特征列

This dissertation is changed into two parts. The first part, the theory and application about Wu-Ritt differential characteristic sequence method are discussed, which involves the theories of differential equations, abstract algebra and computer algebra etc.

本文共分两部分，第一部分讨论微分特征列法的理论和应用问题，涉及到微分方程，抽象代数，计算机代数等重要学科。

Differential characteristic set method ofdifferential polynomial system is used to overcome the huge difficulties in calculation.

在本文的计算过程中，用Mathematica软件编写的求解微分特征列集的程序包克服了现有计算方法中的一些困难，在很大程度上减少了本文的计算量。

Also underCoherent conditions a algorithm of differential Characteristic set for differential polynomial systemis given.

给出了Coherent条件下的特征列集的算法。

The differential characteristic set for differential polynomial system maintains the essential character of original differential polynomial system.

微分多项式系统的微分特征列集保留了原微分多项式组的本质特征，具有三角化良序结构等优点，能够克服不同领域问题中的一些困难。

Here, differential characteristic set package plays an important role in the calculation.

在计算过程中，采用微分形式的吴方法，微分特征列的程序包起到了重要作用。

Finally, we put forward the concept of differential characteristic set modulo with respect to a polynomial and present the properties of the characteristic set.

最后，对微分特征列集理论进行了推广，给出了微分多项式系统的模微分特征列集的概念，并研究了其具有的性质。

In chapter 1, as a preparative knowledge, the main results about symmetry theoryand Wus method are introduced, in addition some fundamental definitions, such as trans-formation group, infinitesimal operator, prolongation, first integral, infinitesimal criterionfbr invariance of an ODE, characteristic set are recalled.

第一章中作为预备知识简单介绍了对称理论和吴方法，并给出了一些基本概念和理论，如变换群、无穷小算子、算子延拓、首次积分、微分方程在对称下不变的判别准则和微分特征列集算法。

We calculate the differential characteristic set of determining equations for source evolution equations (include several linear and nonlinear differential system of equations).

用算法′计算了几个微分方程对称的确定方程组(包括线性微分方程组以及非线性微分方程组)的微分特征列集，并在计算量上对算法′与算法进行了比较。

In this paper, according toinfinitesimal criterion in symmetry theorem, using differential Wu-method(char-set byMathematica software) and conditions of symmeties of equation u_=Hu_,we givenew potential symmetries for nonlinear telegraph equation u_=F

本文根据对称理论中的无穷小准则，利用微分形式的吴方法(借助于Mathernatica软件编写的求解微分特征列集的程序包)和u_=Hu_型方程对称的存在条件，得到了非线性电报方程u_=F

Char-set has triangular form structure,which is used to overcome some difficulties in differential fields problems.

本文中，我们研究微分情形吴方法，重点研究的是微分多项式系统的微分特征列集的算法及其应用。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。