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1.
In this paper, we prove that almost all circulant digraphs are strongly connected. Furthermore, for any given positive integer m, we show that almost every circulant digraph C has connectivity at least m/1 m(d(C) 1), where d(C) is the vertex degree of C.  相似文献   

2.
A locally semicomplete digraph is a digraph D=(V,A) satisfying the following condi-tion for every vertex x∈V the D[O(x)] and D[I(x)] are semicomplete digraphs. In this paper,we get some properties of cycles and determine the exponent set of primitive locally semicompleted digraphs.  相似文献   

3.
In this paper,we characterize the pointwise rate of convergence for the combinations of the Baskakov operators using the Ditzian-Totkik modulus of smoothness.  相似文献   

4.
In this paper, we characterize the pointwise rate of convergence for the combinations of the Baskakov operators using the Ditzian-Totik modulus of smoothness.  相似文献   

5.
In this paper, we characterize the trees with the largest Laplacian and adjacency spectral radii among all trees with fixed number of vertices and fixed maximal degree, respectively.  相似文献   

6.
In this paper, we investigates the existence of positive solutions for a class of quasilinear elliptic equations by using the topological degree argument.  相似文献   

7.
In this paper we give theorems on the degree of approximation of functions of one and two variables by certain operators of the Szasz-Mirakyan type.  相似文献   

8.
In this paper,we study a non-autonomous ratio-dependent predator-prey model with predator's harvest.By means of the coincidence degree theory,we establish sufficient conditions for the existence of at least two positive periodic solutions of this model.  相似文献   

9.
卢玉峰 《东北数学》2001,17(4):461-468
In this paper we characterize the essential spectra of Toeplitz operators on Bergman spaces by using Douglas‘ localization Theorem and obtain the local decomposition of the essential spectra of Toeplitz operators.  相似文献   

10.
In this article,we characterize the boundedness from below of multiplication operators between α-Bloch spaces on the unit ball.  相似文献   

11.
CONNECTIVITIESOFRANDOMCIRCULANTDIGRAPHS¥MENGJIXIANGANDHUANGQIONGXIANGAbstract:Inthispaperlweprovethatalmostallcirculantdigrap...  相似文献   

12.
In this paper, we completely determine the connectivity of every infinite circulant digraphs and prove that almost all infinite circulant digraphs are infinitely strongly connected and therefore have both one- and two-way infinite Hamiltonian paths. Received February 4, 1998, Accepted May 16, 2002  相似文献   

13.
Knödel graphs form a class of bipartite incident-graph of circulant digraphs. This class has been extensively studied for the purpose of fast communications in networks, and it has deserved a lot of attention in this context. In this paper, we show that there exists an O(n log5 n)-time algorithm to recognize Knödel graphs of order 2n. The algorithm is based on a characterization of the cycles of length six in these graphs (bipartite incident-graphs of circulant digraphs always have cycles of length six). A consequence of our result is that the circulant digraphs whose chords are the power of two minus one can be recognized in O(n log5 n) time.  相似文献   

14.
Circulant digraphs determined by their spectra   总被引:1,自引:0,他引:1  
Inspired by Ádám's conjecture the isomorphism problem of circulant digraphs is widely investigated. In the literature, the spectrum method was to solve the isomorphism problem for the circulants of prime-power order by some people. In this paper, we develop the spectrum method to characterize the circulant digraphs of orders pa and paqb, where p and q are distinct primes.  相似文献   

15.
The spectrum of a digraph in general contains real and complex eigenvalues. A digraph is called a Gaussian integral digraph if it has a Gaussian integral spectrum that is all eigenvalues are Gaussian integers. In this paper, we consider Gaussian integral digraphs among circulant digraphs.  相似文献   

16.
本文刻划了所有4度有向和无内循环图.  相似文献   

17.
4-tegular symmetric circulant digraphs and graphs are classified in this paper.  相似文献   

18.
(1). We determine the number of non-isomorphic classes of self-complementary circulant digraphs with pq vertices, where p and q are distinct primes. The non-isomorphic classes of these circulant digraphs with pq vertices are enumerated. (2). We also determine the number of non-isomorphic classes of self-complementary, vertex-transitive digraphs with a prime number p vertices, and the number of self-complementary strongly vertex-transitive digraphs with p vertices. The non-isomorphic classes of strongly vertex-transitive digraphs with p vertices are also enumerated.  相似文献   

19.
This paper deals with Hamiltonicity of connected loopless circulant digraphs of outdegree three with connection set of the form {a,ka,c}, where k is an integer. In particular, we prove that if k=−1 or k=2 such a circulant digraph is Hamiltonian if and only if it is not isomorphic to the circulant digraph on 12 vertices with connection set {3,6,4}.  相似文献   

20.
It is well known that Moore digraphs do not exist except for trivial cases (degree 1 or diameter 1), but there are digraphs of diameter two and arbitrary degree which miss the Moore bound by one. No examples of such digraphs of diameter at least three are known, although several necessary conditions for their existence have been obtained. In this paper, we prove that digraphs of degree three and diameter k ≥ 3 which miss the Moore bound by one do not exist. © 2004 Wiley Periodicals, Inc. J Graph Theory 48: 112–126, 2005  相似文献   

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