共查询到20条相似文献,搜索用时 956 毫秒
1.
本文研究某些加权复合算子之非平凡不变子空间的存在性.特别地,证明了每个亚正规加权复合算子均有非平凡的不变子空间并且提出了一个新概念,称其为本性可逆变换.对于概率空间上本性可逆变换所确定的加权复合算子,给出其非平凡不变子空间存在性的一个等价刻画. 相似文献
2.
严克任 《数学年刊A辑(中文版)》1988,(5)
一族次正常算子如有相互可交换的正常扩张,则称作为联合次正常算子族。本文通过引进无限维空间上测度的部分Cauchy变换的概念,建立了部分Cauchy变换与有限维柱集上的分布的方程,利用Thomson技巧,证明了联合次正常算子族必有公共的非平凡不变子空间。作为应用,得到了单个次正常算子的限制代数的非平凡的不变子空间的存在性。最后,在具有循环元的情形,证明了联合次正常算子族的超不变子空间的存在性。 相似文献
3.
伍镜波 《数学年刊A辑(中文版)》1984,(6)
本文证明n阶J-次正常算子在一个亏维数不超过n的不变子空间的限制是次正常算子,且当n>O时这类算子有非平凡超不变子空间。由此易知J-次正常算子有非平凡不变子空间。我们还讨论了拟幂零的和紧的J-次正常算子。 相似文献
4.
童裕孙 《数学年刊A辑(中文版)》1984,(5)
在本文中,我们引入了Krein空间上K拟三角算子的概念,讨论了这类算子的一些代数性质,并在适当的条件下,证明了这类算子在其极大半定不变子空间上的限制存在非平凡的不变子空间。 相似文献
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本文给出了单位球上加权Bergman空间上的加权复合算子的本性范数,并刻画了这类加权复合算子的有界性和紧性. 相似文献
7.
关于可分解算子的扰动的不变子空间(英文) 总被引:1,自引:0,他引:1
刘明学 《应用泛函分析学报》1999,(3)
在文献[1]中,J.Eschmeier和B.Prunaru证明了(复)Banach空间上的每个具有Bishop性质(β)和浓厚谱的有界线性算子有非平凡的不变子空间.在文献[2]中,H.Mohebi和M.Radjabalipour在减弱算子的Bishop性质(β)和加强谱的浓厚性条件的情况下得到了另外几个不变子空间定理.本文给出了一个更进一步的不变子空间定理(见定理1). 相似文献
8.
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
9.
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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在共振点附近的一类二阶泛函微分方程的解析解 总被引:3,自引:0,他引:3
在复域C内研究一类包含未知函数迭代的二阶微分方程x″(z)=G(z,x(z),x~2(z),…,x~m(z))解析解的存在性.通过Schr(?)der变换,即x(z)=y(αy~(-1)(z)),把这类方程转化为一种不含未知函数迭代的泛函微分方程α~2y″(αz)y″(z)-αy′(αz)y″(z)= (y′(z))~3G(y(z),y(αz),…,y(α~mz)),并给出它的局部可逆解析解.本文不仅讨论了双曲型情形0<|α|<1和共振的情形(α是一个单位根),而且还在Brjuno条件下讨论了共振点附近的情形(即单位根附近). 相似文献
13.
Classification of Positive Ground State Solutions with Different Morse Indices for Nonlinear N-Coupled Schr(o)dinger System 下载免费PDF全文
In this paper,we study the following N-coupled nonlinear Schr(o)dinger sys-tem{-△uj+ uj =μju3j + ∑i≠jβi,ju3iuj,in Rn,uj>0 in Rn,uj(x)→0 as |x|→+∞,j=1,…,N,where n ≤ 3,N ≥ 3,μj > 0,βi,j =βj,i > 0 are constants and βj,j =μj,j =1,…,N.There have been intensive studies for the system on existence/non-existence and clas-sification of ground state solutions when N =2.However fewer results about the classification of ground state solution are available for N ≥ 3.In this paper,we first give a complete classification result on ground state solutions with Morse indices 1,2 or 3 for three-coupled Schr(o)dinger system.Then we generalize our results to N-coupled Schr(o)dinger system for ground state solutions with Morse indices 1 and N.We show that any positive ground state solutions with Morse index 1 or Morse index N must be the form of (d1w,d2w,…,dNw) under suitable conditions,where w is the unique positive ground state solution of certain equation.Finally,we generalize our results to fractional N-coupled Schr(o)dinger system. 相似文献
14.
