On the J-Normal Extensions of Operators

A bounded linear operator T acting on a Hilbert space H is said to be J- subnormal with order n if on some \Pi _n-Pontrjagin space \Pi containing H, there exists a bounded J-normal operator \tilde T such that \tilde Tf=Tf for every f in H and that \Pi is spanned by the elements of the form $\tilde T^{*k}f$, where f \in H and k = 0, 1, 2,\cdots. Let H be a Hilbert space and let I7 be in B(H). The main purpose of this paper is to prove that the following statements are equivalent: (1) Tis J-subnormal with order n; (2) For each non-negative integer r and for each set {x_ik: i, k = 0, 1,\cdots, r} of elements of H, the Hermitian form $\sum\limits_{i,j,k,l=0}^r(T^jx_ik,T^ix_jl)\alpha_ik\bar \alpha_jl$ has at most n negative squares, and for at least one choice of r and {x_ik}, it has exactly n negative squares; (3) The operator function is quasi-positive befinite with order n in the complex plane. This result is an extension of the theorems of Halmos and Bram,     

$(m,n)$-Igusa-Todorov 代数,IT-维数和三角矩阵代数

设$T$, $U$是两个Artin代数, $_U M_T$是$U$-$T$-双模.本文得到了三角矩阵代数$\Lambda=\left({\smallmatrix T&0\\ M&U \endsmallmatrix}\right)$是$(m,n)$-Igusa-Todorov的一个充要条件.我们还研究了$\Lambda$的IT维数.更具体地说,事实证明$$\max\{\ITdim T, \ITdim U\}\leqslant\ITdim \Lambda\leqslant\min\{\max\{\gldim T,\ITdim U\},\max\{\gldim U,\ITdim T\}\}.$$     

FM Space Depend on Operator T and the Normal Solvability of Operator Polynomial P（T）

ＦＭ　Ｓｐａｃｅ　Ｄｅｐｅｎｄ　ｏｎ　Ｏｐｅｒａｔｏｒ　Ｔ　ａｎｄ　ｔｈｅ　Ｎｏｒｍａｌ　Ｓｏｌｖａｂｉｌｉｔｙ　ｏｆ　Ｏｐｅｒａｔｏｒ　Ｐｏｌｙｎｏｍｉａｌ　Ｐ（Ｔ）ＦＭＳｐａｃｅＤｅｐｅｎｄｏｎＯｐｅｒａｔｏｒＴａｎｄｔｈｅＮｏｒｍａｌＳｏｌｖａ...     

不同权Bloch型空间之间的加权Cesàro 算子

该文讨论了$\a$-Bloch空间$\ba$和对数Bloch空间$\bl$之间的加权Ces\'aro算子$\tg$的有界性和紧性,给出$\tg$是$\ba$到$\bl$的有界算子或紧算子的充要条件和$\tg$是$\bl$到$\ba$的有界算子或紧算子的充要条件.     

BMOA空间与Bloch型空间之间的加权Ces\''{a}ro算子

本文研究单位圆盘上的BMOA空间和$\a$-Bloch型空间之间的加权 Ces\'{a}ro 算子,给出了$\tg$是BMOA空间到$\ba$空间的有界算子或紧算子的充分必要条件.     

代数κ-拟-A类算子的Weyl定理

若T或T~*是无穷维可分的Hilbert空间H上的代数κ-拟-A类算子,则Weyl定理对任意的f∈H(σ(T))成立,其中H(σ(T))为σ(T)的开邻域上解析函数的全体.若T~*是代数κ-拟-A类算子,则a-Weyl定理对f(T)成立。还证明了若T或T~*是代数κ-拟-A类算子,则Weyl谱与本质近似点谱的谱映射定理对f(T)成立.     

