本文研究了Dirichlet空间D上由二阶Blaschke积φ定义的乘法算子Mφ的酉等价类.主要结果表明对于D的一个乘子ψ,乘法算子Mψ酉等价于Mφ当且仅当存在常数θ,|θ|=1,使得ψ(z):ψ(θz).这一结果是完全不同于Hardy空间与Bergman空间上的相应结果.
The unitary equivalence of multiplication operator Ms on the Dirichlet space D is studied, where φ is a Blaschke product of order two. The main result shows that for a multiplier ψ of D, the multiplication operator Mψ is unitarily equivalent to Me if and only if ψ(z) = φ(θz) for some constant 8 with |θ| = 1. This is very different from the corresponding result in the Hardy space and in the Bergman space.