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关于有效点集的闭性和连通性   总被引:1,自引:0,他引:1  
本文的主要结果是,假设A是局部凸空间里的紧的F一集,则A的有效点集E(A|C)是闭集。需要提及的是,此结果中关于A并没有作任何凸性的假设,如果对它再附加某种凸性假设条件时,则本文进一步证明了有效点集E(A|C)不但是闭集,而且还是连通集。  相似文献   

3.
连续树映射的ω极限集与非游荡集   总被引:1,自引:0,他引:1  
周丽珍 《数学年刊A辑》2000,21(6):733-738
本文研究树上连续自映射f的ω极限集∧,非游荡集Ω的若干拓扑结构,主要证明了不在周期点集闭包中的ω极限点都有无限轨迹;Ω-  相似文献   

4.
本文研究树上连续自映射f的ω极限集Λ,非游荡集Ω的若干拓扑结构,主要证明了:不在周期点集闭包中的ω极限点都有无限轨迹;Ω-P,Ω-Γ为可数集,Λ-Γ,P-Γ或为空集或可数无限,其中Γ为f的γ极限集.  相似文献   

5.
本文用单叶函数中的面积定理及Garabedian-Schiffer不等式的有关推论.给出了求多项式的填充Julia集及Mandelbrot集面积的方法及直径的上界估计,从而给A.Douady所提的有关问题一个回答.  相似文献   

6.
扩张不变集相对非自治扰动的稳定性   总被引:1,自引:0,他引:1  
何连法 《数学学报》1994,37(5):621-624
本文研究了自映射的扩张不变集在C ̄0非自治扰动和C ̄1非自治扰动下的稳定性质。  相似文献   

7.
以Banach空间的一般凸集为研究对象,将Banach空间的凸性研究推广到了内部非空的凸集上.打破了从单位球出发研究Banach空间几何的具有局限性的研究方法,给出了严格凸集的若干特征刻画及性质,并得到了严格凸集和光滑集之间的对偶定理.  相似文献   

8.
Z.Pawlak粗集理论是一种研究和处理静态知识的静态粗集理论.提出研究和处理动态知识的动态粗集理论,给出动态粗集的数学表示,定义知识库上的元素迁移系数、D-粗集、D-近似集等概念,研究D-粗集的迁移特性,给出D-粗集退化定理、D-粗集转化定理、迁移平衡定理等,并进行实例分析和意义解析.D-粗集是Pawlak粗集的一般形式,而Pawlak粗集可以看作D-粗集的一种特例.  相似文献   

9.
强Raney偏序集   总被引:1,自引:1,他引:0  
引入强Raney偏序集的概念,讨论了强Raney偏序集的一些性质,证明了强Raney偏序集为超代数偏序集,定向完备的偏序集为强Raney偏序集当且仅当它既是Raney偏序集也是A-偏序集.  相似文献   

10.
一方面,需要全面了解馆藏文物腐蚀现状,科学分析和评估造成馆藏文物腐蚀损失的原因,为馆藏文物长期保护提供科学依据和对策;另一方面,文物的腐蚀又是具有多样性、复杂性及不间断性的,每一腐蚀程度之间的界限并非十分清晰,而是连续模糊的,这为全面了解馆藏文物腐蚀现状带来了很大困难.因此,建立科学的模型对文物遭受腐蚀侵害的真实情况做出准确的描述迫在眉睫,利用模糊综合评判及其逆问题给出了科学严谨的具体模型.  相似文献   

11.
A set S of vertices in a graph G = (V, E) is a total restrained dominating set (TRDS) of G if every vertex of G is adjacent to a vertex in S and every vertex of V − S is adjacent to a vertex in V − S. The total restrained domination number of G, denoted by γ tr (G), is the minimum cardinality of a TRDS of G. Let G be a cubic graph of order n. In this paper we establish an upper bound on γ tr (G). If adding the restriction that G is claw-free, then we show that γ tr (G) = γ t (G) where γ t (G) is the total domination number of G, and thus some results on total domination in claw-free cubic graphs are valid for total restrained domination. Research was partially supported by the NNSF of China (Nos. 60773078, 10832006), the ShuGuang Plan of Shanghai Education Development Foundation (No. 06SG42) and Shanghai Leading Academic Discipline Project (No. S30104).  相似文献   

12.
Let G = (V,E) be a graph and let S V. The set S is a packing in G if the vertices of S are pairwise at distance at least three apart in G. The set S is a dominating set (DS) if every vertex in VS is adjacent to a vertex in S. Further, if every vertex in VS is also adjacent to a vertex in VS, then S is a restrained dominating set (RDS). The domination number of G, denoted by γ(G), is the minimum cardinality of a DS of G, while the restrained domination number of G, denoted by γr(G), is the minimum cardinality of a RDS of G. The graph G is γ-excellent if every vertex of G belongs to some minimum DS of G. A constructive characterization of trees with equal domination and restrained domination numbers is presented. As a consequence of this characterization we show that the following statements are equivalent: (i) T is a tree with γ(T)=γr(T); (ii) T is a γ-excellent tree and TK2; and (iii) T is a tree that has a unique maximum packing and this set is a dominating set of T. We show that if T is a tree of order n with ℓ leaves, then γr(T) ≤ (n + ℓ + 1)/2, and we characterize those trees achieving equality.  相似文献   

