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1.
本文利用严格分离向量和严格分离泛函讨论了算子子空间的自反性及遗传自反性  相似文献   

2.
邸孝君 《数学杂志》1990,10(3):317-320
本文给出了(L_p)性质的定义,并就具有该性质的Banach空间进行了讨论,给出了这一性质的对偶性质,证明了若 X 与 X~* 均具(L_p)性性,则 X 是自反的。  相似文献   

3.
设A是B(X)的子代数,且A具有分离向量x0,本文讨论它的2-自反性和亚自反性,并就具有分离向量的交换算子代数.部分地回答了J.A.Deddens在文献[7]中提出的一些关于自反性的问题.  相似文献   

4.
韩志清 《应用数学》1997,10(1):10-12
本文给出了一个雄的分离定理并利用它给出了在Banach空间情形Benson真有效点的一个刻划.  相似文献   

5.
组合逻辑中的一个新的(ξ)规则   总被引:2,自引:0,他引:2  
宋方敏 《数学学报》1997,40(5):669-674
作者提出一个新的规则(ξ0),在组合逻辑的弱相等性理论CLw加入(ξ0)之后,弱相等性被加强为ξ0相等性.作者证明ξ0相等性严格强于弱相等性,但严格弱于组合β相等性,作者给出ξ0相等性的有穷公理化.  相似文献   

6.
廖贻华  程福长 《数学研究》2001,34(3):321-326
通过π-凝聚环上的f.g.模的自反性引进了WQF-环和GIF-环,给出了QF-环-个新的刻画,并研究了π-凝聚环上的W∧n模上的自反性的特征性质。  相似文献   

7.
本文利用单调型强制映射满射性和逼近方法建立了广义Hammerstein型方程u+K(u)F(u)=0解的存在性定理,这里对于实自反Banach空间X的共轭空间X*的每个u,K(u):X→X*是线性映射,F:X*→X是任一映射.所得结果推广了Schiling,Srikanth and Joshi等相应的结果  相似文献   

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设X是半自共轭的Banach空间,而A是B(X)的严格循环的交换子代数,考虑算子代数A的一些性质,这些性质与算子代数的自反性有关,而且这些性质为讨论A的自反性提供了理论基础.  相似文献   

9.
中X是自反Banach空间,K是X的有界、闭、凸子集。研究包含(M)型算子的变分不等式问题:A↑f∈X,求u∈K,使(w-f,v-u)≥0,w∈Tu。其中T是一个有限连续.(M)型、有界集值映射。利用KKM映射和Gwinner定理,我们得到了该变分不等式可解性的结果。最后讨论了这样的变分不等式它的应用。  相似文献   

10.
线性距离空间的一致凸性与自反性   总被引:2,自引:0,他引:2  
武俊德  曲文波 《应用数学》1995,8(3):322-324
本文研究了线性距离空间的一致凸性与自反性,同时对吴从Xin等提出的严格缩条件能否去掉的问题给出了肯定的答案。  相似文献   

11.
Let X and Y denote compact Hausdorff spaces and let K = R (real numbers) or C(complex numbers). C(X) and C(Y) denote the spaces of K-valued continuous functions on X and Y, respectively. A map H : C(X) C(Y) is separating if fg = 0 implies that HfHg = 0. Results about automatic continuity and the form of additive and linear separating maps have been developed in [1], [2], [3], [4], [5], [7], [8], and [10]. In this article similar results are developed for subadditive separating maps. We show (Theorem 5.11) that certain biseparating, subadditive bijections H are automatically continuous.  相似文献   

12.
In this paper, we study the Ramsey‐type weak K?nig's Lemma, written , using a technique introduced by Lerman, Solomon, and the second author. This technique uses iterated forcing to construct an ω‐model satisfying one principle T1 but not another T2. The technique often allows one to translate a “one step” construction (building an instance of T2 along with a collection of solutions to each computable instance of T1) into an ω‐model separation (building a computable instance of T2 together with a Turing ideal where T1 holds but this instance has no solution). We illustrate this translation by separating from (reproving a result of Ambos‐Spies, Kjos‐Hanssen, Lempp, and Slaman), and then apply this technique to separate from (which has been shown separately by Bienvenu, Patey, and Shafer).  相似文献   

13.
The set which forms the boundary of the regions of interferencewhen a family of curves is superposed on a parallel gratingis related to the envelopes of two ‘interference sets’in two fixed directions.  相似文献   

14.
With respect to a collection of N + m + 1 points in Em and an integer k, 0 ? k ? N; a criterion is given for the existence of a hypersphere through m specified points and one other, so that the remaining N points are separated into k interior and N ? k exterior. This result is used to solve some particular problems of separating points in the plane by circles.  相似文献   

15.
We investigate the problem of finding a set of prime divisorsof the order of a finite group, such that no two irreduciblecharacters are in the same p-block for all primes p in the set.Our main focus is on the simple and quasi-simple groups. Forresults on the alternating and symmetric groups and their doublecovers, some combinatorial results on the cores of partitionsare proved, which may be of independent interest. We also studythe problem for groups of Lie type. The sporadic groups (andtheir relatives) are checked using GAP.  相似文献   

16.
It is an open problem whether every one-dimensional extension of a triangular operator admits a separating vector. We prove that the answer is positive for many triangular Hilbert space operators, and in particular, for strictly triangular operators. This is revealing, because two-dimensional extensions of such operators can fail to have separating vectors.

  相似文献   


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The classical Beardwood‐Halton‐Hammersly theorem (1959) asserts the existence of an asymptotic formula of the form for the minimum length of a Traveling Salesperson Tour throuh n random points in the unit square, and in the decades since it was proved, the existence of such formulas has been shown for other such Euclidean functionals on random points in the unit square as well. Despite more than 50 years of attention, however, it remained unknown whether the minimum length TSP through n random points in was asymptotically distinct from its natural lower bounds, such as the minimum length spanning tree, the minimum length 2‐factor, or, as raised by Goemans and Bertsimas, from its linear programming relaxation. We prove that the TSP on random points in Euclidean space is indeed asymptotically distinct from these and other natural lower bounds, and show that this separation implies that branch‐and‐bound algorithms based on these natural lower bounds must take nearly exponential () time to solve the TSP to optimality, even in average case. This is the first average‐case superpolynomial lower bound for these branch‐and‐bound algorithms (a lower bound as strong as was not even been known in worst‐case analysis). © 2016 Wiley Periodicals, Inc. Random Struct. Alg., 51, 375–403, 2017  相似文献   

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