异常情况时的Liapunov-Kozlov法

Kozlov将Liapunov第一方法推广到非线性力学系统,用来研究保守力和耗散力场中,运动力学系统平衡位置的不稳定性.在平衡位置分析惯性张量的异常,或者Rayleigh耗散函数系数矩阵的异常.在稳定性分析中,实际上不可能应用Liapunov逼近法,因为平衡位置的存在条件,和运动微分方程解的唯一性条件,均无法得到满足.Kozlov的广义Liapunov第一方法,不仅适用上面提及的条件,此外,还知道同样的代数表达式得到满足.给出了3个关于平衡位置的不稳定性定理.用一个例子,举例说明了得到的结果.     

一类非完整系统的Lagrange定理及其应用

本文研究一类非完整系统平衡位置流形的稳定性问题·利用Ляпунов直接法和稳定性定义将完整系统的Ｌａｇｒａｎｇｅ定理推广到一类非完整保守系统与耗散系统，并对该类非完整系统平衡位置流形的渐近稳定性与耗散力间的关系作了新的表述，最后举例说明定理的应用·     

哈密顿-雅可比方法对非线性非完整系统的适用性

本文用庞加莱(Poincaré)形式将哈密顿-雅可比方法(Hamilton-Jacobi method)推广到具有非线性非完整约束的动力系统的运动情况.研究了本方法对该系统推广的必要条件和充分条件.并用非完整系统的某些具体实例进行了说明.     

变质量非线性非完整系统的Gibbs-Appell方程

本文首先将Gibbs-Appell方程推广到最一般的变质量非完整系统.得到变质量非线性非完整系统在广义坐标、准坐标下的Gibbs-Appell方程和积分变分原理,最后给出一个例子.     

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.     

非完整非保守动力学系统的Noether定理及其逆定理

本文应用变换群G_r的无限小群变换的广义准对称性,给出了受一阶非线性非完整约束的非保守动力学系统的Noether定理及其逆定理.     

b-距离空间中有限个等式约束下的耦合不动点问题

本文研究了b-距离空间中有限个等式约束下的耦合不动点问题.利用数学归纳法,获得了b-距离空间中一类有限个等式约束下的非线性压缩耦合不动点结果,将已有的Banach空间中的结果推广到b-距离空间中.特别地,我们结果中的压缩条件与空间系数无关.作为应用,得到了对称等式约束下的不动点定理,公共耦合不动点定理以及b-距离空间中非线性压缩不动点定理.这些结果可以推出许多已有结果,甚至将一些结果中的部分条件完全去掉.     

关于非线性系统的非常稳定性及其应用

本文将C.V.Pao研究Liapunov稳定性的内积法改进、推广和发展,研究了非线性系统的非常稳定性、平衡位置的存在唯一性和Liapunov稳定性.将主要结果直接应用到非线性周期系统的稳态振荡的判定.     

非完整系统有耗散和循环力时的平衡不稳定性

讨论定常非完整系统在耗散、保守、循环力作用下的不稳定平衡问题．应用方法是基于运动微分方程解的存在性,当t→-∞时,系统渐近地趋于平衡状态．假定在平衡位置附近,动能、Reyleigh耗散函数、位置力都是无限可微函数．结果将通过一个实例说明．部分结果参见Kozlov V V. On the asymptotic motions of systems with dissipation. Prikl Math Mekh, 1994, 58(4): 31-36. (in Russian); Merkin D R. Introduction to the Theory of the Stability of Motion. Moscow: Nauka, 1987. (in Russian); Thomson W, Tait P. Treatise on Natural Philosophy, Part Ⅰ. Cambridge: Cambridge University Press, 1879．     

非线性非完整系统Vacco动力学方程的积分方法*

本文给出积分非线性非完整系统Vacco动力学方程的积分方法.首先,将Vacco动力学方程表示为正则形式和场方程形式;然后,分别用梯度法,单分量法和场方法积分相应完整系统的动力学方程,并加上非完整约束对初条件的限制而得到非线性非完整系统Vacco动力学方程的解.     

Study of the blow-up of solutions of systems of equations of hydrodynamic type

Mathematical Notes - We study the initial boundary-value problem for three-dimensional systems of equations of pseudoparabolic type. The system is similar to the Oskolkov system, but differs from...     

Distribution of types of symmetry of tensors of high degree

The asymptotic distribution of tensors of degree N in symmetry types is studied in this paper.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 155, pp. 181–186, 1986.     

Characterization of types of asymptotic discernibility of families of hypotheses

We give a characterization of the types of asymptotic discernibility of families of hypotheses in the case of hypothetical measures that are not, in general, mutually absolutely continuous. The case when the logarithm of the likelihood ratio admits an asymptotic expansion of the type of an expansion with local asymptotic normality is examined in detail. Examples are studied.Translated fromTeoriya Sluchainykh Protsessov, Vol. 15, pp. 64–71, 1987.     

Axiomatizability of reducts of algebras of relations

In this paper, we prove that any subreduct of the class of representable relation algebras whose similarity type includes intersection, relation composition and converse is a non-finitely axiomatizable quasivariety and that its equational theory is not finitely based. We show the same result for subreducts of the class of representable cylindric algebras of dimension at least three whose similarity types include intersection and cylindrifications. A similar result is proved for subreducts of the class of representable sequential algebras. Received October 7, 1998; accepted in final form September 10, 1999.     

Lengths of periods of continued fractions of square roots of integers

Empirical study of the period’s length T of the continued fractions of $\sqrt{Q}$ (for growing integers Q) shows several strange asymptotical results, for instance, $T\leq C\sqrt{Q}\ln{Q}$ . These results show important differences between the statistics of the elements of the continued fractions of random real numbers and of square roots of random integers.