zsigmond
TI  - CHARACTERIZATIONS OF SELFADJOINT OPERATORS
JF  - STUDIA SCIENTIARUM MATHEMATICARUM HUNGARICA
J2  - STUD SCI MATH HUNG
VL  - 50
PY  - 2013
IS  - 4
SP  - 423
EP  - 435
PG  - 13
SN  - 0081-6906
DO  - 10.1556/SScMath.50.2013.4.1252
UR  - https://m2.mtmt.hu/api/publication/2541922
ID  - 2541922
AB  - The purpose of this paper is to revise von Neumann's characterizations of selfadjoint operators among symmetric ones. In fact, we do not assume that the underlying Hilbert space is complex, nor that the corresponding operator is densely defined, moreover, that it is closed. Following Arens, we employ algebraic arguments instead of the geometric approach of von Neumann using the Cayley transform.
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Sebestyén, Zoltán
AU  - Tarcsay, Zsigmond
TI  - T∗T always has a positive selfadjoint extension
JF  - ACTA MATHEMATICA HUNGARICA
J2  - ACTA MATH HUNG
VL  - 135
PY  - 2012
IS  - 1-2
SP  - 116
EP  - 129
PG  - 14
SN  - 0236-5294
DO  - 10.1007/s10474-011-0154-7
UR  - https://m2.mtmt.hu/api/publication/2433949
ID  - 2433949
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Sebestyén, Zoltán
AU  - Stochel, Jan
TI  - Restrictions of positive selfadjoint operators
JF  - ACTA SCIENTIARUM MATHEMATICARUM (SZEGED)
J2  - ACTA SCI MATH (SZEGED)
VL  - 55
PY  - 1991
IS  - 1-2
SP  - 149
EP  - 154
PG  - 6
SN  - 0001-6969
UR  - https://m2.mtmt.hu/api/publication/3079745
ID  - 3079745
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Sebestyén, Zoltán
TI  - ON RANGES OF ADJOINT OPERATORS IN HILBERT-SPACE
JF  - ACTA SCIENTIARUM MATHEMATICARUM (SZEGED)
J2  - ACTA SCI MATH (SZEGED)
VL  - 46
PY  - 1983
IS  - 1-4
SP  - 295
EP  - 298
PG  - 4
SN  - 0001-6969
UR  - https://m2.mtmt.hu/api/publication/3066108
ID  - 3066108
LA  - English
DB  - MTMT
ER  -