On unitary equivalence of invariant subspaces of the Dirichlet space
Kunyu Guo, Liankuo Zhao (2010)
Studia Mathematica
Similarity:
It is shown that in the Dirichlet space , two invariant subspaces ℳ ₁, ℳ ₂ of the Dirichlet shift are unitarily equivalent only if ℳ ₁ = ℳ ₂.