Spectral measures and automatic continuity.
Spectral properties of G-symbolic Morse shifts
Spectral theory from the second-order -difference operator.
Spectral trajectories,duality and inductive-projective limits of Hilbert spaces
Spectral transition parameters for a class of Jacobi matrices
This paper initially considers a class of unbounded Jacobi matrices defined by an increasing sequence of repeated weights. Spectral parameters are then introduced in various ways to allow the authors to study the nature and location of the spectrum as a function of these parameters.
Stable invariant subspaces for operators on Hilbert space
If T is a bounded operator on a separable complex Hilbert space ℋ, an invariant subspace ℳ for T is stable provided that whenever is a sequence of operators such that , there is a sequence of subspaces , with in for all n, such that in the strong operator topology. If the projections converge in norm, ℳ is called a norm stable invariant subspace. This paper characterizes the stable invariant subspaces of the unilateral shift of finite multiplicity and normal operators. It also shows that...
Structure of the antieigenvectors of a strictly accretive operator.
Subnormal operators, cyclic vectors and reductivity
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.
Subnormality and cyclicity
For an unbounded operator S the question whether its subnormality can be built up from that of every , the restriction of S to a cyclic space generated by f in the domain of S, is analyzed. Though the question at large has been left open some partial results are presented and a possible way to prove it is suggested as well.