Displaying similar documents to “Comparison results for two-dimensional half-linear cyclic differential systems”

Subnormal operators, cyclic vectors and reductivity

Béla Nagy (2013)

Studia Mathematica

Similarity:

Two characterizations of the reductivity of a cyclic normal operator in Hilbert space are proved: the equality of the sets of cyclic and *-cyclic vectors, and the equality L²(μ) = P²(μ) for every measure μ equivalent to the scalar-valued spectral measure of the operator. A cyclic subnormal operator is reductive if and only if the first condition is satisfied. Several consequences are also presented.