Let $\gamma\equiv\gamma^{\left (2n\right)} $ denote a sequence of complex numbers
$\gamma _ {00},\gamma _ {01},\gamma _ {10},\dots,\gamma _ {0, 2n},\dots,\gamma _ {2n, 0} …

Recursively generated weighted shifts are employed to exhibit a large collection of
quadratically hyponormal shifts which are not subnormal. This result is reached after …

This work explores joint hyponormality of Toeplitz pairs. Topics include: hyponormality of
Toeplitz pairs with one co-ordinate a Toeplitz operator with analytic polynomial symbol; …

For a degree 2 n real d-dimensional multisequence β ≡ β^(2n)={\beta_i\} _ i ∈ Z^ d _+,| i| ≦
2n to have a representing measure μ, it is necessary for the associated moment matrix M …

We study a general class of weighted shifts whose weights $\alpha $ are given by
$\alpha_n=\sqrt {\frac {p^ n+ N}{p^ n+ D}} $, where $ p> 1$ and $ N $ and $ D $ are …

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Given a doubly indexed finite sequence of complex numbers γ≡ γ (2n): γ00, γ01, γ10,…, γ0,
2n,…, γ2n, 0, with γ00> 0 and the truncated complex moment problem entails finding a …

In this paper, we are concerned with hyponormality and subnormality of block Toeplitz
operators acting on the vector-valued Hardy space [Formula: see text] of the unit circle. First …

In 1950, PR Halmos, motivated in part by the successful development of the theory of normal
operators, introduced the notions of subnormality and hyponormality for (bounded) Hilbert …

We construct three different families of commuting pairs of subnormal operators, jointly
hyponormal but not admitting commuting normal extensions. Each such family can be used …