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1.
杨大春 《数学季刊》1991,6(2):103-108
L.K.Chen[1]中研究了一类沿曲面的奇异积分算子: 其中为径向。上的0次齐次函数,且,1相似文献   

2.
本文给出了Hamilton算子和Laplace算子间的一个积分公式,并指出文献[1]中的一个错误.  相似文献   

3.
61.IntroductionThefixedPOinttheoremsofmixedmonotoneoperatorsaregotinpaper[1jandF2j-Inthispaper,regularconeanddemicontinuousofoperatorareweakenedinTheorem1ofpaper[1j.Theformerisweakenedtonormalconeandthelattertoweakerandweakercontinuous.Separabilityandweaklysequentiallycompactofimagesetofoperatorareweakenedtoquasi-separabilityandquasiweaklysequentiallycompactinTheorem1ofpaper[2j,Westillget'thefixedpointtheoremsofmixedmonotoneoperators.Wea1sogiveson1eapplicationstono11-monoteoperatorsanddiffe…  相似文献   

4.
C_2(H)上初等算子的拟正常性   总被引:5,自引:1,他引:4  
李刚 《数学学报》1989,32(2):219-224
本文主要给出了 C_2(H)上初等算子 X(?)AXB+MXN 为拟正常的充要条件,其中{A,M}、{B,N}分别为双交换有界线性算子.作为推论,给出了[1]中相应的结果.  相似文献   

5.
项一星 《大学数学》2001,17(1):9-11
本文讨论了Bergman空间L1α(Ω)中Toeplitz和Hankel算子的W*紧性,得到与L2μ(Ω)上T-H算子紧性[4]类似的某些结果.  相似文献   

6.
关于复值解析函数Riesz—Dunford积分的Ky Fan定理由[1]推广到算子值解析函数,由此函数论中的很多定理得到了推广.本文的目的在于改进[1]中的结果,得到了较弱条件下的Pick定理,从而推广了[2]中的Julia引理,并简化了其证明过程.  相似文献   

7.
1.IntroductionInthepresentpaper,wewillcontinuethestudyofHilbertmodules[1-5].LetHbeaHilbertspaceandAafunctionalgebra.WesaythatHisaHilbertmoduleoverAifthereisamultiplication(a,f)-affromAxHtoH,makingHintoanXmoduleandif,inaddition,theactionisjointlycontinuousinthesup-normonAandtheHilbertspacenormonH.ThecategoryHofallHilbertNmodulesisanaturalsettingfornumerousquestionsinoperatortheory.In[9],DouglasandPaulseninitiatedasystematicstudyofHilbertmodules'theywereabletotranslatemanyconceptsandpro…  相似文献   

8.
《数学学报》2004,47(1):79-86
设p≥0且A,B是Hilbert空间上两个正算子,Furuta给出若A≥B>0,那么对任意r≥0,F(α)=(ArBαAr)p+2r/α+2r是关于α≥p单调递减的,但是他指出这个结果在0≤α≤p和r≥0的条件下并不一定成立.本文给出(1)如果-1/2<r<0且p<-2r,那么F(α)在[-p-4r,+∞)及(-∞,p]上单调递减,并且这两个区间不能扩大;(2)如果-1/2<r<0且p>-2r,那么F(α)在(-∞,-p-4r]及[p,+∞)上单调递增,并且这两个区间不能扩大;(3)如果r>0,p>0,那么[p,+∞)也是F(α)的最佳单调区间.  相似文献   

9.
设p>0且A,B是Hilbert空间上两个正算子,Furuta给出若A>B>0,那么对任意r>0,F(α)=(ArBαAr)p+2r/α+2r 是关于α>P单调递减的,但是他指出这个结果在0<α0的条件下并不一定成立.本文给出: (1)如果-1/2-2r,那么F(α)在(-∞,-P-4r]及[p,+∞)上单调递增,并且这两个区间不能扩大; (3)如果r>0,P>0,那么[p,+∞)也是F(α)的最佳单调区间.  相似文献   

10.
经典Volterra算子$V$及其伴随算子$V^*$在复空间$L^2[0,1]$中起着关键作用. 关于$V$和$V^*$的线性组合的性质, 我们给出了确保$z_1V+z_2V^*(z_1,z_2\in\mathbb{C})$满足增生性质的等价条件. 本文描述了$(u+iv)I+mV+nV^*(u,v,m,n\in\mathbb{R},m+n\geq0)$数值域的精确表示.  相似文献   

