The Schur–Horn theorem for operators with three point spectrum
نویسندگان
چکیده
منابع مشابه
The Schur-horn Theorem for Operators with Finite Spectrum
We characterize the set of diagonals of the unitary orbit of a self-adjoint operator with a finite spectrum. Our result extends the Schur-Horn theorem from a finite dimensional setting to an infinite dimensional Hilbert space, analogous to Kadison’s theorem for orthogonal projections [17, 18], and the second author’s result for operators with three point spectrum [16].
متن کاملSome Schrödinger Operators with Dense Point Spectrum
Given any sequence {En}n−1 of positive energies and any monotone function g(r) on (0,∞) with g(0) = 1, lim r→∞ g(r) = ∞, we can find a potential V (x) on (−∞,∞) so that {En}n=1 are eigenvalues of − d 2 dx2 + V (x) and |V (x)| ≤ (|x| + 1)−1g(|x|). In [7], Naboko proved the following: Theorem 1. Let {κn}∞n=1 be a sequence of rationally independent positive reals. Let g(r) be a monotone function o...
متن کاملOn the Point Spectrum of Positive Operators
1. Recently, G.-C. Rota proved the following result: Let (S, 2, p) be a measure space of finite measure, P a positive linear operator on Lx(S, 2, u) with Li-norm and L„-norm at most one. If a, | a\ = 1, is an eigenvalue of P such that af=Pf (JELx), then a2 is an eigenvalue such that a2|/|g"=P(|/|g"), where/=|/|g. It can be added that an|/|gn = P(|/|gn) for every integer n; thus Rota proved for ...
متن کاملDiagonals of Self-adjoint Operators with Finite Spectrum
Given a finite set X ⊆ R we characterize the diagonals of self-adjoint operators with spectrum X. Our result extends the SchurHorn theorem from a finite dimensional setting to an infinite dimensional Hilbert space analogous to Kadison’s theorem for orthogonal projections [8, 9] and the second author’s result for operators with three point spectrum [7].
متن کاملThe Spectral Mapping Theorem for Joint Approximate Point Spectrum
The spectral mapping theorem for joint approximate point spectrum is proved when A is an «-tuple of commuting operators on a Banach space and ƒ is any w-tuple of rational functions for which f (A) is defined. The purpose of the paper is to show how properties of parts of the joint spectrum can be obtained by use of spaces of sequences of vectors. The method (first used for general Banach spaces...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Functional Analysis
سال: 2013
ISSN: 0022-1236
DOI: 10.1016/j.jfa.2013.06.024