共查询到20条相似文献,搜索用时 46 毫秒
1.
设N是Hilbert空间H上的一个完备套,是N上的标准谱测度.本文给出了H上任一有界线性算子T到套代数Alg N的Larson理想RN的距离公式为AlgN的半根理想,则d(T,RN)=sup{iN(T):N}. 相似文献
2.
《Journal of Computational and Applied Mathematics》2002,142(2):377-388
The combined random number (RN) generator has been considered by many scholars as a good RN generator. One promising type of combined RN generator, recommended by L'Ecuyer (Oper. Res. 44 (1996) 816; 47 (1999) 159), is the combined multiple recursive generator (MRG). This paper analyzes the combined MRG via the Chinese remainder theorem. A new combined generator based on the generalized Chinese remainder theorem and on the Ore algorithm (Amer. Math. Monthly 59 (1952) 365) is presented. The proposed combined generator improves the combined MRG in terms of both the suitability for various types of RN generators and the restriction on the moduli of the individual generators. Therefore, the proposed combined generator is an ideal RN generator and is most recommended. 相似文献
3.
4.
本文讨论了如下一类非线性薛定谔方程:-△u+V(x)u=f(u),x∈R^N,在H^1(R^N)中无穷多解的存在性,其中N≥3,V(x)是RN上的实值连续函数并且满足对(A)x∈R^N,V(z)≥V0>0. 相似文献
5.
DONG Zhe 《数学年刊B辑(英文版)》2003,24(3):323-330
This paper studies the tensor product RN RM of Jacobson radicals in nest algebras, and obtains that RN RM = {T∈B(H1 H2) : T(N M)(?)N_ M_, N∈N,M∈M}; and based on the characterization of rank-one operators in RN RM,it is proved that if N, M are non-trivial then RN RM=R if and only if N, M are continuous. 相似文献
6.
Following the definition of S. Gudder and J. Zerbe, we say that a logicL has the Radon-Nikodym property (or, in short,L is an RN logic) if the following condition holds: Ifs, t are states onL ands is absolutely continuous with respect tot, then there is a central observablex such that
for allaL. We first consider general RN logics. We establish their basic properties and show that they are closed under the formation of epimorphisms and products. Then we take up the RN property for concrete logics. We first show that in many cases the concrete RN logics have to be fully compatible (= Boolean -algebras). In contrast to that, we show that there are concrete RN logics with an arbitrary degree of noncompatibility. This extends the result of Navara and Pták and answers in full the question posed by Gudder and Zerbe. 相似文献
7.
Let XH = {XH(s),s ∈RN1} and X K = {XK(t),t ∈R N2} be two independent anisotropic Gaussian random fields with values in R d with indices H =(H1,...,HN1) ∈(0,1)N1,K =(K1,...,KN2) ∈(0,1) N2,respectively.Existence of intersections of the sample paths of X H and X K is studied.More generally,let E1■RN1,E2■RN2 and FRd be Borel sets.A necessary condition and a sufficient condition for P{(XH(E1)∩XK(E2))∩F≠Ф}>0 in terms of the Bessel-Riesz type capacity and Hausdorff measure of E1×E2×F in the metric space(RN1+N2+d,) are proved,where is a metric defined in terms of H and K.These results are applicable to solutions of stochastic heat equations driven by space-time Gaussian noise and fractional Brownian sheets. 相似文献
8.
Robert Molina 《Journal of Graph Theory》1995,19(3):375-384
The edge reconstruction number of a graph G, RN(G), is the minimum number of edge deleted subgraphs required to determine G up to isomorphism. We prove the following results for a disconnected graph G with at least two nontrivial components. If G has a pair of nontrivial nonisomorphic components then RN(G) ≤ 3. If G has a pair of nontrivial nonisomorphic components, is not a forest, and contains a nontrivial component other than K3 or K1,3 then RN(G) ≤ 2. Finally, if all nontrivial components of G are isomorphic to a graph with k edges, then RN(G) ≤ k + 2. The edge reconstruction results in this paper are similar to the vertex reconstruction results stated by Myrvold (“The Ally-Reconstruction Number of a Disconnected Graph,” Ars Combinatoria, Vol. 28 [1989] pp. 123-127), but a significant difference is that the edge reconstruction number of a disconnected graph is often two, while the vertex reconstruction number of a graph is always three or more. © 1995 John Wiley & Sons, Inc. 相似文献
9.
给出了紧致taut子流形的一个性质,即它确实是由标准球面堆砌(buildup)而成的.本文也证明了某类近复子流形可taut嵌入到RN. 相似文献
10.
