全文获取类型
收费全文 | 159篇 |
免费 | 3篇 |
国内免费 | 2篇 |
专业分类
化学 | 1篇 |
力学 | 4篇 |
数学 | 155篇 |
物理学 | 4篇 |
出版年
2023年 | 6篇 |
2022年 | 5篇 |
2021年 | 1篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 1篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 6篇 |
2012年 | 1篇 |
2011年 | 15篇 |
2010年 | 10篇 |
2009年 | 23篇 |
2008年 | 10篇 |
2007年 | 6篇 |
2006年 | 9篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1982年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有164条查询结果,搜索用时 0 毫秒
21.
Alewyn P. Burger 《Discrete Mathematics》2009,309(8):2473-2036
The relationship ρL(G)≤ρ(G)≤γ(G) between the lower packing number ρL(G), the packing number ρ(G) and the domination number γ(G) of a graph G is well known. In this paper we establish best possible bounds on the ratios of the packing numbers of any (connected) graph to its six domination-related parameters (the lower and upper irredundance numbers ir and IR, the lower and upper independence numbers i and β, and the lower and upper domination numbers γ and Γ). In particular, best possible constants aθ, bθ, cθ and dθ are found for which the inequalities and hold for any connected graph G and all θ∈{ir,γ,i,β,Γ,IR}. From our work it follows, for example, that and for any connected graph G, and that these inequalities are best possible. 相似文献
22.
We construct an example of a nonseparable Banach space which does not admit a support set.2 It is a consistent (and necessarily independent from the axioms of ZFC) example of a space C(K) of continuous functions on a compact Hausdorff K with the supremum norm. The construction depends on a construction of a Boolean algebra with some combinatorial properties. The space is also hereditarily Lindelöf in the weak topology but it doesn't have any nonseparable subspace nor any nonseparable quotient which is a C(K) space for K dispersed. 相似文献
23.
Jens-P. Bode 《Discrete Mathematics》2003,272(1):27-35
For three kinds of chess-like knights, one on triangle and two on hexagon boards, the independence numbers for their knight graphs are considered. We determine these numbers completely for two kinds of these knights, and for one residue class modulo 4 in the case of the third kind. 相似文献
24.
For some integer k0 and two graph parameters π and τ, a graph G is called πτ(k)-perfect, if π(H)−τ(H)k for every induced subgraph H of G. For r1 let αr and γr denote the r-(distance)-independence and r-(distance)-domination number, respectively. In (J. Graph Theory 32 (1999) 303–310), I. Zverovich gave an ingenious complete characterization of α1γ1(k)-perfect graphs in terms of forbidden induced subgraphs. In this paper we study αrγs(k)-perfect graphs for r,s1. We prove several properties of minimal αrγs(k)-imperfect graphs. Generalizing Zverovich's main result in (J. Graph Theory 32 (1999) 303–310), we completely characterize α2r−1γr(k)-perfect graphs for r1. Furthermore, we characterize claw-free α2γ2(k)-perfect graphs. 相似文献
25.
A class K of structures is controlled if for all cardinals λ, the relation of L∞,λ-equivalence partitions K into a set of equivalence classes (as opposed to a proper class). We prove that no pseudo-elementary class with the independence property is controlled. By contrast, there is a pseudo-elementary class with the strict order property that is controlled (see Arch. Math. Logic 40 (2001) 69–88). 相似文献
26.
The problem of dependency between two random variables has been studied throughly in the literature. Many dependency measures have been proposed according to concepts such as concordance, quadrant dependency, etc. More recently, the development of the Theory of Copulas has had a great impact in the study of dependence of random variables specially in the case of continuous random variables. In the case of the multivariate setting, the study of the strong mixing conditions has lead to interesting results that extend some results like the central limit theorem to the case of dependent random variables.In this paper, we study the behavior of a multidimensional extension of two well-known dependency measures, finding their basic properties as well as several examples. The main difference between these measures and others previously proposed is that these ones are based on the definition of independence among n random elements or variables, therefore they provide a nice way to measure dependency.The main purpose of this paper is to present a sample version of one of these measures, find its properties, and based on this sample version to propose a test of independence of multivariate observations. We include several references of applications in Statistics. 相似文献
27.
A bouquet of matroids is a combinatorial structure that generalizes the properties of matroids. Given an independence system, there exist several bouquets of matroids having the same family of independent sets. We show that the collection of these geometries forms in general a meet semi-lattice and, in some cases, a lattice (for instance, when is the family of the stable sets in a graph). Moreover, one of the bouquets that correspond to the highest elements in the meet semi-lattice provides the smallest decomposition of into matroidal families, such that the rank functions of the different matroids have the same values for common sets. In the last section, we give sharp bounds on the performance of the greedy algorithm, using parameters of some special bouquets in the semi-lattice. 相似文献
28.
Reinhardt Euler 《Mathematical Programming》1982,24(1):269-283
Let (E,I) be an independence system over the finite setE = {e
1, ,e
n
}, whose elements are orderede
1 e
n
. (E,I) is called regular, if the independence of {e
l
, ,e
l
k
},l
1 < <l
k
, implies that of {e
m
l
, ,e
m
k
}, wherem
l
< ··· <m
k
andl
1 m
1, ,l
k
m
k
. (E,I) is called a 2-system, if for anyI I,e E I the setI {e } contains at most 2 distinct circuitsC, C I and the number 2 is minimal with respect to this property. If, in addition, for any two independent setsI andJ the family (C J, C
C
(J, I)), whereC(J, I) denotes {C C:e J I C
{e}}, can be partitioned into 2 subfamilies each of which possesses a transversal, then (E,I) is called a (2, 2)-system. In this paper we characterize regular 2-systems and we show that the classes of regular 2-systems resp. regular (2, 2)-systems are identical. 相似文献
29.
In this paper we introduce the concept of distance local connectivity of a graph. We give several sufficient conditions in terms of the independence number and of the vertex degrees, and we show a relation between the distance local connectivity and the hamiltonian index of a graph. 相似文献
30.
Cheng HU 《数学年刊B辑(英文版)》2018,39(5):791-804
This paper deals with strong laws of large numbers for sublinear expectation under controlled 1st moment condition. For a sequence of independent random variables, the author obtains a strong law of large numbers under conditions that there is a control random variable whose 1st moment for sublinear expectation is finite. By discussing the relation between sublinear expectation and Choquet expectation, for a sequence of i.i.d random variables, the author illustrates that only the finiteness of uniform 1st moment for sublinear expectation cannot ensure the validity of the strong law of large numbers which in turn reveals that our result does make sense. 相似文献