关于M/G/l随机服务系统中L.Takacs引理的证明

L. Takacs' Lemma (ef [1] PP47-48) is a very important tool for the investigation of the transient behavior of the M/G/1 System. But the original proof contains a gap when γ(s, w) is expanded into Lagrange series by means of Lagrange theorem as given in the appendix of [1]. This is due to the fact that φ(s)=∫₀^∞e^-sxdH(x), the Laplace transform of the service time distribution , may not be analytic at s=0. An example of such a distrbution function H(x) is gives and a specific Lagrange theorem is proved By using this specific theorem, the gap in the original proof of Takacs′ Lemms is eliminated.     

Erratum to: Every Banach space admits a homogenous measure of non-compactness not equivalent to the Hausdorff measure

正[1, Theorem 4.4] states that every infinite dimensional Banach space admits a homogenous measure of noncompactness not equivalent to the Hausdorff measure. Howevere, there is a gap in the proof. In fact,we found that [1, Lemma 4.3] is not true. In this erratum, we give a corrected proof of [1, Theorem 4.4].     

Improved Hörmander’s theorem and new methods for oscillatory integral operators

This paper proves a theorem on the decay rate of the oscillatory integral operator with a degenerate C^∞ phase function, thus improving a classical theorem of HSrmander. The proof invokes two new methods to resolve the singularity of such kind of operators： a delicate method to decompose the operator and balance the L^2 norm estimates; and a method for resolution of singularity of the convolution type. The operator is decomposed into four major pieces instead of infinite dyadic pieces, which reveals that Cotlar＇s Lemma is not essential for the L^2 estimate of the operator. In the end the conclusion is further improved from the degenerate C^∞ phase function to the degenerate C^4 phase function.     

Cyclical Deformations of Quadrangles in S_κ~2 and Defining Properties of Alexandrov Spaces

This paper is mainly devoted to proving the four equivalent defining properties of a CBA(κ)space.The proof is based on an interesting tool we established which describes the cyclical five-step deformation procedure for quadrangles in the model 2-plane S_κ~2, including the limit shape of each step.As a byproduct we give a complete list of cyclical deformation procedures for all kinds of quadrangles on S_1~2.At last we make a contrast of geometric properties of CBA with CBB spaces, including a comparison between their defining properties and a discussion about Alexandrov's Lemma.     

A DETERMINANT FOR THE TRANSFER MATRIX OF THE ONE-DIMENSIONAL DIRECTED BOND PERCOLATION WITH FURTHER NEIGHBOUR BONDS

The rigorous proof of the relation det is given. This relation has been used to obtain the exact critical surface and the correlation length exponents of the one-dimensional directed bond percolation problem with bonds connecting 1～Lth nearest neighbours. A~((L)) is related to the transfer-matrix by (7). q_i is related to the occupation probability of the i-th nearest neighbour bond p_i by q_i=1-p_i (i=1, 2, ..., L). f_L is a multi-varlable polynomial in q_4's.     

THE OPTIMAL STOPPING PROBLEM OF A CONTINUOUS PARAMETER PROCESS

Suppose X = (Xr, Fr, t ∈ R+) be an optional reward process with ( Fr) satisfying usual conditions. In this paper, we correct the proof of existence about Snell envelope in [4] and the proof of an important lemma (Lemma 4. 6) in [5], and give a proof of existence about Snell envelope under certain conditions, i. e. EZx- < ∞ and Z is upper-semi-continuous on the right (USCR) or there is a stopping rule (SR)τ ≤σ such that EZx-∞ for any stopping rule σ . At the same time, we prove a four-repeated limit theorem when Z is continuous on the right. The character and the uniqueness of the optimal stopping time (OST) or optimal stopping rule (OSR) are discussed.     

A SIMPLE PROOF OF THE INEQUALITY FFD (L)≤11/9 OPT(L) 1, ■L FOR THE FFD BIN-PACKING ALGORITHM

The first fit decreasing (FFD) heuristic algorithm is one of the most famous and moststudied methods for an approximative solution of the bin-packing problem. For a list L, letOPT(L) denote the minimal number of bins into which L can be packed, and let FFD(L)denote the number of bins used by FFD. Johnson showed that for every list L, FFD(L)≤11/9OPT(L) 4. His proof required more than 100 pages. Later, Baker gave a much shorterand simpler proof for FFD(L)≤11/9OPT(L) 3. His proof required 22 pages. In this paper,we give a proof for FFD(L)≤11/9 OPT(L) 1. The proof is much simpler than the previousones.     

ON THE GENERALIZATIONS OF KALANDIA''''S LEMMA

Based on Bernstein's Theorem, Kalandia's Lemma describes the error estimate and the smoothness of the remainder under the second part of Holder norm when a Holder function is approximated by its best polynomial approximation. In this paper, Kalandia's Lemma is generalized to the cases that the best polynomial is replaced by one of its four kinds of Chebyshev polynomial expansions, the error estimates of the remainder are given out under Holder norm or the weighted Holder norms.     

