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Non-Noether conserved quantity constructed by using form invariance for Birkhoffian system 总被引:6,自引:0,他引:6
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Based on the invariance of Birkhoffian equations under the infinitesimal transformations of groups, the definition and the criterion of a form invariance for a Birkhoffian system are established. The condition under which the form invariance can lead to a non-Noether conserved quantity and the form of the conserved quantity are deduced by relyingon the total time derivative along the trajectory of the equations, and two corollaries in special cases are presented. An example is finally given to illustrate the application of the results. 相似文献
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The oscillation of a delay difference equationis studied and the necessary and sufficient condition for all positive solutions of (E) to oscillate about its positive equilibrium is obtained. 相似文献
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该文对Burgers方程的非古典势对称群进行研究,得到几类非古典势对称群生成元并用其求得Burgers方程的相应特解,这些新特解不能由Burgers方程本身的古典Lie对称与非古典Lie对称来获得。 相似文献
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Some nonclassical potential symmetry generators and group-invariant solutions of heat equation and wave equation were determined. It is shown that some new explicit solutions of partial differential equations in conserved form can be constructed by using the nonclassical potential symmetry generators which are derived from their adjoint system. These explicit solutions cannot be obtained by using the Lie or Lie-Backlund symmetry group generators of differential equations. 相似文献
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提出由Birkhoff系统Noether对称性导出非Noether守恒量的方法.首先,证明系统Noether对称性必然是Lie对称性;其次,将Hojman定理应用于Noether对称性;最后,举例说明结果的应用. 相似文献
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研究非保守Nielsen方程由形式不变性直接导致的非Noether守恒量.函数对时间的全导数采 用沿运动轨道曲线的方式,给出非保守Nielsen方程的非点的形式不变性的定义和判据,并 研究其Noether守恒量.得到形式不变性导致非Noether守恒量的条件以及守恒量的形式,并 给出三种特殊情形的推论.举例说明结果的应用.
关键词:
Nielsen方程
形式不变性
非Noether守恒量 相似文献
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尝试直接从微分方程出发寻找系统守恒量.将微分方程线性化,求得线性化方程的伴随方程.伴随方程的解若同时满足伴随不变条件就可以由之构造出系统的守恒量.该方法不需要系统的Lagrange函数,以电报方程为例加以说明. 相似文献
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By using the concept of almost periodic "sequence", that is, a real valued function on Z satisfying the Bohr almost periodic condition, sufficient conditions are obtained for the existence of almost periodic solutions of Lasota-Wazewska-type differential equations with almost periodic time dependence. 相似文献