We give a necessary and sufficient condition for the second quantification operator Γ(h) of a bounded operator h on L2 (R+), or for its differential second quantification operator λ(h), to have a representation as a quantum stochastic integral. This condition is exactly that h writes as the sum of a Hilbert-Schmidt operator and a multiplication operator. We then explore several extensions of th...

In this paper we obtained tensor product sum of Toeplitz and multiplication operator induced dynamical system on analytic Lipschitz spaces.

A necessary and sufficient condition for an operator space to support a multiplication making it completely isometric and isomorphic to a unital operator algebra is proved. The condition involves only the holomorphic structure of the Banach spaces underlying the operator space.

We estimate the essential norm of a weighted composition operator relatively to the class of Dunford-Pettis operators or the class of weakly compact operators, on the space H∞ of Dirichlet series. As particular cases, we obtain the precise value of the generalized essential norm of a composition operator and of a multiplication operator.

Nomenclature = normalized Euler rotation axis i<1-3> = indices of first, second and third Euler rotation, e.g. if rotation sequence is 3-2-1, i1 is 3, i2 is 2, and i3 is 1 i<1-3>n = next circular index following i<1-3>, e.g. if i2 = 3, i2n = 1 i<1-3>nn = next circular index following i<1-3>n, e.g. if i2n = 3, i2nn = 2 = Quaternion = = operator: rotation of vector by a quaternion vi = unit vecto...

In this paper we give a simple characterization of weighted Sobolev spaces (with piecewise monotonous weights) such that the multiplication operator is bounded: it is bounded if and only if the support of μ0 is large enough. We also prove some basic properties of the appropriate weighted Sobolev spaces. To have bounded multiplication operator has important consequences in Approximation Theory: ...

‎let $pa$ be a commutative banach algebra and $ex$ be a left banach $pa$-module‎. ‎we study the set‎ ‎$dec_{pa}(ex)$ of all elements in $pa$ which induce a decomposable multiplication operator on $ex$‎. ‎in the case $ex=pa$‎, ‎$dec_{pa}(pa)$ is the well-known apostol algebra of $pa$‎. ‎we show that $dec_{pa}(ex)$ is intimately related with the largest spectrally separable subalgebra of $pa$ and...

Sobolev orthogonal polynomials with respect to measures supported on subsets of the complex plane are considered. The connection between the following properties is studied: the multiplication operator M p(z) = zp(z) defined on the space P of algebraic polynomials with complex coefficients is bounded with respect to the norm defined by the Sobolev inner product, the supports of the measures are...