Generalized composition operators from F(p, q, s) spaces to Bloch-type spaces

Let H(B) denote the space of all holomorphic functions on the unit ball B of Cⁿ. Let φ be a holomorphic self-map of B and g ∈ H(B) such that g(0) = 0. In this paper, we investigate the boundedness and compactness of the generalized composition operator

     

On an integral-type operator from logarithmic Bloch-type spaces to mixed-norm spaces on the unit ball

Let H(B) denote the space of all holomorphic functions on the open unit ball B of Cⁿ and g∈H(B). We characterize the boundedness and compactness of the following integral-type operator

     

Integral-type operators acting between weighted-type spaces on the unit ball

Let B denote the unit ball in Cⁿ and H(B) the space of all holomorphic functions on B. We study the boundedness and compactness of the following integral-type operators

     

On an integral-type operator between bloch-type spaces

Let H(B) denote the space of all holomorphic functions on the unit ball B of . Let φ be a holomorphic self-map of B and gH(B), such that g(0)=0. We study the boundedness and compactness of the following integral-type operator recently introduced by Stević

between Bloch-type spaces. Our main results are natural extensions of some results in the following paper: S. Stević, On a new integral-type operator from the Bloch space to Bloch-type spaces on the unit ball, J. Math. Anal. Appl. 354 (2009) 426–434.     

Weighted composition operators from area Nevanlinna spaces into Bloch spaces

Let H(D) denote the class of all analytic functions on the open unit disk D of C. Let φ be an analytic self-map of D and u∈H(D). The weighted composition operator is defined by

     

On a new integral-type operator from the Bloch space to Bloch-type spaces on the unit ball

We introduce the following integral-type operator on the space H(B) of all holomorphic functions on the unit ball B⊂Cn

     

Integral-type operators between α-Bloch spaces and Besov spaces on the unit ball

Let H(B) denote the space of all holomorphic functions on the unit ball B⊂Cⁿ. The boundedness and compactness of the following integral-type operators

     

Converse theorem for the Minkowski inequality

Let (Ω,Σ,μ) a measure space such that 0<μ(A)<1<μ(B)<∞ for some A,B∈Σ. Under some natural conditions on the bijective functions φ,φ₁,φ₂,ψ,ψ₁,ψ₂:(0,∞)→(0,∞) we prove that if

     

On zero varieties of holomorphic functions in Hardy spaces

In contrast to the famous Henkin-Skoda theorem concerning the zero varieties of holomorphic functions in the Nevanlinna class on the open unit ball B_n in , n?2, it is proved in this article that for any nonnegative, increasing, convex function ?(t) defined on , there exists satisfying such that there is no f∈H^p(B_n), 0<p<∞, with . Here N_g(ζ,1) denotes the integrated zero counting function associated with the slice function g_ζ. This means that the zero sets of holomorphic functions belonging to the Hardy spaces H^p(B_n), 0<p<∞, unlike that of the holomorphic functions in the Nevanlinna class, cannot be characterized in the above manner.     

Young’s inequality and trace

Let φ be a positive linear functional on M_n(C) and f,g mutually conjugate in the sense of Young. In this note we show a necessary and sufficient condition for the inequality

     

On a class of analytic functions with missing coefficients

Let T_n(A,B,α) denote the class of functions of the form:

     

Weighted differentiation composition operators from mixed-norm spaces to weighted-type spaces

Motivated by the recent paper [X. Zhu, Products of differentiation composition and multiplication from Bergman type spaces to Bers spaces, Integral Transform. Spec. Funct. 18 (3) (2007) 223-231], we study the boundedness and compactness of the weighted differentiation composition operator , where u is a holomorphic function on the unit disk D, φ is a holomorphic self-map of D and n∈N₀, from the mixed-norm space H(p, q, ?), where p,q > 0 and ? is normal, to the weighted-type space or the little weighted-type space . For the case of the weighted Bergman space , p > 1, some bounds for the essential norm of the operator are also given.     

On the injective norm and characterization of some subclasses of normal operators by inequalities or equalities

Let B(H) be the C^*-algebra of all bounded linear operators acting on a complex Hilbert space H. In this note, we shall show that if S is an invertible normal operator in B(H) the following estimation holds

     

Le problème de Yamabe avec singularités

Let (Mn,g) be a compact riemannian manifold of dimension n?3. Under some assumptions, we prove that there exists a positive function φ solution of the Yamabe equation

     

Uniformly continuous superposition operators in the Banach space of Hölder functions

Let I,J⊂R be intervals. One of the main results says that if a superposition operator H generated by a two place ,

H(φ)(x):=h(x,φ(x)),     

Certain series attached to an even number of elliptic modular forms

For j=1,…,n let f_j(z) and g_j(z) be holomorphic modular forms for such that f_j(z)g_j(z) is a cusp form. We define a series

     

Integral-type operators from Bloch-type spaces to Zygmund-type spaces

Let denote the space of all holomorphic functions on the unit ball . This paper investigates the following integral-type operator with symbol

where is the radial derivative of g. The boundedness and compactness of the operator T_g from Bloch-type spaces to Zygmund-type spaces are studied.     

Strong convergence theorems for nonexpansive semigroup in Banach spaces

Let K be a nonempty closed convex subset of a reflexive and strictly convex Banach space E with a uniformly Gâteaux differentiable norm, and a nonexpansive self-mappings semigroup of K, and a fixed contractive mapping. The strongly convergent theorems of the following implicit and explicit viscosity iterative schemes {xn} are proved.

xn=αnf(xn)+(1−αn)T(tn)xn,