On operators with unitary ϱ-dilations
نویسندگان
چکیده
منابع مشابه
Constraint Unitary Dilations and Numerical Ranges
It is shown that each contraction A on a Hilbert space H, with A + A I for some 2 R, has a unitary dilation U on H H satisfying U + U I. This is used to settle a conjecture of Halmos in the aarmative: The closure of the numerical range of each contraction A is the intersection of the closures of the numerical ranges of all unitary dilations of A. By means of the duality theory of completely pos...
متن کاملGeneralized Scalar Operators as Dilations
It is shown that polynomially bounded operators on Banach spaces have polynomially bounded dilations which have spectrum in the unit circle and are generalized scalar. The proof also yields a description of all compressions of generalized scalar operators with spectrum in the unit circle.
متن کاملUnitary Operators on the Document Space
When people search for documents, they eventually want content, not words. Hence, search engines should relate documents more by their underlying concepts than by the words they contain. One promising technique to do so is Latent Semantic Indexing (LSI). LSI dramatically reduces the dimension of the document space by mapping it into a space spanned by conceptual indices. Empirically, the number...
متن کاملGeneralized Unitary Operators
1. Let C be the complex field and T be the unit circle { \ £ C : | \ | = 1} . For a non-negative integer m or for m = oo, let OCT) be the space of all m-times continuously differentiable functions on T. (Here we consider T as a C°°-manifold in the natural way. Thus, any / £ C m ( r ) can be identified with an m-times continuously differentiable periodic function f (6) of a real variable 0 with ...
متن کاملScalable Noise Estimation with Random Unitary Operators
Joseph Emerson,1 Robert Alicki,2 and Karol Życzkowski1, 3, 4 Perimeter Institute for Theoretical Physics, Waterloo, Ontario, Canada Institute of Theoretical Physics and Astrophysics, University of Gdańsk, Wita Stwosza 57, PL 80-952 Gdańsk, Poland Institute of Physics, Jagiellonian University, ul. Reymonta 4, 31-059 Cracow, Poland Center for Thoretical Physics, Polish Academy of Sciences, Al Lot...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Annales Polonici Mathematici
سال: 1997
ISSN: 0066-2216,1730-6272
DOI: 10.4064/ap-66-1-11-14