139 citations · 186 across the 16 of their papers we have counts for
5 papers · 2 filters
Spectral pictures of 2-variable weighted shifts
Raul E. Curto, Jasang Yoon
We study the spectral pictures of (jointly) hyponormal 2-variable weighted shifts with commuting subnormal components. By contrast with all known results in the theory of subnormal…
Propagation phenomena for hyponormal 2-variable weighted shifts
Raul E. Curto, Jasang Yoon
We study the class of hyponormal 2-variable weighted shifts with two consecutive equal weights in the weight sequence of one of the coordinate operators. We show that under natural…
Hyponormality and subnormality for powers of commuting pairs of subnormal operators
Raul E. Curto, Sang Hoon Lee, Jasang Yoon
Let H_0 (resp. H_\infty denote the class of commuting pairs of subnormal operators on Hilbert space (resp. subnormal pairs), and for an integer k>=1 let H_k denote the class of k-h…
Quartically hyponormal weighted shifts need not be 3-hyponormal
Raul E. Curto, Sang Hoon Lee
We give the first example of a quartically hyponormal unilateral weighted shift which is not 3-hyponormal.
The extremal truncated moment problem
Raul E. Curto, Lawrence A. Fialkow, H. Michael Moeller
For a degree 2n real d-dimensional multisequence β^(2n) to have a representing measure, it is necessary for the associated moment matrix M(n) to be positive semidefinite and for th…