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1.
陈吉象 《数学学报》1998,41(3):471-474
K.A.Hardie与K.H.Kamps研究过固定空间B上的迹同伦范畴([1]).他们引进了两对伴随函子PB┤NB与m┤m,此处m:AB是固定映射,PB:HBHB与m:HAHB是函子.我们在[2]中引进了分裂的范畴纤维化L:HbHB,并且证明了L┤J,J┤L.本文首先将PB┤NB推广到PBb┤NBb#,其中b:BB是任一固定映射,并且我们还得到涉及迹同伦范畴Hb与Hb的两对伴随函子,此处Hb是Hb的对偶.特别,Nb┤Pb不同于PB┤NB.  相似文献   

2.
Let H and K be indefinite inner product spaces. This paper shows that a bijective map φ:B(H)→B(K) satisfies φ(AB B A) =φ(A)φ(5) φ(B) φ(A) for every pair A,B ∈B(H) if and only if either φ(A) = cU AU for all A or φ(A) = cUA U for all A; φsatisfies φ(AB A) = φ(A)φ(B) φ(A) for every pair A,B ∈B(H) if and only if either φ(A) = UAV for all A or φ(A) = UA V for all A, where A denotes the indefinite conjugate of A, U and V are bounded invertible linear or conjugate linear operators with U U = c-1I and V V = cI for some nonzero real number c.  相似文献   

3.
Let B be a domain ?? that supports nonconstant bounded analytic functions, let pe B. In [1] S.Fisher posed the question: Does the Ahlforsfunction for B and p map a maximal B onto the unit disc D? We give an example of a maximal B such that in B F(z) omits two values of D.  相似文献   

4.
赵文正 《数学学报》2000,43(4):677-684
本文给出了DoiY.构造的偶交叉积BT■H的代数结构与ReshetikhimN.构造的双代数B■RH的余代数结构在张量空间B■H上构成双代数(记为Bτ■RH)的充要条件,利用此结论具体构造了一个有趣的例子B4■KZ2;证明了当B,H均为Hopf.代数时Bτ■RH也为Hopf代数,最后给出这类双代数的映射刻划。  相似文献   

5.
One investigates estimates of the type ∥ABx∥?f(B)∥Ax∥, where A, B are matrices and x is a vector belonging to a certain subspace. One investigates the properties of the matrix seminorm f(B), in particular, its relation to the spectrum of the matrix B. For the case of a stochastic matrix B (which can be easily generalized to the case of a nonnegative matrix B) one derives estimates for f(B) which are convenient for practical computations (also on an electronic computer). One gives a numerical example illustrating the application of the results.  相似文献   

6.
本文给出了Doi Y.构造的偶交叉积B H的代数结构与Reshetikhim~N.构造的双代数BRH的余代数结构在张量空间B H上构成双代数(记为BRH)的充要条件,利用此结论具体构造了一个有趣的例子H4 KZ2,证明了当B,H均为Hopf.代数时BRH也为Hopf代数,最后给出这类双代数的映射刻划.  相似文献   

7.
Let H be an infinite dimensional complex Hilbert space. Denote by B(H)the algebra of all bounded linear operators on H, and by I(H) the set of all idempotents in B(H). Suppose that φ is a surjective map from B(H) onto itself. If for everyλ∈ {-1, 1, 2, 3, 1/2, 1/3} and A, B ∈ B(H), A - λB ∈ I(H) (→)φ(A) - λφ(B) ∈ I(H), then φis a Jordan ring automorphism, i.e. there exists a continuous invertible linear or conjugate linear operator T on H such that φ(A) = TAT-1 for all A ∈ B(H), or φ(A) = TA*T-1 for all A ∈ B(H); if, in addition, A - iB ∈ I(H) (→)φ(A) - iφ(B) ∈ I(H), here i is the imaginary unit, then φ is either an automorphism or an anti-automorphism.  相似文献   

