Displaying similar documents to “Numerical radius inequalities for Hilbert space operators. II”

Numerical radius inequalities for Hilbert space operators

Fuad Kittaneh (2005)

Studia Mathematica

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It is shown that if A is a bounded linear operator on a complex Hilbert space, then 1/4 ||A*A + AA*|| ≤ (w(A))² ≤ 1/2 ||A*A + AA*||, where w(·) and ||·|| are the numerical radius and the usual operator norm, respectively. These inequalities lead to a considerable improvement of the well known inequalities 1/2 ||A|| ≤ w(A) ≤ || A||. Numerical radius inequalities for products and commutators of operators are also obtained. ...

Numerical radius inequalities for 2 × 2 operator matrices

Omar Hirzallah, Fuad Kittaneh, Khalid Shebrawi (2012)

Studia Mathematica

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We derive several numerical radius inequalities for 2 × 2 operator matrices. Numerical radius inequalities for sums and products of operators are given. Applications of our inequalities are also provided.

A convex treatment of numerical radius inequalities

Zahra Heydarbeygi, Mohammad Sababheh, Hamid Moradi (2022)

Czechoslovak Mathematical Journal

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We prove an inner product inequality for Hilbert space operators. This inequality will be utilized to present a general numerical radius inequality using convex functions. Applications of the new results include obtaining new forms that generalize and extend some well known results in the literature, with an application to the newly defined generalized numerical radius. We emphasize that the approach followed in this article is different from the approaches used in the literature to...

Inequalities of DVT-type -- the one-dimensional case

Barbora Batíková, Tomáš J. Kepka, Petr C. Němec (2020)

Commentationes Mathematicae Universitatis Carolinae

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In this note, particular inequalities of DVT-type in real and integer numbers are investigated.