基于多项式组主项解耦消元法的几何定理机器证明

基于多项式组主项解耦消元法 ,将几何定理的假设条件 (多项式组 PS)化为主项只含主变元的三角型多项式组 DTS,可得到定理命题成立的不含变元的非退化条件 ,即充分必要或更接近充分必要的非退化条件 .由于多项式主系数不含变元 ,已不存在 DTS多项式之间的约化问题 ,故方法有普遍意义 .文中例为西姆松定理的机器证明 .     

基于特征列方法和Wronskian行列式的曲面定理机器证明

将Chou与Gao的关于微分几何中曲线定理机器证明的方法推广到微分几何曲面定理中. 改进了经典的Wronskian行列式, 它可以用于判断微分域中的有限个元素是否在其常数域上线性相关. 基于Wronskian行列式, 可以用代数语言来描述微分几何曲面理论中的几何表述, 进而用特征列方法来证明这些定理.     

一类Riemann张量指标表达式的标准型完全分类及其在微分几何中的应用

本文研究了n维微分几何中Riemann张量指标表达式的标准型完全分类问题, 通过引入指标结构图的概念, 证明了规范类型单项式都是标准型, 并且构成次数不大于5 的Sakai类型单项式的正交基底, 由此得到Sakai类型单项式的标准型完全分类, 这是次数大于3时标准型完全分类问题的第一个结果. 同时给出了相应标准化算法, 通过比较说明了该算法比现有算法更加简便, 最后应用于自动推导和证明微分几何中关于Riemann张量的一些公式.     

基于张量乘积的快速谱元算法

针对椭圆型方程的谱元离散系统构造了一种基于张量乘积的快速直接解法．分析显示，新算法的计算量仅相当于迭代方法迭代Kx＋Ky次的计算量（这里Kx，Ky分别为x，y方向的区域剖分数），特别适合那些网格不多但多项式阶数较高的谱元离散．我们还将张量乘积方法推广到具有Neumann边界条件的奇异泊松问题的求解。给出了具体的实现方法．最后，利用张量乘积构造了变形区域上椭圆型方程的预条件子，数值结果显示预条件系统的条件数与多项式阶数无关．     

基于吴方法的几何定理证明的恒等式方法

多年来通常认为以吴方法为代表的几何定理机器证明的坐标法给出的证明不可读,或不是图灵意义下的类人解答.其实,只要对吴氏的算法做不多的改进,即将命题的结论多项式表示为其条件多项式的线性组合,就能获得不依赖于理论、算法和大量计算过程的恒等式明证.这样的恒等式可以转化为其他更简明且更有直观几何意义的点几何形式或向量及其他形式,从而获得多种证明方法.这也证明了点几何恒等式明证方法对等式型几何命题的普遍有效性.     

修正共轭梯度算法求解四元数Sylvester张量方程

本文提出一类张量形式的修正共轭梯度算法求解四元数Sylvester张量方程.证明在不计舍入误差的情况下,所提方法可在有限迭代步内获得张量方程组的解.进一步,通过选择特殊类型的初始张量,可获得方程组的唯一极小Frobenius范数解.通过数值算例验证了所提出算法的可行性和有效性.     

Четаев型非完整力学系统的微分几何原理

本文应用现代微分几何的方法研究Четаев型非完整力学系统.通过恰当地定义Четаев型约束Pfaff系统,给出了非完整力学系统的微分几何结构,从而将带有非完整约束的Lagrange方程表达为一种与坐标无关的不变形式,并且采用这个新观点讨论了约束的嵌入和非完整力学系统的守恒定律等问题,得到了约束子流形上的Noether型定理.     

一类初等微分几何定理机器证明的算法与实现

空间曲面上的曲线论是初等微分几何的重要部分．作者提出了一种以外微分运算和向量计算为主要工具,可以进行有关曲面上曲线局部性质的定理机器证明的算法．该算法结合了曲面上的活动标架,曲面上曲线的测地标架和曲线自身的Frenet标架,在Maple 9下得到实现．对20个例子进行的测试表明,由该算法生成的自动证明简短可读．     

一类三次多项式微分系统的周期解

根据Mironenko的反射函数理论,给出一种利用多项式方程探讨三次多项式微分系统周期解的几何性质的新方法.该文首先研究一类系统具有满足特定关系式的反射函数的结构,由此建立三次多项式微分系统与多项式方程之间的解的对应关系,然后利用此对应关系探讨三次多项式微分系统的周期解的几何性质.     

几何定理机器证明三十年

由于传统的兴趣和多种原因,几何定理的机器证明在自动推理的研究中占有重要的地位.自吴法发表至今30年,几何定理机器证明的研究和实践有了很大的进展.对无序几何命题而言,代数方法、数值方法均能有效地判定其真假,面积法(消点法)、搜索法更能生成其可读的证明.几何不等式机器证明的研究,由于多项式完全判别系统的建立,也有了突破.研究领域已由机器证明扩展为包括几何作图在内的一般几何问题的机器求解,并有了实际的应用.     

On a thermal stress problem for contacting half-spaces with inclusions of other material involving a new method for computing potentials and singular integrals

This paper deals with a thermal stress problem for contacting half-spaces of different materials having an inclusion of other material. With the aid of the contact tensor of two half spaces the problem is reduced to singular integral equations. Some new theorems on potentials with the contact tensor are used. Finally, a potential of the double layer with the contact tensor in the kernel and a singular integral operator, being the direct value of the potential, are calculated. For this a Kupradze method is applied, interpreting this potential as a solution of a contact problem of elastostatics. Some numerical experiments are communicated.     