This paper studies the solution of the spectral factorization problem for multivariable distributed parameter systems with an impulse response having an infinite number of delayed impulses. A coercivity criterion for the existence of an invertible spectral factor is given for the cases that the delays are a) arbitrary (not necessarily commensurate) and b) equally spaced (commensurate); for the latter case the criterion is applied to a system consisting of two parallel transmission lines without distortion. In all cases, it is essentially shown that, under the given criterion, the spectral density matrix has a spectral factor whenever this is true for its singular atomic part, i.e. its series of delayed impulses (with almost periodic symbol). Finally, a small-gain type sufficient condition is studied for the existence of spectral factors with arbitrary delays. The latter condition is meaningful from the system theoretic point of view, since it guarantees feedback stability robustness with respect to small delays in the feedback loop. Moreover its proof contains constructive elements. 相似文献
15.
Stephen Lack 《Journal of Pure and Applied Algebra》2012,216(3):593-597
Many categorical axioms assert that a particular canonically defined natural transformation between certain functors is invertible. We give two examples of such axioms where the existence of any natural isomorphism between the functors implies the invertibility of the canonical natural transformation. The first example is distributive categories, the second (semi-)additive ones. We show that each follows from a general result about monoidal functors. 相似文献
16.
We construct the auto-Schlesinger transformations for all equations in the known list of integrable relativistic Toda chains. Our construction is essentially based on the equations being Lagrangian and on a standard transition to their Hamiltonian form; in this case, the transition is described by the changes of variables that are invertible but not pointwise. We discuss two examples of another type that has similar properties; these are also integrable Lagrangian equations allowing the Schlesinger transformation. 相似文献
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Summary The question considered is the following: If two invertible measure preserving point transformations commute, in what sense is one a function of the other? The main theorem is the following: If two invertible measure preserving transformations commute, and if the first admits of approximation by periodic transformations, then the second transformation is a piecewise power of the first, where we say that is a piecewise power of if there exists a sequence [j(n)] of positive integers such that for each measurable set A the limit of the measure of the symmetric difference of (A) and
j(n)
(A) tends to zero.Research supported in part by NSF grant GP-3752. 相似文献
18.
G. A. Noskov 《Mathematical Notes》1975,17(2):165-168
We describe the automorphisms of group GLn+(o), where (o) is a commutative ring with unity and with an invertible element 2, not generated by the divisors of zero, while the space Max (o) is Noetherian of dimension ≤ n?2. 相似文献
19.
Aurel I. Stan 《Journal of Theoretical Probability》2011,24(1):39-65
The paper is divided into two parts. In the first part we lay down the foundation for defining the joint annihilation–preservation–creation
decomposition of a finite family of not necessarily commutative random variables, and show that this decomposition is essentially
unique. In the second part we show that any two, not necessarily commutative, random variables X and Y for which the vector space spanned by the identity and their annihilation, preservation, and creation operators equipped
with the bracket given by the commutator forms a Lie algebra are equivalent up to an invertible linear transformation to two
independent Meixner random variables with mixed preservation operators. In particular, if X and Y commute, then they are equivalent up to an invertible linear transformation to two independent classic Meixner random variables.
To show this we start with a small technical condition called “non-degeneracy”. 相似文献
20.
R. Shantaram William L. Harkness 《Annals of the Institute of Statistical Mathematics》1970,22(1):181-184
Summary A certain transformation of distribution functions (d.f.'s) of positive random variables (r.v.'s) has been studied by the
author and Harkness in [2] and [3]. In this paper, a limit theorem concerning such a transform of convolutions of d.f.'s is
proved. 相似文献