HILBERT TRANSFORHS FOR CONVEX CURVES IN R~n

Let г:[-1,1]→R~n be a curve in R~n,n≧2,with г(0)=0.To г we associate the Hilbert transform operator H defined bythe principal value integralHf(x)=P.V.f(x-г(t))(dt)/t(x∈R~n),(1)where f is an arbitrary function in an appropriate class.A pro-     

幂群与它的生成群

设г是G上的幂群,即以G的非空子集为元素,在G的子集的运算之下所成的群.P_1,P_2是这样的两个性质 P_1:对任意g∈G,存g∈G,存在A∈г,使得g∈A. P_2:对任意A,B∈г,如果A≠B,则A∩B=φ. 本文得出了群G上的幂群г分别具有性质P_1或P_2的充要条件.     

von Neumann代数中的*-偏序

设H是复Hilbert空间,B(H)是H上的有界线性算子全体组成的代数,M?B(H)是von Neumann代数,"≤"表示M中的*-偏序,即A,B∈M,若A~*A=A~*B,AA~*=BA~*,则A≤B.本文研究了von Neumann代数中*-偏序的上确界和下确界,证明了von Neumann代数M的子集关于*-偏序的上、下确界和B(H)中的上、下确界一致.同时,给出了M的*-偏序遗传子空间的表示,证明了弱~*闭子空间A?M,满足A∈M,B∈A,由A≤B可得A∈A,当且仅当存在唯一具有相同中心投影的投影对E,F∈M,使得A=EMF.     

杨乐不等式的两个初等证明

这里给出杨乐不等式则与目前已见到的证明不同的两个初等证明．证明1（三角变换法）汪意到余弦函数在[0，π]上是减函数，有又由A＞0，B＞0，A＋B≤π知|A－B|＜π，从而有COSμ（A-B）=COSμ|A-B|＞COSμπ由①②③即知（*）成立．证明2（构造模型法）当μ=1时易知（*）成立；当0＜μ≤时，构造△A1B1C1，真外接圆直径2R＝1．因在一个三角形中至少有两个内角为锐角，不妨设A1与B1都是锐角，并且令在△A1B1C1中用正弦定理，有A1B1＝sinμ（A＋B）再用宗弦定理，有比较（*）与（**）可以看出：欲证（*）成立，只需证就可以了．…     

具有d-Koszul子模滤的分次模

引入了弱d-Koszul模,它是d-Koszul模的一种自然推广.设A是d-Koszul代数,M是有限生成的分次A-模,则M是弱d-Koszul模当且仅当M具有子模滤 0(∪) U0(∪)U1(∪)…(∪)Up=M,使得所有的A-模 Ui/Ui-1是d-Koszul模.设M为一个弱d-Koszul模,则作为分次Ext*A(A0,A0)-模,其Koszul对偶,ε(M)=Ext*A(M,A0)是由0次生成的.     

由常微分线性算子确定的某一光滑函数类在L-2空间的n-K宽度

设M（u)是给定的N函数,A=D^r ∑r-1k=0ak(x)D^k是r阶线性微分算子,WM（A）是由M（u)和A所确定的Sobolev-Orlicz类,本文给出n-K宽度dn(WM(A),L2[0,1])的渐近估计。     

素＊-环上非线性保XY-ξYX~＊积

设M是包含非平凡投影P的单位素*-环.证明了非线性双射φ:M→M对所有A,B∈M,满足φ(AB-ξBA*)=φ(A)φ(B)—ξφ(B)φ(A)*.若ξ=1,则φ是线性或共轭线性的*-同构;若ξ≠1,则φ是*-环同构,且对所有A∈M,有φ(ξA)=ξφ(A).     

A Characterization of a Class of Symmetric Graphs of Twice Prime Valency

Let г be a connected undirected graph aud G a group of automorphisms ofг.G is said to act symmetrically on г and г is said to be G-symmetric, if G istransitive on the set {(α,β) |α,β adjacent vertices} of 1-arcs of г. Thus G is tran-sitive on vertices and the stablizer G_a of a vertex a is transitive on the set г_1(a)     

因子冯诺依曼代数上的第二类非线性混合Lie三重导子（英文）

设M是一个维数大于1的因子冯诺依曼代数,且L:M→M是一个第二类非线性混合Lie三重导子,即对任意的A,B,C∈M满足L([[A,B],C]_*)=[[L(A),B],C]_*+[[A,L(B)],C]_*+[[A,B],L(C)]_*.则L是一个可加的*-导子.     