13.
The open neighborhood N G (e) of an edge e in a graph G is the set consisting of all edges having a common end-vertex with e. Let f be a function on E(G), the edge set of G, into the set {−1, 1}. If for each eE(G), then f is called a signed edge total dominating function of G. The minimum of the values , taken over all signed edge total dominating function f of G, is called the signed edge total domination number of G and is denoted by γ st ′(G). Obviously, γ st ′(G) is defined only for graphs G which have no connected components isomorphic to K 2. In this paper we present some lower bounds for γ st ′(G). In particular, we prove that γ st ′(T) ⩾ 2 − m/3 for every tree T of size m ⩾ 2. We also classify all trees T with γ st ′(T). Research supported by a Faculty Research Grant, University of West Georgia.  相似文献   

14.
Total Domination in Graphs with Given Girth   总被引:1,自引:0,他引:1  
A set S of vertices in a graph G without isolated vertices is a total dominating set of G if every vertex of G is adjacent to some vertex in S. The minimum cardinality of a total dominating set of G is the total domination number γ t (G) of G. In this paper, we establish an upper bound on the total domination number of a graph with minimum degree at least two in terms of its order and girth. We prove that if G is a graph of order n with minimum degree at least two and girth g, then γ t (G) ≤ n/2 + n/g, and this bound is sharp. Our proof is an interplay between graph theory and transversals in hypergraphs. Michael A. Henning: Research supported in part by the South African National Research Foundation and the University of KwaZulu-Natal.  相似文献   

15.
A set S of vertices of a graph G = (V, E) without isolated vertex is a total dominating set if every vertex of V(G) is adjacent to some vertex in S. The total domination number γ t (G) is the minimum cardinality of a total dominating set of G. The total domination subdivision number is the minimum number of edges that must be subdivided (each edge in G can be subdivided at most once) in order to increase the total domination number. In this paper we prove that for every simple connected graph G of order n ≥ 3,
where d 2(v) is the number of vertices of G at distance 2 from v. R. Khoeilar: Research supported by the Research Office of Azarbaijan University of Tarbiat Moallem.  相似文献   

16.
Let G=(V,E) be a graph without an isolated vertex. A set DV(G) is a total dominating set if D is dominating, and the induced subgraph G[D] does not contain an isolated vertex. The total domination number of G is the minimum cardinality of a total dominating set of G. A set DV(G) is a total outer-connected dominating set if D is total dominating, and the induced subgraph G[V(G)−D] is a connected graph. The total outer-connected domination number of G is the minimum cardinality of a total outer-connected dominating set of G. We characterize trees with equal total domination and total outer-connected domination numbers. We give a lower bound for the total outer-connected domination number of trees and we characterize the extremal trees.  相似文献   

17.
Let G = (V, E) be a simple graph. A subset SV is a dominating set of G, if for any vertex uV-S, there exists a vertex vS such that uvE. The domination number, denoted by γ(G), is the minimum cardinality of a dominating set. In this paper we will prove that if G is a 5-regular graph, then γ(G) ⩽ 5/14n.  相似文献   

18.
Let G = (V, E) be a graph without isolated vertices. A set S lohtain in V is a domination set of G if every vertex in V - S is adjacent to a vertex in S, that is N[S] = V. The domination number of G, denoted by γ(G), is the minimum cardinality of a domination set of G. A set S lohtain in V is a paired-domination set of G if S is a domination set of G and the induced subgraph G[S] has a perfect matching. The paired-domination number, denoted by γpr(G), is defined to be the minimum cardinality of a paired-domination set S in G. A subset S lohtain in V is a power domination set of G if all vertices of V can be observed recursively by the following rules: (i) all vertices in N[S] are observed initially, and (ii) if an observed vertex u has all neighbors observed except one neighbor v, then v is observed (by u). The power domination number, denoted by γp(G), is the minimum cardinality of a power domination set of G. In this paper, the constructive characterizations for trees with γp=γ and γpr = γp are provided respectively.  相似文献   

19.
The bubble tree compactified instanton moduli space -Mκ (X) is introduced. Its singularity set Singκ(X) is described. By the standard gluing theory, one can show that- Mκ(X) - Singκ(X) is a topological orbifold. In this paper, we give an argument to construct smooth structures on it.  相似文献   

20.
Let G be a graph with vertex set V(G), and let k ⩾ 1 be an integer. A subset DV(G) is called a k-dominating set if every vertex υV(G)-D has at least k neighbors in D. The k-domination number γ k (G) of G is the minimum cardinality of a k-dominating set in G. If G is a graph with minimum degree δ(G) ⩾ k + 1, then we prove that
$ \gamma _{k + 1} (G) \leqslant \frac{{|V(G)| + \gamma _k (G)}} {2}. $ \gamma _{k + 1} (G) \leqslant \frac{{|V(G)| + \gamma _k (G)}} {2}.   相似文献   

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