共查询到20条相似文献,搜索用时 10 毫秒
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刘明学 《应用泛函分析学报》2000,2(4):328-330
证明关于压缩算子的如下不变子空间定理:如果T是Hilbert空间H上的压缩算子,且集合Z’={λ∈D;存在z∈H,使得‖z‖=1,且‖(λ-T)z‖<1/3(1-‖λ‖}是开单位圆D的控制集,那么T有非平凡的不变子空间,这个定理包含了S.Brown,B.Chevreau,C.fPearcy和B.Beauzamy的两个重要结果作为特殊情况,特别是,为个定理包含了S.Brown等人的Hilbert空间上的每个具有厚谱的压缩算子都有平凡的不变子空间这个重要结果作为特殊情况。 相似文献
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The paper is devoted to investigations of properties of regular Riesz subspaces and connections between regularity and some topological properties. The problem if a topological closure preserves regularity is solved in the class of discrete Riesz spaces. We also characterize Dedekind complete Riesz spaces possessing the same classes of -regular and regular Riesz subspaces Moreover, various examples of regular and non regular Riesz spaces are presented. 相似文献
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《Indagationes Mathematicae》2017,28(5):1109-1110
There is a mistake in the proof of Lemma 4.2 of Ben Amor et al. (2014), and the corrected proof is provided in this Corrigendum note. 相似文献
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刘明学 《应用泛函分析学报》2003,5(1):79-81
得到了关于序列次可分解算子的一个不变子空间定理,推广了H.Mohebi和M.Rajiabalipour在1994年得到的一个不变子空间定理,并且举例说明存在l2上的有界线性算子T。它有无穷多个变子空间,但是它的不变子空间格Lat(T)不丰富。 相似文献
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A Banach space X is Grothendieck if the weak and the weak? convergence of sequences in the dual space X? coincide. The space ?∞ is a classical example of a Grothendieck space due to Grothendieck. We introduce a quantitative version of the Grothendieck property, we prove a quantitative version of the above-mentioned Grothendieck?s result and we construct a Grothendieck space which is not quantitatively Grothendieck. We also establish the quantitative Grothendieck property of L∞(μ) for a σ-finite measure μ. 相似文献
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本文给出了可分无限维Hilbert空间H上有界线性算子全体B(H)中的相似不变子空间的构造,同时给出了B(H)上双边保相似线性映射的表示. 相似文献
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In this paper, the similarity-invariant subspaces of B(H), which is the Banach algebra of all bounded linear operators on a separable infinite-dimensional Hilbert space H, are completely characterized and the representations of bounded linear maps on B(H) which preserve similarity in both directions are given.
Received November 3, 1999, Revised September 20, 2000, Accepted February 5, 2001 相似文献
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Alexander Schmidt 《Mathematische Nachrichten》1999,203(1):159-173
We show that the coarse cohomology, defined by J. ROE for complete metric spaces, coincides with the sheaf cohomology of the constant sheaf IR for a certain Grothendieck topology. Therefore many properties of coarse cohomology are easy consequences of general principles. 相似文献
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Disjointness Preserving Operators on Complex Riesz Spaces 总被引:2,自引:0,他引:2
It is proven that ifE
and F
are complex Riesz spaces and ifT is an order bounded disjointness preserving operator fromE
intoF
, then
This fundamental result of M. Meyer is obtained by elementary means using as the main tool the functional calculus derived from the Freudenthal spectral theorem. It is also shown that ifT is an order bounded disjointness preserving operator, a formula of the form
holds. It implies a polar decomposition of an order bounded disjointness preserving operator as the product of a Riesz homomorphism and an orthomorphism. Results of P. Meyer-Nieberg in this regard are generalized. 相似文献
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研究了算子子空间的渐近自反性问题,渐近自反子空间的遗传斯近自反性以及某些单个算子的渐近自反性.我们也讨论了投影网类的浙近自反性。 相似文献
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Adam Bowers 《Journal of Mathematical Analysis and Applications》2010,369(2):671-677
In this note we develop a notion of integration with respect to a bimeasure μ that allows integration of functions in the projective tensor product , where ν1 and ν2 are Grothendieck measures for μ. This integral, which agrees with the standard notion of integration with respect to a bimeasure, allows us to integrate inner products and provides a generalization of the Grothendieck inequality to a measure-theoretic setting. 相似文献
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For a linear subspace I of a Riesz space there are various well-known properties that are equivalent to I being an ideal, such as I is a full Riesz subspace, I is a solid subspace, I is a Riesz subspace and the kernel of a positive linear map, I is the kernel of a Riesz homomorphism. Generalizations of these properties to partially ordered vector spaces are considered and their relations are investigated. It is shown that for directed subspaces all these generalizations are equivalent, just as in the case of Riesz spaces. 相似文献
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We will give quiver presentations of the Grothendieck constructions of functors from a small category to the 2-category of 𝕜-categories for a commutative ring 𝕜. 相似文献
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证明了一类次可分解算子的不变子空间格是丰富的,并举例说明存在Hilbert空间上的有界线性算子T,它有无穷多个不变子空间,但是它的不变子空间格Lat(T)不丰富. 相似文献
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ABSTRACT A ring R is called generalized Abelian if for each idempotent e in R, eR and (1 ? e)R have no isomorphic nonzero summands. The class of generalized Abelian rings properly contains the class of Abelian rings. We denote by GAERS ? 1 the class of generalized Abelian exchange rings with stable range 1. In this article we prove, by introducing Boolean algebras, that for any R ∈ GAERS ? 1, the Grothendieck group K 0(R) is always an Archimedean lattice-ordered group, and hence is torsion free and unperforated, which generalizes the corresponding results of Abelian exchange rings. Our main technical tool is the use of the ordered structure of K 0(R)+, which provides a new method in the study of Grothendieck groups. 相似文献
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N. Naumann 《Transactions of the American Mathematical Society》2007,359(4):1653-1683
We give sufficient cohomological criteria for the classes of given varieties over a field to be algebraically independent in the Grothendieck ring of varieties over and construct some examples.
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For a topological space X we denote by CL(X) the collection of all nonempty closed subsets of X. Suppose we have a map T which assigns in some coherent way to every topological space X some topology T(X) on CL(X). In this paper we study continuity and inverse continuity of the map iA,X :(CL(A),T{A)) → (CL(X),T(X)) defined by iA,x(F) = F whenever F ∈CL(A), for various assignment T; in particular, for locally finite topology, upper Kuratowski topology, and Attouch-Wets topology, etc. 相似文献
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Let Mφ be the operator of multiplication by φ on a Hilbert space of functions analytic on the open unit disk. For an invariant subspace F for the multiplication operator Mz, we derive some spectral properties of the multiplication operator Mφ : F → F. We characterize norm, spectrum, essential norm and essential spectrum of such operators when F has the codimension n property with n ∈ {1, 2, …, + ∞}. 相似文献