奇异积分算子交换子在变指数空间上的特征

The main purpose of this paper is to characterize the Lipschitz space by the boundedness of commutators on Lebesgue spaces and Triebel-Lizorkin spaces with variable exponent.Based on this main purpose, we first characterize the Triebel-Lizorkin spaces with variable exponent by two families of operators. Immediately after, applying the characterizations of TriebelLizorkin space with variable exponent, we obtain that b ∈■β if and only if the commutator of Calderón-Zygmund singular integral operator is bounded, respectively, from■ to■,from■ to■ with■. Moreover, we prove that the commutator of Riesz potential operator also has corresponding results.     

Theorems on imbedding in anisotropic spaces of vector-valued functions

Imbedding theorems are proved for abstract anisotropic spaces of Sobolev type. In particular, it is proved that if G is a bounded set satisfying thel horn condition, then there holds the imbedding where , H is a Hilbert space, and A is a self-adjoint positive operator.Translated from Matematicheskie Zametki, Vol. 22, No. 2, pp. 297–301, August, 1977.     

COMMUTATORS OF MULTIPLIERS ON HARDY SPACES

Let T be the multiplier operator associated to a multiplier m, and [b, T] be the commutator generated by T and a BMO function b. In this paper, the authors have proved that [b,T] is bounded from the Hardy space H^1（R^n） into the weak L^1 （R^n） space and from certain atomic Hardy space Hb^1 （R^n） into the Lebesgue space L^1 （R^n）, when the multiplier m satisfies the conditions of Hoermander type.     

非线性Lipschitz算子的Lipschitz对偶算子及其应用

在文山中我们对非线性Ｌｉｐｓｃｈｉｔｚ算子定义了其Ｌｉｐｓｃｈｉｔｚ对偶算子，并证明了任意非线性Ｌｉｐｓｃｈｉｔｚ算子的Ｌｉｐｓｃｈｉｔｚ对偶算子是一个定义在Ｌｉｐｓｃｈｉｔｚ对偶空间上的有界线性算子．本文还进一步证明：设Ｃ为 Ｂａｎａｃｈ空间 Ｘ的闭子集，Ｃ＊Ｌ为Ｃ的 Ｌｉｐｓｃｈｉｔｚ对偶空间，Ｕ为 Ｃ＊Ｌ上的有界线性算子，则当且仅当 Ｕ为 ｗ＊－ｗ＊连续的同态变换时，存在Ｌｉｐｓｃｈｉｔｚ连续算子Ｔ，使Ｕ为Ｔ的Ｌｉｐｓｃｈｉｔｚ对偶算子．这一结论的理论意义在于：它表明一个非线性Ｌｉｐｓｃｈｉｔｚ算子的可逆性问题可转化为有界线性算子的可逆性问题．作为应用，通过引入一个新概念──ＰＸ－对偶算子，在一般框架下给出了非线性算子半群的生成定理．     

一类次线性算子在广义Morrey空间上的加权有界性

本证明了如果次线性算子T在Orlicz空间上有介,则也有Morrey空间上有界,该算子包括极大算子和奇异积分算子等重要算子。     

$\mathbb{C}^N$上的Fock空间上可逆加权复合算子的注记

本文表明$\mathbb{C}^N$上的Fock空间上有界可逆加权复合算子是酉算子的非零常数倍,这是关于$\mathbb{C}^N$上的Fock空间上可逆加权复合算子已有刻画的一个补充,也是对$\mathbb{C}$上的Fock空间上相应结果的推广.     

Li–Yorke chaos translation set for linear operators

In order to study Li–Yorke chaos by the scalar perturbation for a given bounded linear operator T on a Banach space X, we introduce the Li–Yorke chaos translation set of T, which is defined by \(S_{LY}(T)=\{\lambda \in {\mathbb {C}};\lambda +T \text { is Li--Yorke chaotic}\}\). In this paper, some operator classes are considered, such as normal operators, compact operators, shift operators, and so on. In particular, we show that the Li–Yorke chaos translation set of the Kalisch operator on the Hilbert space \(\mathcal {L}^2[0,2\pi ]\) is a simple point set \(\{0\}\).     

