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1.
In this paper, the necessary and sufficient conditions for the existence of a (gv, g, 3, λ)-difference family in Z gv are established. As a consequence, the existence spectrum of a cyclic (3, λ)-GDD of type g v without short orbits is determined. This work was supported by National Natural Science Foundation of China (Grants Nos. 10771013, 10831002)  相似文献   

2.
In this paper, we propose approximations to compute the steady-state performance measures of the M/GI/N+GI queue receiving Poisson arrivals with N identical servers, and general service and abandonment-time distributions. The approximations are based on scaling a single server M/GI/1+GI queue. For problems involving deterministic and exponential abandon times distributions, we suggest a practical way to compute the waiting time distributions and their moments using the Laplace transform of the workload density function. Our first contribution is numerically computing the workload density function in the M/GI/1+GI queue when the abandon times follow general distributions different from the deterministic and exponential distributions. Then we compute the waiting time distributions and their moments. Next, we scale-up the M/GI/1+GI queue giving rise to our approximations to capture the behavior of the multi-server system. We conduct extensive numerical experiments to test the speed and performance of the approximations, which prove the accuracy of their predictions.   相似文献   

3.
In this note, we show that the number of composite integers n ≤ x such that φ(n)|n - 1 is at most O(x^1/2(loglog x)^1/2), thus improving earlier results by Pomerance and by Shan.  相似文献   

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Let ƒ be a transcendental meromorphic function, a a nonzero finite complex number, and n ⩾ 2 a positive integer. Then ƒ + a(ƒ′) n assumes every complex value infinitely often. This answers a question of Ye for n = 2. A related normality criterion is also given. This work was supported by the National Natural Science Foundation of China (Grant No. 10771076), the Natural Science Foundation of Guangdong Province, China (Grant No. 07006700) and by the German-Israeli Foundation for Scientific Research and Development (Grant No. G-809-234.6/2003)  相似文献   

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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   

8.
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   

9.
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   

10.
 We give a characterization of strongly compact cardinals in terms of Q κ λ. We also prove that weakly normal Q-measures on Q κ λ are ⊂κ-normal. Received: 29 September 2000 / Revised version: March 2002 Published online: 5 November 2002 This project is supported by the New Zealand Marsden Fund. The author wishes to thank the referee for numerous comments and suggestions which have been incorporated into this version of the paper.  相似文献   

11.
We derive fast recursions to compute the probability that k or more consecutive customer losses take place during a busy period of a queue, the so called k-CCL probability, for regular and oscillating M X /G/1/n systems.  相似文献   

12.
The definition of lacunary strongly convergence is extended to the definition of lacunary strong (A σ , p)-convergence with respect to invariant mean when A is an infinite matrix and p = (p i ) is a strictly positive sequence. We study some properties and inclusion relations.  相似文献   

13.
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   

14.
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   

15.
Characterizations and properties of $ \mathcal{I}_g $ \mathcal{I}_g -closed sets and $ \mathcal{I}_g $ \mathcal{I}_g -open sets are given. A characterization of normal spaces is given in terms of $ \mathcal{I}_g $ \mathcal{I}_g -open sets. Also, it is established that an $ \mathcal{I}_g $ \mathcal{I}_g -closed subset of an $ \mathcal{I} $ \mathcal{I} -compact space is $ \mathcal{I} $ \mathcal{I} -compact.  相似文献   

16.
In this paper we construct a simply connected, minimal, complex surface of general type with p g =0 and K 2=2 using a rational blow-down surgery and a ℚ-Gorenstein smoothing theory. Mathematics Subject Classification (2000) Primary 14J29; Secondary 14J10, 14J17, 53D05  相似文献   

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Summary In [6] we introduced and investigated the notions of fI -sets and fI -continuous functions in ideal topological spaces. In this paper, we investigate their further important properties.  相似文献   

19.
We study Besicovitch-type spaces of generalized almost periodic functions. The main result is a theorem on representation of linear continuous functionals that is similar to the classical result of F. Riesz.  相似文献   

20.
We establish conditions for the oscillation of solutions of the equation y″ + p(t)Ay = 0 in a Banach space, where A is a bounded linear operator and p: ℝ+ → ℝ+ is a continuous function. __________ Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 59, No. 4, pp. 571–576, April, 2007.  相似文献   

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