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1.
An f-coloring of a graph G is an edge-coloring of G such that each color appears at each vertex v V(G) at most f(v) times. The minimum number of colors needed to f-color G is called the f-chromatic index of G and is denoted by X′f(G). Any simple graph G has the f-chromatic index equal to △f(G) or △f(G) + 1, where △f(G) =max v V(G){[d(v)/f(v)]}. If X′f(G) = △f(G), then G is of f-class 1; otherwise G is of f-class 2. In this paper, a class of graphs of f-class 1 are obtained by a constructive proof. As a result, f-colorings of these graphs with △f(G) colors are given.  相似文献   

2.
Let S be a pomonoid and I a proper right ideal of S. In a previous paper, using the amalgamated coproduct A(I) of two copies of S S over I, we were able to solve one of the problems posed in S. Bulman-Fleming et al. (Commun. Algebra 34:1291–1317, 2006). In the present paper, we investigate further flatness properties of A(I). We also solve another problem stated in the paper cited above. Namely, we determine the condition under which Rees factor S-posets have property (P w ). Research supported by nwnu-kjcxgc-03-18.  相似文献   

3.
The idea of I-convergence was introduced by Kostyrko et al (2001) and also independently by Nuray and Ruckle (2000) (who called it generalized statistical convergence) as a generalization of statistical convergence (Fast (1951), Schoenberg(1959)). For the last few years, study of these convergences of sequences has become one of the most active areas of research in classical Analysis. In 2003 Muresaleen and Edely introduced the concept of statistical convergence of double sequences. In this paper we consider the notions of I and I*-convergence of double sequences in real line as well as in general metric spaces. We primarily study the inter-relationship between these two types of convergence and then investigate the category and porosity position of bounded I and I*-convergent double sequences. This work is funded by Council of Scientific and Industrial Research, HRDG, India.  相似文献   

4.
We describe a fairly general procedure for preserving I3 embeddings j: V λV λ via λ-stage reverse Easton iterated forcings. We use this method to prove that, assuming the consistency of an I3 embedding, V = HOD is consistent with the theory ZFC + WA where WA is an axiom schema in the language {∈, j} asserting a strong but not inconsistent form of “there is an elementary embedding VV”. This improves upon an earlier result in which consistency was established assuming an I1 embedding.   相似文献   

5.
We introduce the notion of categorical cliquish mapping and show that, for each K h C-mapping f: X × Y → Z, where X is a topological space, Y is a space with the first axiom of countability, and Z is a Moore space, with categorical-cliquish horizontal y-sections f y , the sets C y (f) are residual G δ-type sets in X for every y  Y. Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 60, No. 11, pp. 1539–1547, November, 2008.  相似文献   

6.
In this note we study the relation between k R -spaces and k-spaces and prove that a k R -space with a σ-hereditarily closure-preserving k-network consisting of compact subsets is a k-space, and that a k R -space with a point-countable k-network consisting of compact subsets need not be a k-space. This work was supported by the NSF of China (10271056).  相似文献   

7.
A generalization of density point with respect to category and I(J)-density topology has been presented in [5]. This papers deals with some basic properties of the corresponding I(J)-approximately continuous functions and gives answer when these functions are of the first Baire class and when they are Darboux functions.  相似文献   

8.
The main purpose of this paper is to introduce the concept of intuitionistic I-fuzzy quasi-coincident neighborhood systems of intuitiostic fuzzy points. The relation between the category of intuitionistic I-fuzzy topological spaces and the category of intuitionistic I-fuzzy quasi-coincident neighborhood spaces are studied. By using fuzzifying topology, the notion of generated intuitionistic I-fuzzy topology is proposed, and the connections among generated intuitionistic I-fuzzy topological spaces, fuzzifying topological spaces and I-fuzzy topological spaces are discussed. Finally, the properties of the operators Iω, ι are obtained.  相似文献   

9.
We consider some problems concerning the L p,q -cohomology of Riemannian manifolds. In the first part, we study the question of the normal solvability of the operator of exterior derivation on a surface of revolution M considered as an unbounded linear operator acting from Lpk (M) into Lk+1q (M). In the second part, we prove that the first L p,q-cohomology of the general Heisenberg group is nontrivial, provided that p < q. Received: 17 January 2006 Supported by INTAS (Grant 03–51–3251) and the State Maintenance Program for the Leading Scientific Schools of the Russian Federation (Grants NSh 311.2003.1, NSh 8526.2006.1).  相似文献   