量子群的基变换与范畴同构

令Ｍ是Ｚ［ｖ］的由ｖ－１和奇素数ｐ生成的理想，Ｕ是Ａ＝Ｚ［ｖ］Ｍ上相伴于对称Ｃａｒｔａｎ矩阵的量子群， Ａ－Γ是环同态， Ｕг＝ＵＡΓ［Ｕг］是Ｕг的量子坐标代数，本文建立了量子坐标代数的基变换：即在相关约束条件下有Г－Ｈｏｐｆ同构 Ａ［Ｕ］ＡГ≌Г［Ｕг］．我们证明了有限秩 Ａ自由 １型可积 Ｕ模范畴和有限秩 Ａ自由 Ａ［Ｕ］余模范畴是同构的．特别，当 Г是域时，局部有限 １型 Ｕг模范畴和Г［Ｕг］余模范畴是同构的．最后，我们还证明了在［１］中定义的诱导函子和Ｂ．Ｐａｒｓｈａｌｌ与王建磐博士在［２］中研究的诱导函子的一致性．     

Eigenvectors and cyclic vectors of bilateral weighted shifts. II: Simply invariant subspaces

Let T be an injective bilateral weighted shift onl ² thought as "multiplication by λ" on a space of formal Laurent series L²(β). (a) If L²(β) is contained in a space of quasi-analytic class of functions, then the point spectrum σ_p(T^?) of T^? contains a circle and the cyclic invariant subspaceM _f of T generated by f is simply invariant (i.e., ∩{(T^k M _f)^?: k ≥ 0}= {0}) for each f in L²(β); (b) If L²(β) contains a non-quasi-analytic class of functions (defined on a circle г) of a certain type related with the weight sequence of T, then there exists f in L²(ß) such thatM _f is a non-trivial doubly invariant subspace (i.e., (TM _f)^? =M _f); furthermore, if г ? σ_p(T^*), then σ_p (T^*) = г and f can be chosen so that σ_p([T∣M _f]^*) = г?{α}, for some α ε г. Several examples show that the gap between operators satisfying (a) and operators satisfying (b) is rather small.     

算子代数上的Jordan初等映射(英文)

给定两个环R,R’.对于满足一定条件的环R,本文证明了若M:R→R’,M*:R’→R为满射且对A,C∈R和B,D∈R’满足M（AM*（B）C+CM*（B）A）=M（A）BM（C）+M（C）BM（A）,M*（BM（A）D+DM（A）B）=M*（B）AM*（D）+M*（D）AM*（B）则M和M*是可加的;若R和R’分别包含单位I和I’,M（I）,M*（I’）可逆,则存在环同构N使得M（A）=N（A）M（I）,M*（B）=N^-1（BM（I））.特别地,若R=R’为标准算子代数或Hilbert空间套代数,则M和M*可加且存在有界可逆的线性或共轭线性算子S和T使得M（A）=SAT,M*（B）=TBS或M（A）=TA*S,M*（B）=（SBT）*对任意的A,B∈R成立.     

Analytic discs under sympletic transforms

By a holomorphic homogeneous symplectic transformation of T*X (for X = ?^N), we interchange the conormal bundle T _M ^* X to a higher codimensional submanifold M with the conormal bundle T _M ^* X to a hypersurface M of X. For an analytic disc A “attached” to M we are able to find a section A* ?T*X with π A* = A, attached to T _M ^* X, such that Ã:= πx(A*) is an analytic disc “attached” to M. By this procedure of “transferring” analytic discs, we get the higher codimensional version of our criteria of [5] on holomorphic extension of CR functions (with [5] being on its hand the main tool of the present proof). Thus, let W be a wedge of X with generic edge M and assume that there exists an analytic disc contained in M ∪ W, tangent to M at a boundary point z₀∈ ?A, and not contained in M in any neighborhood of z₀. Then germs of holomorphic functions on W at z₀ extend to a full neighborhood of z₀.     

关于强拓扑对偶多重Hilbert空间上连续线性算子的（C_0，1）－发展系

本文证明：若强对偶多重Ｈｉｌｂｅｒｔ空间上的（Ｃ＿０，１）－半群族的无穷小生成算子族是г－稳定的，则该半群族生成г－稳定的发展系．基于此，本文还得出了关于（Ｃ＿０，１）－发展系的一个摄动定理．     

Correction to: ‘The UCT, the Milnor Sequence, and a Canonical Decomposition of the Kasparov Groups’

In this note we correct a mistake in K-Theory 10 (1996), 49–72. In that paper we asserted that under bootstrap hypotheses the short exact sequence

*-Identities of Minimal Degree in Matrix Algebras of Low Order

Let M6(K,*) be the 6 × 6 matrix algebra with symplectic involution over a field K of characteristic 0. We consider *-polynomial identities in symmetric to the involution matrices and prove that their minimal degree in M6(K,*) is 9. For special *-polynomials we make the conjecture that their minimal degree in M2n(K,*) for n 2 is 4n.     

On the Finite Model Property of Intuitionistic Modal Logics over MIPC

MIPC is a well-known intuitionistic modal logic of Prior (1957) and Bull (1966). It is shown that every normal intuitionistic modal logic L over MIPC has the finite model property whenever L is Kripke-complete and universal.