# Search results for: George R. Exner

Computational Methods and Function Theory > 2019 > 19 > 2 > 193-225

*z*of $$\mathbb {D}$$ D , the subspace generated by the reproducing kernels $$k_{\varphi...

Integral Equations and Operator Theory > 2018 > 90 > 6 > 1-36

*subnormal completion problem*is to determine whether the weights may be completed to the weights of an injective, bounded, subnormal weighted shift on the Hilbert space arising from the full tree. We study this problem (which generalizes significantly the classical subnormal completion problem for weighted shifts) both from a measure-theoretic...

Complex Analysis and Operator Theory > 2019 > 13 > 1 > 241-255

*moment infinitely divisible*(MID) if, for every $$t > 0$$ t > 0 , the shift with weight sequence $$\alpha ^t: \alpha _0^t, \alpha _1^t, \ldots $$ α t : α 0 t , α 1 t , … is subnormal. Assume that $$W_{\alpha }$$...

Journal of Mathematical Analysis and Applications > 2017 > 451 > 1 > 544-564

Journal of Mathematical Analysis and Applications > 2017 > 450 > 1 > 444-460

Integral Equations and Operator Theory > 2017 > 88 > 2 > 229-248

*m*-step extension of a recursive weight sequence and let $$ W_{\alpha }$$ W α be the weighted shift associated with $$\alpha $$ α . In this paper we characterize the semi-cubic hyponormality of $$W_{\alpha }$$...

Integral Equations and Operator Theory > 2016 > 84 > 3 > 429-450

*p*-th power of each weight or forming the Aluthge transform. We determine in a number of cases whether the resulting shift is subnormal, and, if it is, find a concrete representation of the associated Berger measure, directly for finitely atomic measures, and using both Laplace transform and Fourier transform...

Journal of Mathematical Analysis and Applications > 2015 > 427 > 2 > 581-599

Integral Equations and Operator Theory > 2014 > 79 > 1 > 49-66

Journal of Mathematical Analysis and Applications > 2013 > 408 > 1 > 298-305

Journal of Mathematical Analysis and Applications > 2011 > 376 > 2 > 576-587

Integral Equations and Operator Theory > 2008 > 60 > 4 > 451-467

*n*-contractive and

*n*-hypercontractive Hilbert space operators (

*n*= 1, 2, . . .), classes weaker than, but related to, the class of subnormal operators. The

*k*-hyponormal operators are the more thoroughly explored examples of classes weaker than subnormal; we show that

*k*-hyponormality implies 2

*k*-contractivity. Turning to weighted shifts, it is shown that if a weighted shift is...

Integral Equations and Operator Theory > 2006 > 56 > 4 > 451-468

*n*-hypercontractive Hilbert space operators, primarily weighted shifts, and obtain results for back step extensions of recursively generated subnormal weighted shifts and for perturbations in the first weight of the Bergman shift. We compare the results with those for the classes of

*k*-hyponormal operators, and recapture, by an

*n*-hypercontractive approach,...