8.
The formula dim(A+B)=dim(A)+dim(B)-dim(A∩B) works when ‘dim’ stands for the dimension of subspaces A,B of any vector space. In general, however, it does no longer hold if 'dim' means the uniform (or Goldie) dimension of submodules A,B of a module M over a ring R, and in fact the left hand side may be infinite while the right hand side is finite. In this paper we shall give a characterization of those modules M in which the formula holds for any two submodules A,B, as well as some conditions in the ring R which guarantee that dim(A+B) is finite whenever A and B are finite dimensional R-modules.  相似文献   

9.
Let H(B) be the set of all harmonic functions f on the unit ball B of Rn. For 0 < p, q ≤∞ and a normal weight φ, the mixed norm space Hp,q, φ(B) consists of all functions f in H(B) for which the mixed norm p,q, φ < ∞. In this article, we obtain some characterizations in terms of radial, tangential, and partial derivative norms in Hp,q, φ(B). The parallel results for the Bloch-type space are also obtained. As an application, the analogous problems for polyharmonic functions are discussed.  相似文献   

10.

In this paper, we study the variation of invariant Green potentials G w in the unit ball B of $ {\shadC}^n$ , which for suitable measures w are defined by $$ G_{\mu}(z) = \int_{B}G(z,w)\, d\mu(w), $$ where G is the invariant Green function for the Laplace-Beltrami operator ¨ j on B . The main result of the paper is as follows. Let w be a non-negative regular Borel measure on B satisfying $$ \int_{B}(1-|w|^2)^n\log {1 \over (1-|w|^2)}\, \d\mu(w) ] B , { z denotes the holomorphic automorphism of B satisfying { z (0) = z , { z ( z ) = 0 and ( { z { z )( w ) = w for every w ] B .  相似文献   

11.
Optimal numerical approximation of bounded linear functionals by weighted sums in Hilbert spaces of functions defined in a domain B ? C or B ? Rm, invariant in rotation or translation (e.g. circle, circular annulus, ball, spherical shell, strip of the complex plane) and equipped with inner product invariant in rotation or translation are considered. The weights and error functional norms for optimal approximate rules based on nodes located angle-equidistant on concentric spheres or circles of B, for B invariant in rotation, and on nodes located equispaced on in B lying line, for B invariant in translation, are explicitly given in terms of the kernel function of the Hilbert space. A number of concrete Hilbert spaces satisfying the required conditions are listed.  相似文献   

12.
By using the theory of the cone and partial ordering. It is studied that the existence and uniqueness of solutions for a non-monotone binary operator equation A(x, x)= x and operator system of equations A(x,x)=x,B(x,x)=x in Banach spaces. Where A and B can be decomposed A=A1+A2, B=B1+B2,A1 and B1 are mixed monotone, A2 and B2 are anti-mixed monotone. The results presented here improve and generalize some corresponding results of mixed monotone operator equations.  相似文献   

13.
设X是维数大于2的Banach空间,映射δ:B(X)→B(X)是2-局部Lie三重导子,则对所有A∈B(X)有δ(A)=[A,T]+ψ(A),这里T∈B(X),ψ是从B(X)到FI的齐次映射且满足对所有A,B∈B(X)有ψ(A+B)=ψ(A),其中B是交换子的和.  相似文献   

14.
In the current paper, we examine the effect of a B2B spot market on the strategic behavior and the performance of a reseller who continues to use the traditional channel while participating in a B2B spot market. We analyze the case in which a risk-neutral reseller faces an additive or multiplicative demand function and identify sufficient conditions under which the optimal order quantity and retail price exist and are unique. We then analytically examine the case in which a risk-averse reseller participates in a fully liquid spot market. We also study numerically how varying liquidity, spot price volatility, demand variability, and correlation coefficient affect a firm’s strategies and performance. We find that demand variability significantly affects both pricing and ordering strategies, whereas the spot price volatility has less influence on pricing decisions. Our results also show that for a risk-averse reseller to charge a lower retail price when the spot market liquidity increases is desirable. We further show that a B2B spot market cannot always improve a reseller’s utility. These findings shed light on how resellers can adjust their procurement and pricing strategies to align with the new business environment created by the emergence of B2B spot markets, as well as have obvious implications for the development of a B2B spot market.  相似文献   