Solving sparse non-negative tensor equations: algorithms and applications

We study iterative methods for solving a set of sparse non-negative tensor equations (multivariate polynomial systems) arising from data mining applications such as information retrieval by query search and community discovery in multi-dimensional networks. By making use of sparse and non-negative tensor structure, we develop Jacobi and Gauss-Seidel methods for solving tensor equations. The multiplication of tensors with vectors are required at each iteration of these iterative methods, the cost per iteration depends on the number of non-zeros in the sparse tensors. We show linear convergence of the Jacobi and Gauss-Seidel methods under suitable conditions, and therefore, the set of sparse non-negative tensor equations can be solved very efficiently. Experimental results on information retrieval by query search and community discovery in multi-dimensional networks are presented to illustrate the application of tensor equations and the effectiveness of the proposed methods.     

巴拿赫空间中线性离散时间系统的多项式二分性

本文给出了巴拿赫空间中线性差分方程的两个多项式二分性概念, 使其在相应空间中的范数的增长速度不快于指数型增长. 并用实例阐释了相关概念之间的关系. 借助于指数二分性的研究方法讨论了多项式二分性的特征, 所得结论推广了指数稳定性及指数二分性中的一些已有结果.     

求解混合三角多项式方程组的直接GBQ方法

许多科学与工程领域,我们经常需要求混合三角多项式方程组的全部解.一般来说,混合三角多项式方程组可以通过变量替换及增加二次多项式转化为多项式方程组,进而利用数值方法进行求解,但这种转化会增大问题的规模从而增加计算量.在本文中,我们不将问题转化,考虑利用直接同伦方法求解,并给出基于GBQ方法构造的初始方程组及同伦定理的证明.数值实验结果表明我们构造的直接同伦方法较已有的直接同伦方法更加有效.     

Some results in the theory of the vector ε-algorithm

The solution of systems of linear equations by mean of the vector ε-algorithm is investigated. The cases with a singular matrix are studied which show that, under certain assumptions on the minimal polynomial of the matrix, a solution can be obtained. Some theorems concerning the application of the ε-algorithm to vectors satisfying a matrix difference equation are proved. These results generalize results on the scalar ε-algorithm and some recent theorems on the vector ε-algorithm.     

Tensor eigenvalue complementarity problems

This paper studies tensor eigenvalue complementarity problems. Basic properties of standard and complementarity tensor eigenvalues are discussed. We formulate tensor eigenvalue complementarity problems as constrained polynomial optimization. When one tensor is strictly copositive, the complementarity eigenvalues can be computed by solving polynomial optimization with normalization by strict copositivity. When no tensor is strictly copositive, we formulate the tensor eigenvalue complementarity problem equivalently as polynomial optimization by a randomization process. The complementarity eigenvalues can be computed sequentially. The formulated polynomial optimization can be solved by Lasserre’s hierarchy of semidefinite relaxations. We show that it has finite convergence for generic tensors. Numerical experiments are presented to show the efficiency of proposed methods.     

A new class of alternative theorems for SOS-convex inequalities and robust optimization

In this paper, we present a new class of alternative theorems for SOS-convex inequality systems without any qualifications. This class of theorems provides an alternative equations in terms of sums of squares to the solvability of the given inequality system. A strong separation theorem for convex sets, described by convex polynomial inequalities, plays a key role in establishing the class of alternative theorems. Consequently, we show that the optimal values of various classes of robust convex optimization problems are equal to the optimal values of related semidefinite programming problems (SDPs) and so, the value of the robust problem can be found by solving a single SDP. The class of problems includes programs with SOS-convex polynomials under data uncertainty in the objective function such as uncertain quadratically constrained quadratic programs. The SOS-convexity is a computationally tractable relaxation of convexity for a real polynomial. We also provide an application of our theorem of the alternative to a multi-objective convex optimization under data uncertainty.     

Zur numerischen Lösung gewöhnlicher Differential-gleichungen mit Splines in einem Sonderfall

In an earlier paper [1] a general procedure has been presented to obtain polynomial spline approximations for the solution of the initial value problem for ordinary differential equations. In this paper the general procedure is described by an equivalent one step method. Furthermore two convergence theorems are proved for a special case which is not included in the general convergence or divergence theory given in [1].     

Methods of solving spatial problems of the mechanics of a deformable solid in terms of stresses

The formulation in /1/ of a quasistatic problem of the mechanics of a deformable solid in terms of stresses is discussed, including also the variational formulation, which consists of solving six equations in six symmetric stress tensor components when six boundary conditions are satisfied. Methods of successive approximation are proposed for solving this problem and theorems on the convergence of these methods, including a “rapidly converging” method, whose rate of convergence is substantially higher than a geometric progression, are proved.     

Linear relations among algebraic solutions of differential equations

For any univariate polynomial with coefficients in a differential field of characteristic zero and any integer, q, there exists an associated nonzero linear ordinary differential equation (LODE) with the following two properties. Each term of the LODE lies in the differential field generated by the rational numbers and the coefficients of the polynomial, and the qth power of each root of the polynomial is a solution of this LODE. This LODE is called a qth power resolvent of the polynomial. We will show how one can get a resolvent for the logarithmic derivative of the roots of a polynomial from the αth power resolvent of the polynomial, where α is an indeterminate that takes the place of q. We will demonstrate some simple relations among the algebraic and differential equations for the roots and their logarithmic derivatives. We will also prove several theorems regarding linear relations of roots of a polynomial over constants or the coefficient field of the polynomial depending upon the (nondifferential) Galois group. Finally, we will use a differential resolvent to solve the Riccati equation.