模2N的0/1平衡背包的构造

证明了模2^N的0/1平衡背包与重量矩阵为上三角阵的标准平衡背包等价，且2^N(N-1)/2N!     

p-adic数域Q_p上的窗口Fourier变换

提出了 p-adic数域 Qp上的窗口 Fourier变换和逆变换 ,详细地讨论了 p-adic模函数和阶梯函数的窗口 Fourier变换和逆变换 ,最后给出了 p-adic模函数和阶梯函数的窗口 Fourier变换定理 .     

二重Laplace-Stieltjes变换的增长性*

本文引入了一种新的广义级来研究由二重Laplace-Stieltjes变换所定义的全纯函数的增长性, 并建立了一些最大模与最大项之间的有趣的关系,推广了Laplace-Stieltjes变换的某些结果.     

函数变换缩小数据级比偏差效果的比较原则

针对缩小序列级比偏差的单调变换,研究了在函数的和变换与每一个变换缩小级比偏差效果优劣的比较原则基础上证明了两函数之正线性和变换缩小级比偏差效果介于这两个函数缩小级比偏差效果之间.因此如果两函数之正线性和变换不比任何一个单独变换效果差,其实质是两函数商的比值是常数,即两函数变换缩小级比偏差效果一样好,并通过实例验证了结论.     

椭圆模函数与数域上三次类域的构造

本文利用2级椭圆模函数在模群基本区内某些点处的函数值来构造任意数域上的所有3次类域,同时导出本原的2级模函数的一个关系式,利用这个关系式给出构造虚二次域的某些类域的方法.     

右半平面上Laplace-Stieltjes变换的值分布

对右半平面上τ(2<τ<+∞)级Laplace-Stieltjes变换,在一定条件下,在虚轴上必有一个涉及小函数关于型函数的Borel点;对右半平面上无穷级Laplace-Stieltjes变换,在一定条件下,在虚轴上必有一个涉及小函数的无穷级Borel点.     

高阶(2+1)维Broer-Kaup方程的局域相干结构

利用推广的齐次平衡方法,研究高阶(2+1)维Broer-Kaup方程的局域相干结构.首先基于推广的齐次平衡方法,给出这个模型的一个非线性变换,并把它变换成一个线性化的方程.然后从线性化方程出发,构造出一个分离变量的拟解.由于拟解中不仅含有两个y的任意函数,而且还有{αi,βi,γk,kj,lk}和{N,M,L}这些参数可以任意选取,因此合适的选择这些函数和参数,可以得到新的相当丰富的孤子结构.方法直接而简单,可推广应用一大类(2+1)维非线性物理模.     

基于反余弦函数变换的灰色预测模型研究

提出了反余弦函数变换方法,证明了这种变换是级比压缩变换,能够提高序列光滑度,可以保持序列凹凸性,不会增大还原误差,满足数据变换的构造准则.通过具体算例表明,基于反余弦函数变换的GM(1,1)模型的预测精度优于传统GM(1,1)模型和基于幂函数变换的GM(1,1)模型,说明了该变换的有效性.     

基于函数arccos(px+q)变换的灰色预测模型研究

借助于函数变换理论和灰色系统建模理论,并结合反余弦函数和线性函数的特点,提出了反余弦函数和线性函数相结合的变换方法并建立了一个改进的GM(1,1)模型.证明了这种变换一方面能提高序列的光滑比并压缩序列的级比;另一方面可以使还原误差减小.具体算例结果表明,经过反余弦函数和线性函数相结合建立的改进GM(1,1)模型的拟合精度优于传统GM(1,1)模型和基于反余弦函数变换的GM(1,1)模型的拟合精度.     

关于具有负系数的p叶星象函数的注记

文献[1]的全部结果是对具有负系数的P叶α级星象函数类T(P,α)与P叶α级凸象函数类C(P,α)(0≤α相似文献   

On a Question of Phillips

In [5] Phillips proved that one can obtain the additive group of any nonstandard model *? of the ring ? of integers by using a linear mod 1 function h : F ?, where F is the α-dimensional vector space over ? when α is the cardinality of *?. In this connection it arises the question whether there are linear mod 1 functions which are neither addition nor quasi-linear. We prove that this is the case.     

Supermodular covering knapsack polytope

The supermodular covering knapsack set is the discrete upper level set of a non-decreasing supermodular function. Submodular and supermodular knapsack sets arise naturally when modeling utilities, risk and probabilistic constraints on discrete variables. In a recent paper Atamtürk and Narayanan (2009) study the lower level set of a non-decreasing submodular function.In this complementary paper we describe pack inequalities for the supermodular covering knapsack set and investigate their separation, extensions and lifting. We give sequence-independent upper bounds and lower bounds on the lifting coefficients. Furthermore, we present a computational study on using the polyhedral results derived for solving 0–1 optimization problems over conic quadratic constraints with a branch-and-cut algorithm.     

On the exact separation of mixed integer knapsack cuts

During the last decades, much research has been conducted on deriving classes of valid inequalities for mixed integer knapsack sets, which we call knapsack cuts. Bixby et?al. (The sharpest cut: the impact of Manfred Padberg and his work. MPS/SIAM Series on Optimization, pp. 309?C326, 2004) empirically observe that, within the context of branch-and-cut algorithms to solve mixed integer programming problems, the most important inequalities are knapsack cuts derived by the mixed integer rounding (MIR) procedure. In this work we analyze this empirical observation by developing an algorithm to separate over the convex hull of a mixed integer knapsack set. The main feature of this algorithm is a specialized subroutine for optimizing over a mixed integer knapsack set which exploits dominance relationships. The exact separation of knapsack cuts allows us to establish natural benchmarks by which to evaluate specific classes of them. Using these benchmarks on MIPLIB 3.0 and MIPLIB 2003 instances we analyze the performance of MIR inequalities. Our computations, which are performed in exact arithmetic, are surprising: In the vast majority of the instances in which knapsack cuts yield bound improvements, MIR cuts alone achieve over 87% of the observed gain.     

