AbstractFor a given self-adjoint matrix H with ∥H∥ = 1 and tr(H) = 0, we consider the number γ(H) which is defined to be the minimum of ∥T∥2 for those T satisfying [T∗,T] = H. We show that 1 ⩽ γ(H) ⩽ 2 and that γ(H) is close to 2 if H is suitably chosen
Abstract. In this paper an easier proof is obtained of Alexandru Aleman’s extension of an inequality...
AbstractIt is shown that the infimum over all choices of the operator X of the norm of the operator ...
AbstractLet H and K be Hilbert spaces, and suppose A ε B(H) and B ε B(K) are self-adjoint operators ...
AbstractFor a given self-adjoint matrix H with ∥H∥ = 1 and tr(H) = 0, we consider the number γ(H) wh...
AbstractIt is shown that if A and B are n × n complex matrices with A = A∗ and ∥AB − BA∥</ 2ϵ2(n − 1...
Since the late 1960's mathematicians working mainly in the area of quantum field theory have used c...
AbstractFor bounded Hilbert space operators and for all unitarily invariant norms there hold||||A−B|...
It is shown that if A and B are n x n complex matrices with A = A* and ||AB - BA||2/(n - 1), then ...
AbstractLet A be a bounded linear operator on a Hilbert space H; denote |A| = (A∗A)12 and the norm o...
AbstractLet H and K be Hilbert spaces, and suppose A ε B(H) and B ε B(K) are self-adjoint operators ...
AbstractIf A ∘ X is the Schur product of n×n matrices A and X, then we study estimates on the norm o...
AbstractThe Fuglede property extends to ∗-hyponormal Banach algebra elements, and certain Banach alg...
The numerical range and the quadratic numerical range is used to study the spectrum of a class of bl...
The numerical range and the quadratic numerical range is used to study the spectrum of a class of bl...
AbstractLet A be an n × n nonsingular real or complex matrix. The best possible upper bound for the ...
Abstract. In this paper an easier proof is obtained of Alexandru Aleman’s extension of an inequality...
AbstractIt is shown that the infimum over all choices of the operator X of the norm of the operator ...
AbstractLet H and K be Hilbert spaces, and suppose A ε B(H) and B ε B(K) are self-adjoint operators ...
AbstractFor a given self-adjoint matrix H with ∥H∥ = 1 and tr(H) = 0, we consider the number γ(H) wh...
AbstractIt is shown that if A and B are n × n complex matrices with A = A∗ and ∥AB − BA∥</ 2ϵ2(n − 1...
Since the late 1960's mathematicians working mainly in the area of quantum field theory have used c...
AbstractFor bounded Hilbert space operators and for all unitarily invariant norms there hold||||A−B|...
It is shown that if A and B are n x n complex matrices with A = A* and ||AB - BA||2/(n - 1), then ...
AbstractLet A be a bounded linear operator on a Hilbert space H; denote |A| = (A∗A)12 and the norm o...
AbstractLet H and K be Hilbert spaces, and suppose A ε B(H) and B ε B(K) are self-adjoint operators ...
AbstractIf A ∘ X is the Schur product of n×n matrices A and X, then we study estimates on the norm o...
AbstractThe Fuglede property extends to ∗-hyponormal Banach algebra elements, and certain Banach alg...
The numerical range and the quadratic numerical range is used to study the spectrum of a class of bl...
The numerical range and the quadratic numerical range is used to study the spectrum of a class of bl...
AbstractLet A be an n × n nonsingular real or complex matrix. The best possible upper bound for the ...
Abstract. In this paper an easier proof is obtained of Alexandru Aleman’s extension of an inequality...
AbstractIt is shown that the infimum over all choices of the operator X of the norm of the operator ...
AbstractLet H and K be Hilbert spaces, and suppose A ε B(H) and B ε B(K) are self-adjoint operators ...
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