Ferna´ndez, Absence of point spectrum for unitary operators, J. Differential Equations 244 (2008), no. 2, 229-241.M. A. Astaburuaga, O. Bourget, V. Corte´s and C. Ferna´ndez. Absence of point spectrum for unitary operators. J. Differential Equations 244(2): 229-241, ...
Operators which are similar to unitary operators with absolutely continuous spectrumIn recent years a series of papers [1]-[3] have beendevotedto clarifying the conditions under which a contraction operator T (II T II-~ 1) is similar to a unitary operator. In the paper of B. Nagy and C...
由于\mathbf{R}_x 是半正定的,因此这样的解始终存在,但它不是唯一的:如果 \boldsymbol{\Phi} 是一个解,那么 \tilde{\Phi}=\boldsymbol{\Phi} \mathbf{U}也是一个解,其中 U 是任意的幺正算子(arbitrary unitary operator)(即\mathrm{UU}^{+}=\mathrm{I},I是恒等算子)。 因此,(8) 中定义的 ES ...
for magnetic quantum graphs on the square lattice. the quantum graph nature of the differential operators causes, besides the contribution of the tight-binding operator to the continuous spectrum, a contribution to the point spectrum that consists of dirichlet eigenfunctions vanishing at every vertex. ...
It is well known thatAadmits a unique decomposition into a direct sum of three self-adjoint operatorsAp,AacandAscsuch that there exists an orthonormal basis of eigenvectors for the operatorAp, the operatorAachas purely absolutely continuous spectrum and the operatorAschas purely singular continuous ...
Using ⁎UφU⁎ instead of φ for an appropriate unitary operator U:K→H, the statements of Theorem 2.1, Theorem 2.2 can be reduced to the case when H=K and h0=k0. Although, the fact that “H and K are isomorphic” is one of the conclusions of the main results. (2) We ...
In a unitary Banach algebra conditions are sought for an element, the spectrum of which is the singleton {1}, to be the identity of the algebra. Our main result is that this is true if the element is Abel bounded and doubly (N)-uniformly Abel bounded. This condition is fulfilled if ...
It is well known that Schrödinger operator is unitary equivalent to the Dirichlet operator of the ground state measure, whenever the infimum of its spectrum is actually an eigenvalue. Moreover, the Ma R Carmona - 《Lecture Notes in Mathematics》 被引量: 26发表: 1979年 ...
for all if and only if there exist a unitary operator and a scalar c∈ {−1,1} such that either (1) Φ(A) = cUAU* for every , or (2) Φ(A) = cUAtU* for every . Here At is the transpose of A with respect to an arbitrary but fixed orthonormal basis of H1. Moreov...
A note on Browder spectrum of operator matrices When A ∈ B ( H ) and B ∈ B ( K ) are given, we denote by M C the operator acting on the Hilbert space H ⊕ K of the form M C = ( A C 0 B ). In this note,... S Zhang,H Zhong - 《Journal of Mathematical Analysis &...