Estimation of production technology when the objective is to maximize return to the outlay

This paper deals with estimation of production technology where endogeneous choice of input and output variables is explicitly recognized. To address this endogeneity issue, we assume that producers maximize return to the outlay. We start from a flexible (translog) transformation function with a single output and multiple inputs and show how the first-order conditions of maximizing return to the outlay can be used to come up with an ‘estimating equation’ that does not suffer from the econometric endogeneity problem although the output and input variables are chosen endogenously. This is because the regressors in this estimating equation are in ratio forms which are uncorrelated with the error term under the assumption that producers maximize return to the outlay. The analysis is then extended to the multiple outputs and multiple inputs case with technical inefficiency. Although the estimating equations in both single and multiple output cases are neither production nor distance functions, they can be estimated in a straightforward manner using the standard stochastic frontier technique without worrying about endogeneity of the regressors. Thus, we provide a rationale for estimating the technology parameters consistently using an econometric model which requires data on only input and output quantities.     

Analysis of maximum total return in the continuous knapsack problem with fuzzy object weights

This paper proposes a parametric programming approach to analyze the fuzzy maximum total return in the continuous knapsack problem with fuzzy objective weights, in that the membership function of the maximum total return is constructed. The idea is based on Zadeh’s extension principle, α-cut representation, and the duality theorem of linear programming. A pair of linear programs parameterized by possibility level α is formulated to calculate the lower and upper bounds of the fuzzy maximum total return at α, through which the membership function of the maximum total return is constructed. To demonstrate the validity of the proposed procedure, an example studied by the previous studies is investigated successfully. Since the fuzzy maximum total return is completely expressed by a membership function rather than by a crisp value reported in previous studies, the fuzziness of object weights is conserved completely, and more information is provided for making decisions in real-world resource allocation applications. The generalization of the proposed approach for other types of knapsack problems is also straightforward.     

Universal sums of three quadratic polynomials

Let a,b,c,d,e and f be integers with a≥ c≥ e> 0,b>-a and b≡a(mod 2),d>-c and d≡c(mod 2),f>-e and f≡e(mod 2).Suppose that b≥d if a=c,and d≥f if c=e.When b(a-b),d(c-d) and f(e-f) are not all zero,we prove that if each n∈N={0,1,2,...} can be written as x(ax+b)/2+y(cy+d)/2+z(ez+f)/2 with x,y,z∈N then the tuple(a,b,c,d,e,f) must be on our list of 473 candidates,and show that 56 of them meet our purpose.When b∈[0,a),d∈[0,c) and f∈[0,e),we investigate the universal tuples(a,b,c,d,e,f) over Z for which any n∈N can be written as x(ax+b)/2+y(cy+d)/2+z(ez+f)/2 with x,y,z∈Z,and show that there are totally 12,082 such candidates some of which are proved to be universal tuples over Z.For example,we show that any n∈N can be written as x(x+1)/2+y(3y+1)/2+z(5z+1)/2 with x,y,z∈Z,and conjecture that each n∈N can be written as x(x+1)/2+y(3y+1)/2+z(5z+1)/2 with x,y,z∈N.     

一个素数和一个素数的平方和问题

H表示一个正整数N的集合,使对任意的正整数q,同余方程a+b~2≡N(mod q)在模q的既约剩余系中有解a;b.E(x)表示N≤x,N∈H,但不能表成p_1+p_2~2=N的数的个数,其中p_1,p_2个表示素数,则E(x)<相似文献   

关于$3\times 3$阶三角矩阵环上模的研究

文章对$3\times 3$阶三角矩阵环$$\Gamma = \left(\begin{array}{ccc}T & 0 & 0 \\M & U & 0\\{N \otimes _U M} & N & V \\\end{array}\right)$$上的模作了研究,其中T,U,V均是环, M,N分别是U-T, V-U双模.通过用一个五元组$(A,B,C;f,g)$来描述一个左$\Gamma$-模 (其中$A \in \mod T, B\in {\rm mod} U, C \in {\rm mod} V$, $f:M \otimes _T A \to B \in {\rm mod} U, g:N \otimes _U B \to C \in {\rm mod} V$), 文章分别刻画了$\Gamma$上的一致模、空的模、有限嵌入模,并且确定了${ }_\Gamma (A \oplus B \oplus C)$的根和基座．     

On the supermodular knapsack problem

In this paper we introduce binary knapsack problems where the objective function is nonlinear, and investigate their Lagrangean and continuous relaxations. Some of our results generalize previously known theorems concerning linear and quadratic knapsack problems. We investigate in particular the case in which the objective function is supermodular. Under this hypothesis, although the problem remains NP-hard, we show that its Lagrangean dual and its continuous relaxation can be solved in polynomial time. We also comment on the complexity of recognizing supermodular functions. The particular case in which the knapsack constraint is of the cardinality type is also addressed and some properties of its optimal value as a function of the right hand side are derived.Work done while the authors were visiting Rutgers University.