张量对称类上诱导算子的y-数值半径(英文)

本文研究了诱导矩阵K(A)的y-数值半径ry(K(A))、y-可分数值半径ryχ(K(A))与范数A2、广义矩阵函数dχG(A)之间的关系问题.利用ry(K(A))及ryχ(K(A))的概念,得到了ry(K(A))、ryχ(K(A))、‖A‖2、dGχ(A)它们之间的两个不等式.     

几类特殊的BCI代数

本文给出具有散子代数的ＢＣＩ代数的条件，讨论了Ｌ（Ｘ）为Ｘ的理想的ＢＣＩ代数，完全刻划了每个子代数都是理想的ＢＣＩ代数。     

ON WEIGHT MODULES OF ALGEBRAS OF TWISTED DIFFERENTIAL OPERATORS ON THE PROJECTIVE SPACE

We classify blocks of categories of weight and generalized weight modules of algebras of twisted differential operators on ? ⁿ . Necessary and sufficient conditions for these blocks to be tame and proofs that some of the blocks are Koszul are provided. We also establish equivalences of categories between these blocks and categories of bounded and generalized bounded weight Open image in new window -modules in the cases of nonintegral and singular central character.     

TOEPLITZ OPERATORS AND ALGEBRAS ON DIRICHLET SPACES

The automorphism group of the Toeplitz C-algebra,J(C~1),generated by Toeplitz op-erators with C~1-symbols on Dirichlet space D is discussed;the K_0,X_1-groups and the firstcohomology group of J(C~1)are computed.In addition,the author provs that the spectraof Toeplitz operators with C~1-symbols are always connected,and discusses the algebraic prop-erties of Toeplitz operators.In particular,it is proved that there is no nontrivial selfadjointToeplitz operator on D and T_φ~*=T_φ if and only if T_φ is a scalar operator.     

COMPOSITION OPERATORS ON ANALYTIC VECTOR-VALUED NEVANLINNA CLASSES

Let φ be an analytic self-map of the complex unit disk and X a Banach space. This paper studies the action of composition operator Cφ： f→foφ on the vector-valued Nevanlinna classes N（X） and Na（X）. Certain criteria for such operators to be weakly compact are given. As a consequence, this paper shows that the composition operator Cφ is weakly compact on N（X） and Na（X） if and only if it is weakly compact on the vector-valued Hardy space H^1 （X） and Bergman space B1（X） respectively.     

CHARACTERIZATIONS OF SOME MATRIX CLASSES OF QUASI-HOMOGENEOUS OPERATORS

In this paper,we give a general characterization of a class of matrices of quasi-homogeneous operators between topological vector spaces.     

CSL代数中的有限秩算子 Ⅲ

In terms of the exactly nonzero partition,the reducible projection-system and correlation matrices, two characterizations for a rank three operator in a CSL algebra can be completely decomposed are given.     

HANKEL OPERATORS ON HARDY SPACES AND SCHATTEN CLASSES

For a holomorphic function f on the unit ball B~N of C~N, it is proved that the reduced Hankel oporator R_f on Hardy space H~2(B~N) is of Schatten class S_p for p≥1 if and only if f is in a corresponding Sobolev space.     

ON THE L~p-BOUNDEDNESS OF SEVERAL CLASSES OF PSEUDO-DIF FERENTIAL OPERATORS

To indicate precisely the requirements for smoothness of symbols,generalizations ofH(?)rmander's classes of symbols,S_(ρ,k(?),v)~m and S_(ρ,k(?),v(?))~m,are introduced.The main results areas follows:(1)An optimal L~2-boundedness result is obtained for the pseudo-differentialoperators with double symbols(amplitude)a(x,(?),y);(2)By means of the interpolationtheorem due to Fefferman and Stein,new L~p-boundedness results are established.Theseresults are not only sharp with respect to upper index,but also sharp(p≥2)or almost sharp(1相似文献   

非等谱Lax算子族的Virasoro代数

非等谱Ｌａｘ算子族的Ｖｉｒａｓｏｒｏ代数马文秀（复旦大学数学研究所，上海２００４３３）国家博士后科学基金资助项目．１９９１年７月２５日收到．１９９２年７月６日收到修改稿．一、引言Ｌａｘ算子方法［１］在可积系统理论中有着广泛的应用．从一个谱问题出发我们...     

