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1.
The strongly irreducible operators in nest algebras   总被引:2,自引:0,他引:2  
An operatorT on is called strongly irreducible ifT does not commute with any nontrivial idempotent operator. In this paper, we first show that each nest algebra ( ) has strongly irreducible operators. Secondly, we obtain a characterization of operators which can be uniquely written as a direct sum of finitely many strongly irreducible operators. Finally, we characterize the strongly irreducibility of operators in a nest algebra ( ).This project was partially supported by National Natural Science Foundation of China.  相似文献
2.
关于Boole语义的真度不变性定理   总被引:2,自引:1,他引:1  
基于B-赋值理论,在B为有限Boole代数的前提下,得出了三个主要结论。首先,讨论了广义Boole函数与Boole函数之间的关系。其次,得出了在有限Boole语义理论意义下的真度不变性定理。最后给出了经典逻辑系统关于有限Boole语义的完备性定理。  相似文献
3.
目标定位最优布站的研究   总被引:1,自引:0,他引:1  
将目标检测问题转化为椭球体的截面对圆的覆盖问题,并给出了“逐层收缩”方案,给出了一个可计算的较优的结果;通过对逐层收缩方案的调整,获得了最优解:18个球(9个红球和9个蓝球).本文将目标定位问题转化为圆的三重覆盖问题,建立“球均定位能力”模型证明了一个红(蓝)球周围有4个蓝(红)球这种模式具有最大的球均定位能力,在此基础上给出红、蓝球的一个布局.36个球(18个红球和18个蓝球).  相似文献
4.
Abstract Let H be a complex seperable Hilbert space and ~(Jt~) denote the collection of bounded linear operators on H. For an operator in L(H), rad{A}' denotes the Jacobson radical of the commutant of A. This paper characterizes the similarity of strongly irreducible operator weighted shift in terms of {A}'/rad{A}'. Moreover, we suggest some ways to determine when an operator weighted shift is strongly irreducible and when its commutant is commutative.  相似文献
5.
设H是一个可分的Hilbert空间,(?)(H)是H上的有界线性算子全体.对 A∈(?)(H),(?)’(A)={B∈(?)(H):AB=BA},rad(?)’(A)表示(?)’(A)的Jacob son根.本文首先举例说明了存在Cowen-Douglas算子T,商代数(?)’(T)/rad(?)’(T) 可以是不交换的.在给出了使得(?)’(T)/rad(?)’(T)交换的充分条件之后,证明了使得 (?)’(T)/rad(?)’(T)交换的Cowen-Douglas算子在Bn(Ω)中是稠密的.对Bmn(Ω),得到了类似的结果。  相似文献
6.
王尧  任艳丽 《数学学报》2006,49(6):1367-137
设M={A=?_(g∈G)A_g,V=?_(g∈G)V_g,W=?_(g∈G)W_g,B=?_(g∈G)B_g}与(,),[,]是一个G-分次Morita Context,且满足(V,W)=A,[W,V]=B,A,B都有单位元.本文证明τG(B):[W,ΥG(A)V]=【WΥc(A),V],ΥG(A)=(V,ΥG(B)W)=(VΥG(B),W)其中ΥG代表P_G(分次素根),J_G(分次Jacobson根),K_G(分次Koethe根),L_G(分次Levitzki根)和s_G(分次强素根),us_G(分次一致强素根).  相似文献
7.
An operator on a complex, separable, infinite dimensional Hilbert space is strongly irreducible if it does not commute with any nontrivial idempotent. This article answers the following questions of D. A. Herrero: (i) Given an operatorT with connected spectrum, can we find a strongly irreducible operatorL such that they have same spectral picture? (ii) When we use a sequence of irreducible operators to approximateT, can the approximation be the “most economic”? i.e., does there exist a strongly irreducible operatorL such thatTS(L) (the closure of the similarity orbit ofL)? It is shown that the answer for the two questions is yes.  相似文献
8.
以林县粮食中常见的霉菌如白地霉、土曲霉等接种于玉米面饼上,培养数日后,加一定量亚硝酸钠,即可产生亚硝胺,其中经高分辨GC-MS证实,有N-3-甲基丁基-N-1-甲基丙酮基亚硝胺,我们又通过化学合成MAMBNA加以验证,证明化学合成的MAMBNA与霉变玉米面饼中分离的MAMBNA结构完全一致,本文对产生这种新亚硝胺的物质基础和其在食管癌高发区中的意义进行了讨论。  相似文献
9.
In this paper we investigate Jordan homomorphisms of upper triangular matrix rings and give a sufficient condition under which they are necessarily homomorphisms or anti-homomorphisms.  相似文献
10.
We derive a sharp nonasymptotic bound of parameter estimation of the L1/2 regularization. The bound shows that the solutions of the L1/2 regularization can achieve a loss within logarithmic factor of an ideal mean squared error and therefore underlies the feasibility and effectiveness of the L1/2 regularization. Interestingly, when applied to compressive sensing, the L1/2 regularization scheme has exhibited a very promising capability of completed recovery from a much less sampling information. As compared with the Lp (0 〈 p 〈 1) penalty, it is appeared that the L1/2 penalty can always yield the most sparse solution among all the Lv penalty when 1/2 〈 p 〈 1, and when 0 〈 p 〈 1/2, the Lp penalty exhibits the similar properties as the L1/2 penalty. This suggests that the L1/2 regularization scheme can be accepted as the best and therefore the representative of all the Lp (0 〈 p 〈 1) regularization schemes.  相似文献
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