Convergence to a Single Wave in the Fisher-KPP Equation(Dedicated to Haim Brezis,with admiration and respect)

The authors study the large time asymptotics of a solution of the Fisher-KPP reaction-diffusion equation, with an initial condition that is a compact perturbation of a step function. A well-known result of Bramson states that, in the reference frame moving as 2t-(3/2 )log t+x∞, the solution of the equation converges as t → +∞ to a translate of the traveling wave corresponding to the minimal speed c_* = 2. The constant x∞ depends on the initial condition u(0, x). The proof is elaborate, and based on probabilistic arguments.The purpose of this paper is to provide a simple proof based on PDE arguments.     

Erratum to: Remarks on lines and minimal rational curves

<正>Erratum to:Science in China Series A:Mathematics,April 2009 Vol.52 No.4:617–630doi:10.1007/s11425-009-0038-2There is a mistake in the proof of[1,Lemma 2.2],which occurs in 4-th line at[1,p.619],     

关于一类随机矩阵特征根极限分布的注记

一 引言 考虑k个p维总体X_1,X_2,…,X_k。假定它们都服从正态分布,其均值向量分别是(ξ_(1i),ξ_(2i),…,ξ_(pi)),i=1,2,…,k,且具有共同的协方差矩阵∑=(σ_(ij)),i,j=1,2,…,p。考虑矩阵     

A proof of the Morse-Bott Lemma

It is often said that the Morse-Bott Lemma can be viewed as a “parameterized” Morse Lemma, and its proof should follow from the differentiability of the methods used to prove the Morse Lemma. The goal of this expository paper is to fill in the details. We present Palais' proof of the Morse Lemma using Moser's path method, which yields the necessary differentiability.     

关于Caflisch的一个不等式

Caflisch[1，2]在Euler方程存在光滑解的假设下，证明了Boltzmann方程存在一个解，且该解在平均自由程趋于零的极限下与Euler解一致．不幸的是Caflisch的证明有错误，其关键的引理6．1的结论太弱，不足以完成主要定理的证明．事实上，Caflisch在证明主要定理时，使用了比引理6．1更强的结论，但并未说明．本文改进了Caflisch的一个重要不等式；加强了原引理6．1的结论，并在修正了原主要定理证明过程中的其它错误后完成了它的证明．     

A combinatorial proof of the Removal Lemma for Groups

Green [B. Green, A Szemerédi-type regularity lemma in abelian groups, with applications, Geom. Funct. Anal. 15 (2005) 340-376] established a version of the Szemerédi Regularity Lemma for abelian groups and derived the Removal Lemma for abelian groups as its corollary. We provide another proof of his Removal Lemma that allows us to extend its statement to all finite groups. We also discuss possible extensions of the Removal Lemma to systems of equations.     

A short proof of the wonderful lemma

The Wonderful Lemma, that was first proved by Roussel and Rubio, is one of the most important tools in the proof of the Strong Perfect Graph Theorem. Here we give a short proof of this lemma.     

A note on kernels and Sperner’s Lemma

The kernel-solvability of perfect graphs was first proved by Boros and Gurvich, and later Aharoni and Holzman gave a shorter proof. Both proofs were based on Scarf’s Lemma. In this note we show that a very simple proof can be given using a polyhedral version of Sperner’s Lemma. In addition, we extend the Boros–Gurvich theorem to h-perfect graphs and to a more general setting.     

图表追踪的一种机器实现方法

交换图表追踪法是同调代数中一种重要的证明方法.本文提出了一种基于前推的交换图表追踪的机器实现方法,它可以证明同调代数中一系列基于交换图的定理.该方法从定理的结论出发,通过构造辅助元素以及对辅助元素进行推导,能在有限步内给出定理的证明.本文提出的前推方法已经在Java开发平台上实现,同调代数中的五引理、九引理、蛇引理等的证明都可以由我们的程序自动产生.     

A proof of the Borsuk Antipodal Theorem

By applying simple properties of the Brouwer degree, a new and self-contained proof of the Antipodal Theorem of Borsuk is presented. The proof uses elementary notions of the simplicial topology but has points in common with analytical arguments based on the application of Sard's Lemma.     

精确分布推导的一个基本的方法

寻求统计量的精确分布,在数理统计的理论中是一个重要的问题。然而,在多元统计分析中,往往很不容易得到统计量的精确分布,有些统计量的分布,例如非中心的Wishanrt分布,持续了几十年,还没有获得完满的结果。我国的许宝騄先生早在1939年,就得到了正态总体样本协差阵的特征根的联合分布(参看[1])。据徐钟济先生的回忆,当时R.A.     

A note on the short algebraic proof of Farkas' Lemma

The author published ‘A Short Algebraic Proof of the Farkas Lemma’ [SIAM J. Optim. 19 (2008), pp. 234–239]. The author then found, in his opinion, a better exposition of the proof. He would therefore like to publish the new form of the proof in this note.