首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Let A be a topological space which is not finitely generated and CH(A) denote the coreflective hull of A in Top. We construct a generator of the coreflective subcategory SCH(A) consisting of all subspaces of spaces from CH(A) which is a prime space and has the same cardinality as A. We also show that if A and B are coreflective subcategories of Top such that the hereditary coreflective kernel of each of them is the subcategory FG of all finitely generated spaces, then the hereditary coreflective kernel of their join CH(AB) is again FG.  相似文献   

2.
In this paper, the concept of generalized semiregular rings is extended to generalized weak semiregular rings. Some properties of these rings are studied and some results about semiregular rings and generalized semiregular rings are extended. We also give some equivalent characterizations ofI-weak semiregular rings.  相似文献   

3.
具有相同广义反射函数的微分系统的等价性   总被引:1,自引:0,他引:1  
利用广义反射函数给出了微分系统等价的定义,研究了线性微分系统的相互等价性及其与非线性微分系统的等价性.  相似文献   

4.
Periodic binary (plus-minus) sequences all but one of whose out-of-phase autocorrelation coefficients are zero are studied by Wolfman [6]. Using the equivalence of these almost perfect sequences to certain cyclic divisible difference sets (noted by Bradley and Pott [1]), we settle the existence status of a perviously open case of an almost perfect sequence of length 852, thereby answering a question of Pott [5] negatively.  相似文献   

5.
Suppose f is an almost starlike function of order α on the unit disk D. In this paper, we will prove that Φn, β2, γ2, …, βn, γn (f)(z) = (f(z1), (f(z1)/z1)β2(f'(z1))γ2z2,…,(f(z1)/z1)βn(f'(z11))γnzn)' preserves almost starlikeness of order α on Ωn,p1,p2,…,pn = {z =(z1,z2,…,zn)' ∈ Cn n∑j=1 |zj|pj < 1}, where 0 < p11 ≤ 2, pj ≥ 1, j = 2,…,n, are real numbers.  相似文献   

6.
We establish extensions of the Crofton formula and, under some restrictions, of the principal kinematic formula of integral geometry from curvature measures to generalized curvature measures of convex bodies. We also treat versions for finite unions of convex bodies. As a consequence, we get a new intuitive interpretation of the area measures of Aleksandrov and Fenchel–Jessen.  相似文献   

7.
Roth定理在任意体上的推广   总被引:4,自引:1,他引:4  
本文给出了任意体上的矩阵方程AX—YB=C相容的两个充要条件,并给出了其一般解的表达式,从而推广了域上的W.E.Roth定理.  相似文献   

8.
Combinatorial objects called rigged configurations give rise to q-analogues of certain Littlewood–Richardson coefficients. The Kostka–Foulkes polynomials and two-column Macdonald–Kostka polynomials occur as special cases. Conjecturally these polynomials coincide with the Poincaré polynomials of isotypic components of certain graded GL(n)-modules supported in a nilpotent conjugacy class closure in gl(n).  相似文献   

9.
对称矩阵与反对称矩阵广义特征值反问题的拓广   总被引:1,自引:0,他引:1  
臧正松 《数学研究》2006,39(1):61-67
定义了上三角等次对角线矩阵和上三角交错次对角线矩阵;讨论了矩阵方程AX-XA=0的对称解与AX XA=0的反对称解.在此基础上考虑了以下问题的可解性:给定A∈Rn×m,D∈Rm×m,分别求X,Y∈SRn×n和X,Y∈ASRn×n,使得XA=YDA.  相似文献   

10.
The Hamilton–Waterloo problem asks for which s and r the complete graph can be decomposed into s copies of a given 2‐factor F1 and r copies of a given 2‐factor F2 (and one copy of a 1‐factor if n is even). In this paper, we generalize the problem to complete equipartite graphs and show that can be decomposed into s copies of a 2‐factor consisting of cycles of length xzm; and r copies of a 2‐factor consisting of cycles of length yzm, whenever m is odd, , , and . We also give some more general constructions where the cycles in a given two factor may have different lengths. We use these constructions to find solutions to the Hamilton–Waterloo problem for complete graphs.  相似文献   

11.
Generalized complex geometry is a new kind of geometrical structure which contains complex and symplectic geometry as its special cases. This paper gives the equivalence between the integrable conditions of a generalized almost complex structure in big bracket formalism and those in the general framework.  相似文献   

12.
安洪庆  陈永  孔雨佳 《大学数学》2008,24(1):129-134
主要利用同调的方法,对2-有限表现模作了细致的讨论.进而更加深入的刻画了G-平坦模的性质,并用G-平坦模更加具体得刻画了其他的一些代数结构,从而推广了[1,2]等文章中的结果.  相似文献   

13.
We report some results on the theory of quasiperiodic sphere packings controlled by a finite group G in the n-dimensional Euclidean space, constructed by means of an higher dimensional Euclidean space which contains G-invariant lattices. A generalization of the Hermite constant is used to find upper bounds of the density.  相似文献   

14.
研究了数理方程中一类典型的双曲型方程混合问题的古典解的拓广──广义解。  相似文献   

15.
计数数据往往存在过离散(over-dispersed)即方差大于均值特征,若利用传统的泊松回归模型拟合数据往往会导致其参数的标准误差被低估,显著性水平被高估的错误结论。负二项回归模型、广义泊松回归模型通常被用来处理过离散特征数据。本文以两类广义泊松回归模型GP-1和GP-2模型为基础,将其推广为更为一般的GP-P形式,其中P为参数。此时,P=1或P=2,GP-P模型就退化为GP-1和GP-2模型。文中最后利用此类推广的GP-P模型处理了一组医疗保险数据,并与泊松回归模型、负二项回归模型拟合结果进行了比较。结果表明,推广后的GP-P模型的拟合效果更优。  相似文献   

16.
Stability analysis of the upright position of a ship in random head or following seas is presented. Such seas lead to parametric excitation of roll motion due to periodic variations of the righting lever. The development of simple criteria for the occurrence of parametric induced roll motion in random seas is of major interest for improvement of the international code on intact stability provided by the International Maritime Organization. The stability analysis in random seas is based on the calculation of the top Lyapunov exponent using the fact, that a negative top Lyapunov exponent yields no roll motion. With this findings, roll motion can be excluded for specific sea states. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

17.
得到局部G-凸一致空间上具有S-KKM性质的集值映射的新的几乎不动点定理和不动点定理.我们的结果对已有文献中的相应结论进行了改进和一般化.  相似文献   

18.
给出将广义判断矩阵排序向量的计算及一致性检验转化为普通判断矩阵的相应计算的具体算法 .  相似文献   

19.
关于几乎等距嵌入的一个注记   总被引:2,自引:0,他引:2  
定光桂 《数学学报》2001,44(2):273-276
本文将指出:对于足够小的ε> 0,不存在从无穷维“抽象 LP”空 间(0< p<∞)到空间(c)的ε-等距线性算子.  相似文献   

20.
In this paper, we mainly discuss some generalized metric properties and the cardinal invariants of almost topological groups. We give a characterization for an almost topological group to be a topological group and show that:(1) Each almost topological group that is of countable π-character is submetrizable;(2) Each left λ-narrow almost topological group isλ-narrow;(3) Each separable almost topological group is ω-narrow. Some questions are posed.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号