HANKEL OPERATORS AND HANKEL ALGEBRAS

ＨＡＮＫＥＬＯＰＥＲＡＴＯＲＳＡＮＤＨＡＮＫＥＬＡＬＧＥＢＲＡＳＹＡＮＳＨＡＯＺＯＮＧＣＨＥＮＸＩＡＯＭＡＮＧＵＯＫＵＮＹＵＭａｎｕｓｃｒｉｐｔｒｅｃｅｉｖｅｄＪｕｎｅ２３，１９９５．ＩｎｓｔｉｔｕｔｅｏｆＭａｔｈｅｍａｔｉｃｓ，Ｆｕｄａ...     

ON K 2 OF DIVISION ALGEBRAS

ABSTRACT

In this paper, it is proved that if F is a global field, then for any integer n > 3, there is an extension field E over F of degree n such that K ₂ E is not generated by the Steinberg symbols {a, b} with a ∈ F*, b, ∈ E*. If however, F is a number field and D is a finite-dimensional central division F-algebra with square free index, then K ₂ D is always generated by the Steinberg symbols {a, b} with a ∈ F*, b ∈ D*. Finally, the tame kernels of central division algebras over F are expressed explicitly.     

关于两类特殊的代数

本文对泛代数中两类代作了一些研究，得到一些结果，并且讨论了这两类代数在半群中的应用。     

几种新寿命分布类

本文在前人研究的寿命分布类的基础上，给出了几种新的寿命分布类的定义，并研究了其有关的性质(主要是封闭性质)．     

算子变形的一种方法

本文提出算子的一种变形方法,可以改善算子的逼近度.§1叙述这种变形的方法,§2讨论它的某些应用.§1.算子变形的一种方法C~n[α,b]表示区间[α,b]上具有 n 阶连续导数的函数类,用 C[α,b]表示[α,b]上的连续函数全体.有线性算子     

关于单李代数的Coxeter-Killing变换

<正> 决定复单李群(代数)的Betti数是个经典的问题.大家知道,它们就是该李群(代数)的Poincare多项式     

关于从属族的支撑点

本文证明了当Ｆ∈Ｈｐ（１≤ｐ≤∞）且Ｆ′（０）≠０时等式。成立．从而证明了当Ｆ′（０）≠０时Ａｂｕ－Ｍｕｈａｎｎａ的猜想是成立的．除此之外，我们完全决定了一些从属族的支撑点且得到了上述等式成立的几个充分条件．推广了Ｄ．Ｊ．ＨａｌｌｅｎｂｅＣｋ，Ｔ．Ｈ．ＭａｃＧｒｅｇｏｒ的结果．     

A NOTE ON REDUCTIVITY OF OPERATORS

P. Rosenthal introduced the following property(P):If u is any reductive algebra and T∈u', then T~*∈u'.In this note, the author proves(1) A reductive spectral operator with polynomially compact quasinilpotent part has property(P);(2) A reductive spectral operator with algebraic quasinilpotent part has property(P);(3) The countable direct sum of scalar operators has property(P);(4) If T is reductive and T is quasi-similar to a polynomially compact operator, then T is normal.     

关于算子正矩阵

关于算子正矩阵侯晋川，高明杵（山西师范大学数学系，临汾０４１００４）基金项目：国家自然科学基金、山西省自然科学基金资助课题１９９２年３月１９日收到．由于应用的广泛性，人们对于寻求块方阵（）为半正定矩阵的（充分或必要）条件一直很感兴趣，且已获得许多深刻...