Results 21 to 30 of about 392,532 (306)

Hardy spaces of generalized analytic functions and composition operators

open access: yesConcrete Operators, 2018
We present some recent results on Hardy spaces of generalized analytic functions on D specifying their link with the analytic Hardy spaces. Their definition can be extended to more general domains Ω . We discuss the way to extend such definitions to more
Pozzi Elodie
doaj   +1 more source

On Unbounded Composition Operators in $L^2$-Spaces

open access: yes, 2012
Fundamental properties of unbounded composition operators in $L^2$-spaces are studied. Characterizations of normal and quasinormal composition operators are provided. Formally normal composition operators are shown to be normal.
A Brown   +52 more
core   +2 more sources

Composite operators in QCD [PDF]

open access: yesNuclear Physics B, 1992
We give a formula for the derivatives of a correlation function of composite operators with respect to the parameters (i.e., the strong fine structure constant and the quark mass) of QCD in four-dimensional euclidean space. The formula is given as spatial integration of the operator conjugate to a parameter. The operator product of a composite operator
openaire   +2 more sources

Iteration of Composition Operators on small Bergman spaces of Dirichlet series

open access: yesConcrete Operators, 2018
The Hilbert spaces ℋw consisiting of Dirichlet series F(s)=∑n=1∞ann-s$F(s) = \sum\nolimits_{n = 1}^\infty {{a_n}{n^{ - s}}}$ that satisfty ∑n=1∞|an|2/wn 0 and {wn}n having average order (logj+n)α${(\log _j^ + n)^\alpha }$, that the composition operators ...
Zhao Jing
doaj   +1 more source

Universal composition operators

open access: yesJournal of Operator Theory, 2021
A Hilbert space operator U is called \textit{universal} (in the sense of Rota) if every Hilbert space operator is similar to a multiple of U restricted to one of its invariant subspaces. It follows that the \textit{invariant subspace problem} for Hilbert spaces is equivalent to the statement that all minimal invariant subspaces for U are one ...
Carmo, João R., Noor, S. Waleed
openaire   +2 more sources

Growth Spaces on Circular Domains Taking Values in a Banach Lattice, Embeddings and Composition Operators

open access: yesMathematics
We introduce the space of holomorphic growth spaces with values in a Banach lattice. We provide norm and essential norm estimates of the embedding operator, and we completely characterize the bounded and compact embeddings of the growth spaces using ...
Nihat Gökhan Göğüş
doaj   +1 more source

M-quasi-hyponormal composition operators

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 1987
A necessary and sufficient condition is obtained for M-quasi-hyponormal composition operators. It has also been proved that the class of M-quasi-hyponormal composition operators coincides with the class of M-paranormal composition operators. Existence of
Pushpa R. Suri, N. Singh
doaj   +1 more source

Weighted composition operators between different Fock spaces

open access: yes, 2017
We study weighted composition operators acting between Fock spaces. The following results are obtained: (1) Criteria for the boundedness and compactness; (2) Characterizations of compact differences and essential norm; (3) Complete descriptions of path ...
Khoi, Le Hai, Tien, Pham Trong
core   +1 more source

The weighted composition operators on the large weighted Bergman spaces

open access: yes, 2018
In this paper, we characterize bounded, compact or Schatten class weighted composition operators acting on Bergman spaces with the exponential type weights. Moreover, we give the proof of the necessary part for the boundedness of composition operators on
Park, Inyoung
core   +1 more source

Revealing the structure of land plant photosystem II: the journey from negative‐stain EM to cryo‐EM

open access: yesFEBS Letters, EarlyView.
Advances in cryo‐EM have revealed the detailed structure of Photosystem II, a key protein complex driving photosynthesis. This review traces the journey from early low‐resolution images to high‐resolution models, highlighting how these discoveries deepen our understanding of light harvesting and energy conversion in plants.
Roman Kouřil
wiley   +1 more source

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