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Hansong Huang

Publications and source records attributed to Hansong Huang.

6 recordsLinked to original sources

Multiplication operators on the Bergman space of bounded domains in C^d

In this paper we study multiplication operators on Bergman spaces of high dimensional bounded domains and those von Neumann algebras induced by them via the geometry of domains and function theory of their symbols. In particular, using local inverses and $L^2_a$-removability, we show that for a holomorphic proper map $Φ=(ϕ_1, ϕ_2, \cdots , ϕ_d)$ on a bounded domain $Ω$ in $\mathbb{C}^{d}$, the dimension of the von Neumann algebra $\mathcal{V}^*(Φ,Ω) $ consisting of bounded operators on the Bergman space $L_a^2(Ω)$, which commute with both $ M_{ϕ_j}$ and its adjoint $M_{ϕ_j}^*$ for each $j$, equals the number of components of the complex manifold $\mathcal{S}_{Φ}= \{(z,w)\in Ω^2: Φ(z)=Φ(w),\, z\not\in Φ^{-1}(Φ(Z))\},$ where $Z$ is the zero variety of the Jacobian $JΦ$ of $ Φ.$ This extends the main result in \cite{DSZ} in high dimensional complex domains. Moreover we show that the von Neumann algebra $\mathcal{V}^*(Φ,Ω) $ may not be abelian in general although Douglas, Putinar and Wang \cite{DPW} showed that $\mathcal{V}^*(Φ,\mathbb{D})$ for the unit disk $\mathbb{D}$ is abelian.

math.OA

A tuple of multiplication operators defined by twisted holomorphic proper maps

This paper mainly concerns the von Neumann algebras induced by a tuple of multiplication operators on Bergman spaces which arise essentially from holomorphic proper maps over higher dimensional domains. We study the structures and abelian properties of the related von Neumann algebras, and in interesting cases they turns out to be tightly related to a Riemann manifold. There is a close interplay between operator theory, geometry and complex analysis. Many examples are presented.

math.OA

Totally Abelian Toeplitz operators and geometric invariants associated with their symbol curves

This paper mainly studies totally Abelian operators in the context of analytic Toeplitz operators on both the Hardy and Bergman space. When the symbol is a meromorphic function on $\mathbb{C}$, we establish the connection between totally Abelian property of these operators and and geometric properties of their symbol curves. It is found that winding numbers and multiplicities of self-intersection of symbol curves play an important role in this topic. Techniques of group theory, complex analysis, geometry and operator theory are intrinsic in this paper. As a byproduct, under a mild condition we provides an affirmative answer to a question raised in \cite{BDU,T1}, and also construct some examples to show that the answer is negative if the associated conditions are weakened.

math.CV

Multiplication operators defined by a class of polynomials on L_a^2(D^2)

In this paper, we consider those multiplication operators M_p on the Bergman space L_a^2(D^2) over the bidisk, defined by a class of polynomials p. Also, this paper consider the reducing subspaces of M_p, the von Neumann algebra W^*(p) generated by M_p, and its commutant V^*(p)=W^*(p)'. The structure of V^*(p) is completely determined, along with those reducing subspaces of M_p.

math.OA

Cowen's class and Thomson's class

In studying commutants of analytic Toeplitz operators, Thomson proved a remarkable theorem which states that under a mild condition, the commutant of an analytic Toeplitz operator is equal to that of Toeplitz operator defined by a finite Blaschke product. Cowen gave an significant improvement of Thosom's result. In this paper, we will present examples in Cowen's class which does not lie in Thomson's class.

math.CV

Geometric constructions of thin Blaschke products and reducing subspace problem

In this paper, we mainly study geometric constructions of thin Blaschke products $B$ and reducing subspace problem of multiplication operators induced by such symbols $B$ on the Bergman space. Considering such multiplication operators $M_B$, we present a representation of those operators commuting with both $M_B$ and $M_B^*$. It is shown that for "most" thin Blaschke products $B$, $M_B$ is irreducible, i.e. $M_B$ has no nontrivial reducing subspace; and such a thin Blaschke product $B$ is constructed. As an application of the methods, it is proved that for "most" finite Blaschke products $ϕ$, $M_ϕ$ has exactly two minimal reducing subspaces. Furthermore, under a mild condition, we get a geometric characterization for when $M_B$ defined by a thin Blaschke product $B$ has a nontrivial reducing subspace.

math.FA