arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1002.0901nlin.SI
收藏

一类新的可积二阶非线性微分方程及其与二维Lotka-Volterra系统的联系

On certain new integrable second order nonlinear differential equations and their connection with two dimensional Lotka-Volterra system

R. Gladwin Pradeep, V. K. Chandrasekar, M. Senthilvelan, M. Lakshmanan

摘要:

本文考虑二阶非线性常微分方程$\ddot{x}+k_1\frac{\dot{x}^2}{x}+(k_2+k_3x)\dot{x}+k_4x^3+k_5x^2+k_6x=0$,其中$k_i$,$i=1,2,...,6,$是任意参数.利用改进的Prelle-Singer方法,在已知的$k_2=0, k_3=0$和$k_1=0, k_2=0, k_5=0$两种可积情形之外,我们还发现了五种新的可积情形.在这五个方程中,四个方程允许时间相关的首次积分,其余一个允许时间无关的首次积分。从与时间无关的首次积分出发,导出了非标准哈密顿量的结构,从而证明了可积性的刘维尔意义。在含时积分的情况下,我们要么显式积分系统或转换到一个时间无关的情况下,推导出底层的哈密顿结构。我们还证明了上述二阶常微分方程与二维Lotka-Volterra(LV)系统密切相关。由上述非线性方程的可积参数,可以导出后者的所有已知可积情形。

英文摘要:

In this paper, we consider a second order nonlinear ordinary differential equation of the form $\ddot{x}+k_1\frac{\dot{x}^2}{x}+(k_2+k_3x)\dot{x}+k_4x^3+k_5x^2+k_6x=0$, where $k_i$'s, $i=1,2,...,6,$ are arbitrary parameters. By using the modified Prelle-Singer procedure, we identify five new integrable cases in this equation besides two known integrable cases, namely (i) $k_2=0, k_3=0$ and (ii) $k_1=0, k_2=0, k_5=0$. Among these five, four equations admit time dependent first integrals and the remaining one admits time independent first integral. From the time independent first integral, nonstandard Hamiltonian structure is deduced thereby proving the Liouville sense of integrability. In the case of time dependent integrals, we either explicitly integrate the system or transform to a time-independent case and deduce the underlying Hamiltonian structure. We also demonstrate that the above second order ordinary differential equation is intimately related to the two-dimensional Lotka-Volterra (LV) system. From the integrable parameters of above nonlinear equation and all the known integrable cases of the latter can be deduced thereby.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