10.
The hyperoperations, called theta-operations (δ), are motivated from the usual property, which the derivative has on the derivation of a product of functions. Using any map on a set, one can define δ-operations. In this paper, we continue our study on the δ-operations on groupoids, rings, fields and vector spaces or on the corresponding hyperstructures. Using δ-operations one obtains, mainly, Hwstructures, which form the largest class of the hyperstructures. For representation theory of hyperstructures, by hypermatrices, one needs special Hv-rings or Hy-fields, so these hyperstructures can be used. Moreover, we study the relation of these δ-structures with other classes of hyperstructures, especially with the Hv-structures.  相似文献   

11.
In this paper the author first introduce a new concept of L p -dual mixed volumes of star bodies which extends the classical dual mixed volumes. Moreover, we extend the notions of L p intersection body to L p -mixed intersection body. Inequalities for L p -dual mixed volumes of L p -mixed intersection bodies are established and the results established here provide new estimates for these type of inequalities. This work was supported by the Natural Science Foundation of Zhejiang Province of China (Grant No. Y605065) and the Foundation of the Education Department of Zhejiang Province of China (Grant No. 20050392)  相似文献   

12.
In this paper,we will use the 2r-th Ditzian-Totik modulus of smoothness wp^2r(f,t)p to discuss the direct and inverse theorem of approximation by Left-Bernstein-Durrmeyer quasi-interpolants Mn^[2r-1]f for functions of the space Lp[0,1](1≤p≤ ∞)。  相似文献   

13.
We investigate the growth of the Nevanlinna characteristic of f(z+η) for a fixed ηC in this paper. In particular, we obtain a precise asymptotic relation between T(r,f(z+η)) and T(r,f), which is only true for finite order meromorphic functions. We have also obtained the proximity function and pointwise estimates of f(z+η)/f(z) which is a discrete version of the classical logarithmic derivative estimates of f(z). We apply these results to give new growth estimates of meromorphic solutions to higher order linear difference equations. This also allows us to solve an old problem of Whittaker (Interpolatory Function Theory, Cambridge University Press, Cambridge, 1935) concerning a first order difference equation. We show by giving a number of examples that all of our results are best possible in certain senses. Finally, we give a direct proof of a result in Ablowitz, Halburd and Herbst (Nonlinearity 13:889–905, 2000) concerning integrable difference equations. This research was supported in part by the Research Grants Council of the Hong Kong Special Administrative Region, China (HKUST6135/01P). The second author was also partially supported by the National Natural Science Foundation of China (Grant No. 10501044) and the HKUST PDF Matching Fund.  相似文献   

14.
In this paper, we show, among other results, that if X is a [separable] locally compact space X [satisfying the first countability axiom] then the space Cc (X) has countable tightness [if and only if it has bounding tightness] if and only if it is Frechet-Urysohn, if and only if Cc (X) contains a dense (LM) subspace and if and only if X is a-compact.  相似文献   

15.
We show that meromorphic solutions f, g of f 2 + g 2 = 1 in C2 must be constant, if f z2 and g z1 have the same zeros (counting multiplicities). We also apply the result to characterize meromorphic solutions of certain nonlinear partial differential equations.  相似文献   

16.
The aim of this paper is to define the localization LM n -algebra of an LM n —algebra L with respect to a topology F on L; in Section 5 we prove that the maximal LM n -algebra of fractions (defined in [3]) and the LM n -algebra of fractions relative to an Λ—closed system (defined in Section 2) are LM n -algebras of localization.  相似文献   

17.
Let A be an Archimedean uniformly complete f-algebra with unit element. It is shown that A is a po-coherent ring (in the sense of F. Wehrung) if and only if A is Dedekind σ-complete. Received June 7, 2001; accepted in final form September 1, 2002.  相似文献   

18.
In this paper lower semicontinuity of the functional I(u)=∫ Ω f(x,u,Δ Hu)dx is investigated for f being a Carathéodory function defined on H n × R × R2n and for u∈SBV H (Ω), where H n is the Heisenberg group with dimension 2n+1, Ω∩H n is an open set and ∇ Hu denotes the approximate derivative of the absolute continuous part D a Hu with respect to D Hu. In addition, a Lusin type approximation theorem for a SBV H function is proved.  相似文献   

19.
Let D be a finite dimensional division algebra over a local field of characteristic p and let SL 1(D) denote the group of elements of reduced norm 1 in D. In this paper we prove that SL 1(D) is finitely presented as a profinite group. This work is part of the author’s Ph.D. Thesis at Yale University.  相似文献   

20.
For estimating the entropy of an absolutely continuous multivariate distribution, we propose nonparametric estimators based on the Euclidean distances between the n sample points and their k n -nearest neighbors, where {k n : n = 1, 2, …} is a sequence of positive integers varying with n. The proposed estimators are shown to be asymptotically unbiased and consistent.   相似文献   

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