TY  - JOUR
AU  - Matache, Valentin
TI  - When is a scaled contraction hypercyclic?
JF  - BOLLETTINO DELLA UNIONE MATEMATICA ITALIANA
J2  - BOLL UNIONE MAT ITAL
PY  - 2020
PG  - 17
SN  - 1972-6724
DO  - 10.1007/s40574-020-00260-7
UR  - https://m2.mtmt.hu/api/publication/31725389
ID  - 31725389
AB  - Hypercyclic operators are operators with dense orbits. A contraction cannot be hypercyclic since its orbits are bounded sets. Nevertheless, by multiplying a contraction with a scalar of absolute value larger than 1, the resulting scaled contraction can occasionally be a hypercyclic operator. In this paper, we investigate which Hilbert space contractions have that property and which don't. We introduce the set Lambda(T) of all scalars which produce a hypercyclic operator, by scaling the operator T, and determine Lambda(T) in various cases. New properties of hyperciclic operators are discovered in this process. For instance, it is proved that any connected component of the essential spectrum of a hypercyclic operator must meet the unit circle.
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - H, Bercovici
AU  - R G, Douglas
AU  - C, Foias
AU  - C, Pearcy
TI  - Confluent operator algebras and closability property
JF  - JOURNAL OF FUNCTIONAL ANALYSIS
J2  - J FUNCT ANAL
VL  - 258
PY  - 2010
SP  - 4122
EP  - 4153
PG  - 32
SN  - 0022-1236
DO  - 10.1016/j.jfa.2010.03.009
UR  - https://m2.mtmt.hu/api/publication/22281640
ID  - 22281640
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - M F, Gamal
TI  - On contractions with compact defects
JF  - JOURNAL OF MATHEMATICAL SCIENCES (NEW YORK)
J2  - J MATH SCI (NEW YORK)
VL  - 366
PY  - 2009
IS  - 4
SP  - 13
EP  - 41
PG  - 29
SN  - 1072-3374
DO  - 10.1007/s10958-010-9811-6
UR  - https://m2.mtmt.hu/api/publication/22281643
ID  - 22281643
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Gamal, M F
TI  - On contractions that are quasiaffine transforms of unilateral shifts
JF  - ACTA SCIENTIARUM MATHEMATICARUM (SZEGED)
J2  - ACTA SCI MATH (SZEGED)
VL  - 74
PY  - 2008
SP  - 757
EP  - 767
PG  - 11
SN  - 0001-6969
UR  - https://m2.mtmt.hu/api/publication/20790776
ID  - 20790776
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Kérchy, László
TI  - Shift-type invariant subspaces of contractions
JF  - JOURNAL OF FUNCTIONAL ANALYSIS
J2  - J FUNCT ANAL
VL  - 246
PY  - 2007
SP  - 281
EP  - 301
PG  - 21
SN  - 0022-1236
DO  - 10.1016/j.jfa.2007.01.011
UR  - https://m2.mtmt.hu/api/publication/1265041
ID  - 1265041
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Duggal, B P
AU  - Djordjevic, null
AU  - Kubrusly, C S
TI  - Hereditarily normaloid contractions
JF  - ACTA SCIENTIARUM MATHEMATICARUM (SZEGED)
J2  - ACTA SCI MATH (SZEGED)
VL  - 71
PY  - 2005
SP  - 337
EP  - 352
PG  - 16
SN  - 0001-6969
UR  - https://m2.mtmt.hu/api/publication/20134327
ID  - 20134327
LA  - English
DB  - MTMT
ER  - 

TY  - CHAP
AU  - Kerchy, L
ED  - Kerchy, L
ED  - Foias, C
ED  - Gohberg, I
ED  - Langer, H
TI  - On the hyperinvariant subspace problem for asymptotically nonvanishing contractions
T2  - OPERATOR THEORY : ADVANCES AND APPLICATIONS
PB  - Birkhäuser Publishing Ltd.
CY  - Basel
SN  - 3764366079
PB  - Birkhäuser Publishing Ltd.
PY  - 2001
SP  - 399
EP  - 422
PG  - 24
UR  - https://m2.mtmt.hu/api/publication/26883215
ID  - 26883215
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Mancera, C H
AU  - Paul, P J
TI  - Remarks, examples and spectral properties of generalized Toeplitz operators
JF  - ACTA SCIENTIARUM MATHEMATICARUM (SZEGED)
J2  - ACTA SCI MATH (SZEGED)
VL  - 66
PY  - 2000
SP  - 737
EP  - 753
PG  - 17
SN  - 0001-6969
UR  - https://m2.mtmt.hu/api/publication/20134420
ID  - 20134420
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Exner, G R
AU  - Jung, I B
TI  - Some multiplicities for contractions with Hilbert-Schmidt defect
JF  - OPERATOR THEORY: ADVANCES AND APPLICATIONS
J2  - OPER THER ADV APPL
VL  - 104
PY  - 1998
SP  - 113
EP  - 138
PG  - 26
SN  - 0255-0156
UR  - https://m2.mtmt.hu/api/publication/20134413
ID  - 20134413
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Kapustin, V V
TI  - Hyperreflexivity of contractions close to isometries
VL  - 174
PY  - 1996
SP  - 193
EP  - 203
PG  - 11
UR  - https://m2.mtmt.hu/api/publication/20134434
ID  - 20134434
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Kérchy, László
TI  - On the functional calculus of contractions with nonvanishing unitary symptotes
JF  - MICHIGAN MATHEMATICAL JOURNAL
J2  - MICH MATH J
VL  - 37
PY  - 1990
SP  - 323
EP  - 338
PG  - 16
SN  - 0026-2285
UR  - https://m2.mtmt.hu/api/publication/1049043
ID  - 1049043
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Kérchy, László
TI  - Isometric asymptotes of power bounded operators
JF  - INDIANA UNIVERSITY MATHEMATICS JOURNAL
J2  - INDIANA U MATH J
VL  - 38
PY  - 1989
SP  - 173
EP  - 188
PG  - 16
SN  - 0022-2518
DO  - 10.1512/iumj.1989.38.38008
UR  - https://m2.mtmt.hu/api/publication/1048794
ID  - 1048794
LA  - English
DB  - MTMT
ER  - 

TY  - BOOK
AU  - Beauzamy, B
TI  - Introduction to Operator Theory and Invariant Subspaces
PB  - North-Holland Publishing
CY  - Amsterdam
PY  - 1988
UR  - https://m2.mtmt.hu/api/publication/20134408
ID  - 20134408
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Durszt, E
TI  - On defect functions of contractions
JF  - OPERATOR THEORY: ADVANCES AND APPLICATIONS
J2  - OPER THER ADV APPL
VL  - 28
PY  - 1988
SP  - 61
EP  - 69
PG  - 9
SN  - 0255-0156
UR  - https://m2.mtmt.hu/api/publication/20134456
ID  - 20134456
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Kérchy, László
TI  - On the residual parts of completely non-unitary contractions
JF  - ACTA MATHEMATICA HUNGARICA
J2  - ACTA MATH HUNG
VL  - 50
PY  - 1987
SP  - 127
EP  - 145
PG  - 19
SN  - 0236-5294
DO  - 10.1007/BF01903372
UR  - https://m2.mtmt.hu/api/publication/1048377
ID  - 1048377
LA  - English
DB  - MTMT
ER  -