15.
In the last twenty years, a theory of real Jordan triples has been developed. In 1994 T. Dang and B. Russo introduced the concept of J*B–triple. These J*B–triples include real C*–algebras and complex JB*–triples. However, concerning J*B–triples, an important problem was left open. Indeed, the question was whether the complexification of a J*B–triple is a complex JB*–triple in some norm extending the original norm. T. Dang and B. Russo solved this problem for commutative J*B–triples. In this paper we characterize those J*B–triples with a unitary element whose complexifications are complex JB*–triples in some norm extending the original one. We actually find a necessary and sufficient new axiom to characterize those J*B–triples with a unitary element which are J*B–algebras in the sense of [1] or real JB*–triples in the sense of [4].  相似文献   

16.
We call T ∈ B(H) consistent in Fredholm and index (briefly a CFI operator) if for each B ∈ B(H),T B and BT are Fredholm together and the same index of B,or not Fredholm together.Using a new spectrum defined in view of the CFI operator,we give the equivalence of Weyl’s theorem and property (ω) for T and its conjugate operator T* .In addition,the property (ω) for operator matrices is considered.  相似文献   

17.
Y.Q. Chen  K.P. Shum 《代数通讯》2013,41(9):3043-3055
Let A, B be rings and P a radical property. Call B an A-Algebra if B is an A-bimodule such that (ba)b1 = b(ab1), (bb1)a = b(b1a), a(bb1) = (ab)b1 for any a ∈ A and any b,b1 ∈ B. A ring R, written as R = A ? B, is called a quasi-direct sum of (A, B) if A is a subring of R, B is an ideal of R and R is a direct sum of A and B as additive groups. The following results are obtained: 1. A quasi-direct sum of (A, B) is uniquely determined by an A-Algebra B (up to isomorphism); 2. The P-radical of the Algebra B is the same as the P-radical of the ring B; 3. P(A ? B) = P(A) +(B) if and only if P(A)B + BP(A) ? P(B); 4. If B has an identity e then P(A ? B) = P(A)(1?e) + P(B); 5. If P(Z) = 0 for the integer ring Z, then P(Mn(R)) = Mn(P(R)) holds for all rings R if and only if the above equality holds for all unitary rings R. In addition, some relationships of radicals between rings (or algebras over a field, semigroup algebras, etc.) and their corresponding identity extensions are discussed.  相似文献   

18.
Given a continuous seminorm p on a Hausdorff locally convex space X and nonempty subsets A, B of X, let Proximal(B;A) (resp. Prox(A,B)) denote the set of p-proximal points of B in A (resp. the set of ordered pairs of p-proximal points of the pair (A,B)). In this article we identify suitable families A,B of nonempty subsets of X and natural topologies on them with a view to study continuity properties of B →Proximal( B;A) and (A,B) →Prox(A,B). This leads us to obtain a best approximation result and a coincidence theorem for multifunctions defined on non-compact sets.  相似文献   

19.
初基演算     
沈有鼎 《数学学报》1957,7(1):132-143
<正> 命题演算的构成,通常有三步骤的说法,即从 Johanson 的“极小演算”到 Heyting的构造论命题演算再到二值演算.此外,Lewis 从模态或严格蕴涵出发,也分别了许多步骤,以达到二值演算为其极限;特别值得注意的是最后三个步骤,即从 S4 到 S5 到二值演算.这两个三步骤就某意义说乃是通常命题演算的构成中最本质的步骤.综合这两个三步骤,会带来许多便利,而本文所提出的也就是作为二者共同基础的初基演算.  相似文献   

20.
设B,H是两个Hopf代数,构造了(ω,σ)-Smash积Bω#σH和(ν,α)-Smash余积Bν■αH,并给出了Bω#σH是Hopf代数和Bν■αH是双代数的充要条件,证明了许多已知的积和余积是它们的特殊情况.  相似文献   

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