11.
研究多维Cardaliguet-Eurrard型神经网络算子的逼近问题.分别给出该神经网络算子逼近连续函数与可导函数的速度估计,建立了Jackson型不等式.  相似文献   

12.
Structure of the spectrum of infinite dimensional Hamiltonian operators   总被引:3,自引:0,他引:3  
This paper deals with the structure of the spectrum of infinite dimensional Hamiltonian operators.It is shown that the spectrum,the union of the point spectrum and residual spectrum,and the continuous spectrum are all symmetric with respect to the imaginary axis of the complex plane. Moreover,it is proved that the residual spectrum does not contain any pair of points symmetric with respect to the imaginary axis;and a complete characterization of the residual spectrum in terms of the point spectrum is then given.As applications of these structure results,we obtain several necessary and sufficient conditions for the residual spectrum of a class of infinite dimensional Hamiltonian operators to be empty.  相似文献   

13.
In this paper,the technique of approximate partition of unity is used to construct a class of neural networks operators with sigmoidal functions.Using the modulus of continuity of function as a metric,...  相似文献   

14.
The paper deals with a general class of linear positive approximation processes designed using series. For continuous and bounded functions defined on unbounded interval we give rate of convergence in terms of the usual modulus of smoothness. The main goal is to identify functions for which these operators provide uniform approximation over unbounded intervals. Particular cases are delivered.  相似文献   

15.
在齐型空间上讨论由分数次积分算子、奇异积分算子及BMO函数所构成的几类Toeplitz型算子的有界性.  相似文献   

16.
In this paper the new concept of totally omnipresent operators is introduced. These operators act on the space of holomorphic functions of a domain in the complex plane. The concept is more restrictive than that of strongly omnipresent operators, also introduced by the authors in an earlier work, and both of them are related to the existence of functions whose images under such operators exhibit an extremely wild behaviour near the boundary. Sufficient conditions for an operator to be totally omnipresent as well as several outstanding examples are provided. After extending a statement of the first author about the existence of large linear manifolds of hypercyclic vectors for a sequence of suitable continuous linear mappings, it is shown that there is a dense linear manifold of holomorphic monsters in the sense of Luh, so completing earlier nice results due to Luh and Grosse-Erdmann.  相似文献   

17.
解析函数的Banach空间上之复合算子   总被引:2,自引:0,他引:2  
曹广福  余大海 《数学学报》1998,41(2):235-240
本文研究了一类解析函数的Banach空间X上之复合算子,这类空间包含了Bloch空间,并且可看作Bergman空间L1a(D)中具有原子分解的解析函数的对偶空间.我们刻划了这类空间上紧复合算子及Fredholm复合算子的特征,此外,还研究了具有闭值域的复合算子.  相似文献   

18.
In this paper, we consider questions related to the structure of inverse matrices of linear bounded operators acting in infinite-dimensional complex Banach spaces. We obtain specific estimates of elements of inverse matrices for bounded operators whose matrices have a special structure. Matrices are introduced as special operator-valued functions on an index set. The matrix structure is described by the behavior of the given function on elements of a special partition of the index set. The method used for deriving the estimates is based on an analysis of Fourier series of strongly continuous periodic functions.  相似文献   

19.
将经典“试探函数组”1,x,x^2应用于扩展乘数法,建立了一个判别线性正算子能否改造为逼近任何无界连续函数的充要条件。利用该条件给出了一类变形的插值多项式算子的收敛性定理,得到了具有一般性的结论。  相似文献   

20.
On standard measure spaces every order continuous linear map between two ideals of almost everywhere finite measurable functions can be represented by a random measure. An analogue of this theorem is proved for the case of arbitrary σ-finite measure spaces. This fact leads to a proof that every order continuous linear map between ideals of almost everywhere finite measurable functions on σ-finite measure spaces is multiplication conditional expectation representable. This sheds further light on the structure of order continuous operators. Mathematics Subject Classification (20000): 47B38, 47B65 J.J. Grobler-Financial assistance of the NRF is gratefully acknowledged. D.T. Rambane-Financial assistance of the University of Venda research fund is gratefully acknowledged.  相似文献   

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