Results 261 to 270 of about 4,538,824 (321)
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Acta Scientiarum Mathematicarum
Satyajit Sahoo, H. Moradi, M. Sababheh
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Satyajit Sahoo, H. Moradi, M. Sababheh
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Sharper bounds for the numerical radius
Linear and multilinear algebra, 2023In this paper, we discuss and present new sharp inequalities for the numerical radii of Hilbert space operators. In particular, if A and B are bounded linear operators on a Hilbert space, we present new upper bounds for $ \omega (A^*B) $ ω(A∗B). The main
F. Kıttaneh, H. Moradi, M. Sababheh
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q-Numerical radius inequalities for Hilbert space
Linear and multilinear algebra, 2023The aim of this paper is to study the q-numerical radius $ \omega _{q}(.) $ ωq(.) of bounded linear operators on Hilbert spaces. More precisely, first, we show that $ \omega _{q}(.) $ ωq(.) defines a norm which is equivalent to the operator norm.
Sadaf Fakhri Moghaddam +2 more
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Weighted numerical radius inequalities for operator and operator matrices
Acta Scientarum Mathematicarum, 2023The concept of weighted numerical radius has been defined recently. In this article, we obtain several upper bounds for the weighted numerical radius of operators and $$2 \times 2$$ 2 × 2 operator matrices which generalize and improve some well-known ...
R. Nayak
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Numerical-Radius-Attaining Polynomials
The Quarterly Journal of Mathematics, 2003zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Acosta, M. D. +2 more
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Advancement of Numerical Radius Inequalities of Operators and Product of Operators
Iranian Journal of Science, 2023In this article, we prove upper bounds for the numerical radius of bounded linear operator and product of operators, which generalize and improve existing inequalities.
R. Nayak
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Linear and Multilinear Algebra, 2002
Let V be a direct sum of full matrix algebras, or the algebra of block upper triangular matrices. Suppose r ( A ) is the numerical radius of $A \in V$ . We characterize mappings $f: V \rightarrow V$ that satisfy $r(\;f(A)-f(B)) = r(A-B) \ {\rm for \ all} \ A, B \in V$ .
Chi-Kwong Li, Peter Šemrl
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Let V be a direct sum of full matrix algebras, or the algebra of block upper triangular matrices. Suppose r ( A ) is the numerical radius of $A \in V$ . We characterize mappings $f: V \rightarrow V$ that satisfy $r(\;f(A)-f(B)) = r(A-B) \ {\rm for \ all} \ A, B \in V$ .
Chi-Kwong Li, Peter Šemrl
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Mean Inequalities for the Numerical Radius
Numerical Functional Analysis and Optimization, 2023Extending certain scalar and norm inequalities, we present new inequalities for the numerical radius, which generalize and refine some known results.
F. Kıttaneh, H. Moradi, M. Sababheh
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Roberts numerical radius orthogonality
Linear and Multilinear Algebra, 2021We deal with the Roberts numerical radius orthogonality. In the case of 2 × 2 complex matrices, we give some necessary and sufficient conditions for the numerical range to be symmetric by employing...
Elias Faryad +2 more
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