Date & Time: Wednesday, November 9, 2011, 15:00-16:00
Venue: Ramanujan Hall

Title: n-contractivity and k-hyponormality: some measure considerations

Speaker: Prof. George Exner, Bucknell University, USA

Abstract: We return to questions of the relationship between k-hyponormality and n-contractivity for weighted shifts arising as a perturbation of a subnormal shift, and generalize somewhat the results presented in the first talk. The results highlight the crucial role of the underlying Berger measure for the subnormal shift, and we close with some further directions for research (such as the apparently difficult problem of determining the Berger measure of some transformation of a subnormal shift even when the resulting shift is known to be subnormal).