New Studies on the Fock Space Associated to the Generalized Airy Operator and Applications

In this work, we introduce the Fock space \(F_\nu (\mathbb {C})\) associated to the Airy operator \(L_\nu \), and we establish Heisenberg-type uncertainty principle for this space. Next, we study the Toeplitz operators, the Hankel operators and the translation operators on this space. Furthermore, we give an application of the theory of extremal function and reproducing kernel of Hilbert space, to establish the extremal function associated to a bounded linear operator \(T{:}\,F_\nu (\mathbb {C})\rightarrow H\), where H be a Hilbert space. Finally, we come up with some results regarding the extremal functions, when T is the difference operator and the Dunkl-difference operator, respectively.     

Composition Cesàro Operator on the Normal Weight Zygmund Space in High Dimensions

Let n>1 and B be the unit ball in n dimensions complex space Cⁿ.Suppose thatφis a holomorphic self-map of B andψ∈H(B)withψ(0)=0.A kind of integral operator,composition Cesàro operator,is defined by T_φψ(f)(z)=∫¹0f[φ(tz)]Rψ(tz)dt/t,f∈(B)z∈B.In this paper,the authors characterize the conditions that the composition Cesàro operator T_φ,ψis bounded or compact on the normal weight Zygmund space Z_μ(B).At the same time,the sufficient and necessary conditions for all cases are given.     

On boundedness of the hardy and bellman operators in the spaces h and bmo

Hardy (1919) proved that the space L^p(T), 1 ? p ? ∞, is invariant under (C, 1)- transformation of Fourier coefficients. This transformation may be considered as a linear integral operator H: L^p(T) → L^p(T), 1 ? p ? ∞. In this paper we show that the operator H is unbounded in the space BMO(T) of periodic functions of bounded mean oscillation. For the conjugate operator B introduced by Bellman (1944) B: L^q(T) → L^q(T), 1/ρp + 1/rho;q = 1, the boundedness of B in BMO(T) is proved directly without duality argument. An example is given to show that B is unbounded in H(T).     

$\mathbb{C}^{n}$中$\mu$-Bergman空间的刻画和微分复合算子

设$p>0$, $\mu$和$\mu_{1}$是$[0,1)$上的正规函数. 本文首先给出了$\mathbb{C}^{n}$中单位球上$\mu$-Bergman空间$A^{p}(\mu)$的几种等价刻画; 然后 分别刻画了$A^{p}(\mu)$到$A^{p}(\mu_{1})$的 微分复合算子$D_{\varphi}$为有界算子以及紧算子的充要条件, 同时给出了当$p>1$时$D_{\varphi}$为 $A^{p}(\mu)$到$A^{p}(\mu_{1})$上紧算子的一种简捷充分条件和必要条件.     

Lipschitz Estimates for Commutators of $N$-Dimensional Fractional Hardy Operators

In this paper, it is proved that the commutator$\mathcal{H}_{β,b}$ which is generated by the $n$-dimensional fractional Hardy operator $\mathcal{H}_β$ and $b\in \dot{Λ}_α(\mathbb{R}^n)$ is bounded from $L^P(\mathbb{R}^n)$ to $L^q(\mathbb{R}^n)$, where $0<α<1,1相似文献   

Banach 空间中极大单调算子扰动的值域

设X为实Banach空间, T:D(T)(?)X→2X*为极大单调算子, C: D(T)(?)X→X*为有界算子(未必连续),而C(T+J)-1为紧算子．本文在上述假设条件下,通过附加一定的边界条件应用Leray-Schauder度理论研究了下述包含关系:0∈(T+C)(D(T)∩ BQ(0)),0∈(T+C)(D(T)∩ BQ(0));以及S(?)R(T+C), intS(?)intR(T+C)(其中S(?) X*);B+D(?)R(T+C),int(B+D)(?)intR(T+C)(其中 B(?)X*,D(?)X*)的可解性,得出了一些新的结论．