本文揭示了一个事实,小波不仅可构成L2空间中的正交基,小波分解与重构滤波还可产生N维空间中的正交基.在本文提出修改的小波变换算法之下,N点信号的小波变换等价于N维空间中的正交变换.用该算法进行信号或图象压缩,无需对信号或图象进行周期延拓,可严格地在N维空间中进行. 相似文献
11.
LOU Zengjian & Alan MclntoshInstitute of Mathematics Shantou University Shantou China 《中国科学A辑(英文版)》2004,47(2)
We introduce a divergence-free Hardy space Hz1,div(RN+,RN) and prove its divergence-free atomic decomposition. We also characterize its dual space and establish a "div-curl" type theorem on R+3 with an application to coercivity properties of some polyconvex quadratic forms. 相似文献
12.
LetG be a classical algebraic group defined over an algebraically closed field. We classify all instances when a parabolic subgroupP ofG acts on its unipotent radicalP
u
, or onp
u
, the Lie algebra ofP
u
, with only a finite number of orbits.The proof proceeds in two parts. First we obtain a reduction to the case of general linear groups. In a second step, a solution for these is achieved by studying the representation theory of a particular quiver with certain relations.Furthermore, for general linear groups we obtain a combinatorial formula for the number of orbits in the finite cases. 相似文献
13.
It is shown that the Behrens radical of a polynomial ring, in either commuting or non-commuting indeterminates, has the form of “polynomials over an ideal”. Moreover, in the case of non-commuting indeterminates, for a given coefficient ring, the ideal does not depend on the cardinality of the set of indeterminates. However, in contrast to the Brown-McCoy radical, it can happen that the polynomial ring R[X] in an infinite set X of commuting indeterminates over a ring R is Behrens radical while the polynomial ring R〈X〉 in an infinite set Y of non-commuting indeterminates over R is not Behrens radical. This is connected with the fact that the matrix rings over Behrens radical rings need not be Behrens radical. The class of Behrens radical rings, which is closed under taking matrix rings, is described. 相似文献
14.
This paper studies the following semilinear SchrSdinger problem -Δu v(x)u=λu-g(x)|u|^p-1u,x∈R^N It is proven that there exists a bifurcation branch of solutions for the above problem, when g(x) can possibly vanish except for a bounded domain Ω∈R^N. 相似文献
15.
Let xm ? a be irreducible over F with char and let α be a root of xm ? a. The purpose of this paper is to study the lattice of subfields of and to this end is defined to be the number of subfields of F(α) of degree k over is explicitly determined for p a prime and the following structure theorem for the lattice of subfields is proved. Let N be the maximal normal subfield of F(α) over F and set n = |N : F|, then . The irreducible binomials xs ? b, xs ? c are said to be equivalent if there exist roots βs = b, γs = a such that F(β) = F(γ). All the mutually inequivalent binomials which have roots in F(α) are determined. Finally these results are applied to the study of normal binomials and those irreducible binomials x2e ? a which are normal over F (char F ≠ 2) together with their Galois groups are characterized. 相似文献
16.
For an arbitrary group?G and a G-graded Lie algebra L over a field of characteristic zero we show that the Kostrikin radical of?L is graded and coincides with the graded Kostrikin radical of?L. As an important tool for our proof we show that the graded Kostrikin radical is the intersection of all graded-strongly prime ideals of?L. In particular, graded-nondegenerate Lie algebras are subdirect products of graded-strongly prime Lie algebras. 相似文献
17.
We prove that any projective Schur algebra over a field K isequivalent in Br(K) to a radical abelian algebra. This was conjecturedin 1995 by Sonn and the first author of this paper. As a consequence,we obtain a characterization of the projective Schur group bymeans of Galois cohomology. The conjecture was known for algebrasover fields of positive characteristic. In characteristic zerothe conjecture was known for algebras over fields with a Henselianvaluation over a local or global field of characteristic zero. 相似文献
18.
19.
Morris Newman 《Journal of Number Theory》1981,13(4):495-498
All solutions in positive integers x, yz of the diophantine equation are determined, where m, n, r are given positive integers. The proof makes use of a simple criterion for the irreducibility of the polynomial xn ? a over the rationals, where a is a positive rational. 相似文献
20.
给出增线性椭圆方程-△u=λV(x)u+f(x.u)在Ω上的一个非零解,其中Ω
RN(N≥3)可以无界.并允许Ω=RN.V(x)可以变号,并通过截断技巧得到上述问题的一个非负解和一个非正解. 相似文献