Results 51 to 60 of about 169 (75)

Rational functions associated with the white noise space and related topics [PDF]

arXiv, 2008
Motivated by the hyper-holomorphic case we introduce and study rational functions in the setting of Hida's white noise space. The Fueter polynomials are replaced by a basis computed in terms of the Hermite functions, and the Cauchy-Kovalevskaya product is replaced by the Wick product.
arxiv  

Curvature Condition for Noncontractions does not imply Similarity to the Backward Shift [PDF]

arXiv, 2009
We give an example of an operator that satisfies the curvature condition as defined in [2], but is not similar to the backward shift S* on the Hardy class H^2. We conclude therefore that the contraction assumption in the similarity characterization given in [2] is a necessary requirement.
arxiv  

Three-Colorings of Cubic Graphs and Tensor Operators [PDF]

arXiv, 2010
Penrose's work \cite{8} established a connection between the edge 3-colorings of cubic planar graphs and tensor algebras. We exploit this point of view in order to get algebraic representations of the category of cubic graphs with free ends.
arxiv  

Similarity of Cowen-Douglas operators to the backward Dirichlet shift [PDF]

arXiv, 2013
We show that the same similarity characterization obtained for Cowen-Douglas operators to the backward shift operators on reproducing kernel Hilbert spaces with analytic kernels can be used to describe similarity in the Dirichlet space setting. As in previous proofs, a model theorem that allows one to get the eigenvector bundle structure of the ...
arxiv  

Operator upper bounds for Davis-Choi-Jensen's difference in Hilbert spaces [PDF]

In this paper we obtain several operator inequalities providing upper bounds for the Davis-Choi-Jensen's Difference Ph (f (A)) - f (Ph (A)) for any convex function f : I → R, any selfadjoint operator A in H with the spectrum Sp (A) ⊂ I and any linear ...
Dragomir Silvestru Sever
core   +1 more source

Bounding the Čebyšev function for a differentiable function whose derivative is h or λ-convex in absolute value and applications [PDF]

, 2016
Some bounds for the Čebyšev functional of a differentiable function whose derivative is h or λ-convex in absolute value and applications for functions of selfadjoint operators in Hilbert spaces via the spectral representation theorem are ...
Dragomir, Sever S
core   +1 more source

Spectral Radius Inequalities for Functions of Operators Defined by Power Series [PDF]

arXiv, 2013
By the help of power series f we can naturally construct another power series that has as coefficients the absolute values of the coefficients of f. Utilising these functions we prove some inequalities for the spectral radius of the bounded linear operator f(T) on a complex Hilbert space and some functions of its norm.
arxiv  

Classification of Graph Fractaloids [PDF]

arXiv, 2009
In this paper, we observe graph fractaloids, which are the graph groupoids with fractal property. In particular, we classify them in terms of the spectral data of certain Hilbert space operators, called the radial operators. Based on these information, we can define the pair of two numbers $(N_{0},$ $N^{0})$, for a given graph fractaloid G, called the ...
arxiv  

C*-algebras Associated do Stationary Ordered Bratteli Diagrams [PDF]

arXiv, 2011
In this paper, we introduce a C*-algebra associated to any substitution (via its Bratteli diagram model). We show that this C*-algebra contains the partial crossed product C*-algebra of the corresponding Bratteli-Vershik system and show that these algebras are invariant under equivalence of the Bratteli diagrams. We also show that the isomorphism class
arxiv  

A Bohl-Bohr-Kadets type theorem characterizing Banach spaces not containing c0 [PDF]

arXiv, 2013
We prove that a separable Banach space $E$ does not contain a copy of the space $\co$ of null-sequences if and only if for every doubly power-bounded operator $T$ on $E$ and for every vector $x\in E$ the relative compactness of the sets $\{T^{n+m}x-T^nx: n\in \NN\}$ (for some/all $m\in\NN$, $m\geq 1$) and $\{T^nx:n\in \NN\}$ are equivalent.
arxiv