AbstractIn this note, we give a characterization of a pair (A,B) of positive contractions with commutator AB−BA of maximum possible norm. A necessary and sufficient condition is that either 1+i4‖A‖‖B‖ or its complex conjugate is in the closure of the numerical range of AB
AbstractGiven a sequence of bounded operators aj on a Hilbert space H with ∑j=1∞aj⁎aj=1=∑j=1∞ajaj⁎, ...
AbstractWe give an explicit description of all ρ-contractive (in Nagy–Foiaş sense) 2×2 matrices. Thi...
AbstractWe devote this note to the study of strict ρ-contractions. We characterize such operators in...
AbstractIn this note, we give a characterization of a pair (A,B) of positive contractions with commu...
AbstractLet A and B be bounded linear operators acting on a Hilbert space H. It is shown that the tr...
AbstractWe use certain norm inequalities for 2×2 operator matrices to establish norm inequalities fo...
AbstractIt is shown that if A and B are positive operators on a separable complex Hilbert space, and...
AbstractSome inequalities for the numerical radius, the operator norm and the maximum of the real pa...
AbstractIn this note, some norm inequalities for the commutator XY-YX and for the expression XY-YXT ...
AbstractIt is known that for any nonzero complex n×n matrices X and Y the quotient of Frobenius norm...
AbstractWe prove singular value inequalities for positive operators. Some of these inequalities gene...
AbstractWe show that if A is a C0 contraction with minimal function ϕ such that w(A)=w(S(ϕ)), where ...
AbstractLet A be a contraction on Hilbert space H and φ a finite Blaschke product. In this paper, we...
The main aim of the present paper is to establish various sharp upper bounds for the Euclidean oper...
AbstractThis note is focused upon positive linear operators which preserve the quadratic test functi...
AbstractGiven a sequence of bounded operators aj on a Hilbert space H with ∑j=1∞aj⁎aj=1=∑j=1∞ajaj⁎, ...
AbstractWe give an explicit description of all ρ-contractive (in Nagy–Foiaş sense) 2×2 matrices. Thi...
AbstractWe devote this note to the study of strict ρ-contractions. We characterize such operators in...
AbstractIn this note, we give a characterization of a pair (A,B) of positive contractions with commu...
AbstractLet A and B be bounded linear operators acting on a Hilbert space H. It is shown that the tr...
AbstractWe use certain norm inequalities for 2×2 operator matrices to establish norm inequalities fo...
AbstractIt is shown that if A and B are positive operators on a separable complex Hilbert space, and...
AbstractSome inequalities for the numerical radius, the operator norm and the maximum of the real pa...
AbstractIn this note, some norm inequalities for the commutator XY-YX and for the expression XY-YXT ...
AbstractIt is known that for any nonzero complex n×n matrices X and Y the quotient of Frobenius norm...
AbstractWe prove singular value inequalities for positive operators. Some of these inequalities gene...
AbstractWe show that if A is a C0 contraction with minimal function ϕ such that w(A)=w(S(ϕ)), where ...
AbstractLet A be a contraction on Hilbert space H and φ a finite Blaschke product. In this paper, we...
The main aim of the present paper is to establish various sharp upper bounds for the Euclidean oper...
AbstractThis note is focused upon positive linear operators which preserve the quadratic test functi...
AbstractGiven a sequence of bounded operators aj on a Hilbert space H with ∑j=1∞aj⁎aj=1=∑j=1∞ajaj⁎, ...
AbstractWe give an explicit description of all ρ-contractive (in Nagy–Foiaş sense) 2×2 matrices. Thi...
AbstractWe devote this note to the study of strict ρ-contractions. We characterize such operators in...
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