International Journal of Mathematics and Mathematical Sciences
Volume 2005 (2005), Issue 12, Pages 1925-1932
doi:10.1155/IJMMS.2005.1925
Fractional powers of hyponormal operators of Putnam type
Department of Mathematics, Howard University, 2441 Sixth Street NW, Washington, DC 20059, USA
Received 20 January 2005; Revised 12 April 2005
Copyright © 2005 Toka Diagana. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
We are concerned with fractional powers of the so-called
hyponormal operators of Putnam type. Under some suitable
assumptions it is shown that if A, B are closed hyponormal
linear operators of Putnam type acting on a complex Hilbert space
ℍ, then D((A+B¯)α)=D(Aα)∩D(Bα)=D((A+B¯)∗α) for each α∈(0,1). As an application, a large class of the Schrödinger's operator with a
complex potential Q∈Lloc1(ℝd)+L∞(ℝd) is considered.