Zobrazeno 1 - 10
of 61
pro vyhledávání: '"Marek Ptak"'
Publikováno v:
Opuscula Mathematica, Vol 44, Iss 3, Pp 341-357 (2024)
We generalize certain well known orthogonal decompositions of model spaces and obtain similar decompositions for the wider class of shifted model spaces, allowing us to establish conditions for near invariance of the latter with respect to certain op
Externí odkaz:
https://doaj.org/article/6457272e35734c1cb670297e4963aa89
Autor:
Elżbieta Król-Klimkowska, Marek Ptak
Publikováno v:
Annales Universitatis Paedagogicae Cracoviensis: Studia Mathematica, Vol 15, Pp 97-106 (2016)
The investigation of properties of generalized Toeplitz operators with respect to the pairs of doubly commuting contractions (the abstract analogue of classical two variable Toeplitz operators) is proceeded. We especially concentrate on the conditio
Externí odkaz:
https://doaj.org/article/373c56a4e3d540aaa5385083d4fdf03c
Autor:
Kamila Piwowarczyk, Marek Ptak
Publikováno v:
Opuscula Mathematica, Vol 36, Iss 6, Pp 799-806 (2016)
Power partial isometries are not always hyperreflexive neither reflexive. In the present paper it will be shown that power partial isometries are always hyporeflexive and \(2\)-hyperreflexive.
Externí odkaz:
https://doaj.org/article/4fc5488a9dc4432cb7f4db9f669e1018
Autor:
Wojciech Młocek, Marek Ptak
Publikováno v:
Opuscula Mathematica, Vol 34, Iss 3, Pp 561-567 (2014)
The results of hyperreflexivity or 2-hyperreflexivity for subspaces of Toeplitz operators on the Hardy spaces on Jordan regions or upper half-plane are given.
Externí odkaz:
https://doaj.org/article/c44a38f01f5546758767993bb1e84958
Publikováno v:
Canadian Journal of Mathematics. :1-27
Motivated by the near invariance of model spaces for the backward shift, we introduce a general notion of $(X,Y)$ -invariant operators. The relations between this class of operators and the near invariance properties of their kernels are studied. Tho
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::be7c1cb31196932499c87c0fb9c446ee
https://doi.org/10.4153/s0008414x23000196
https://doi.org/10.4153/s0008414x23000196
Publikováno v:
Studia Mathematica. 269:83-106
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::851a1332b779337f7d8bcc6805d25264
https://doi.org/10.4064/sm210928-19-9
https://doi.org/10.4064/sm210928-19-9
Publikováno v:
Integral Equations and Operator Theory. 94
We study conjugations in $$L^2(\mathbb {T})$$ L 2 ( T ) and their relation with kernels of Toeplitz operators on $$H^2(\mathbb {T})$$ H 2 ( T ) space. Such kernels are a generalization of model spaces. We investigate properties of an inequality relat
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::74176988024f4126dfdbd1ecd61d0063
https://doi.org/10.1007/s00020-022-02714-3
https://doi.org/10.1007/s00020-022-02714-3
Publikováno v:
Complex Analysis and Operator Theory. 16
We study conjugations on $$L^2(\mathbb {T}^N)$$ L 2 ( T N ) and their behaviour with respect to multiplication operators. Full characterizations of conjugations commuting or intertwining with multiplication operators are obtained. We also characteriz
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::35bec69d0e19c25502ec9eef4bbb5748
https://doi.org/10.1007/s11785-022-01251-6
https://doi.org/10.1007/s11785-022-01251-6
Publikováno v:
Forum Mathematicum. 33:987-996
We refine a result of [J. E. McCarthy, Common range of co-analytic Toeplitz operators, J. Amer. Math. Soc. 3 1990, 4, 793–799] and explore the common range of the co-analytic Toeplitz operators on a model space. The tools used to do this also yield
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::422d61cd1eb0eadf9f2b5f0682e4f064
https://doi.org/10.1515/forum-2021-0092
https://doi.org/10.1515/forum-2021-0092
The properties of being shift invariant and being reflexive or transitive in the case of the space of (asymmetric) truncated Toeplitz operators, and the space of (asymmetric) dual truncated operators are investigated. Most of the results obtained are
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::57d30c03f432d63a5069cc324ab124fa
http://arxiv.org/abs/2203.09265
http://arxiv.org/abs/2203.09265
