共查询到20条相似文献,搜索用时 109 毫秒
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研究了一类三次Kolmogorov捕食者-食饵种群差分系统正周期解的存在性,利用重合度理论中的连续性定理建立了存在正周期解的充分性依据,推广并改进了文献中的相关结果. 相似文献
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该文研究一类变指数二阶差分系统周期解的存在性.当非线性项超线性增长时,运用临界点理论中的环绕定理获得了非平凡周期解存在的充分条件. 相似文献
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平衡点在研究差分系统的零解的稳定性时具有极其重要的作用.本文首先给出了线性差分系统平衡点存在的充要条件,然后给出非线性差分系统平衡点存在的充分条件,最后给出了高阶差分系统平衡点存在的充分条件. 相似文献
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反周期解问题是非线性微分系统动力学的重要特征.近年来,非线性整数阶微分系统的反周期解问题得到了广泛的研究,非线性分数阶微分系统的反周期解问题也得到了初步的讨论.不同于已有的工作,该文研究时不变分数阶系统反周期解的存在性问题.证明了时不变分数阶系统在有限时间区间内不存在反周期解,而当分数阶导数的下限趋近于无穷大时,时不变分数阶系统却存在反周期解. 相似文献
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一类时滞神经网络差分系统周期解的吸引性 总被引:1,自引:0,他引:1
考虑一类 Mc Culloch- Pitts型信号函数的时滞神经网络差分系统周期解的吸引性 ,所得结果改进了文献 [6 ]相关结论。 相似文献
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Yu. N. Lin'kov 《Journal of Mathematical Sciences》1991,53(4):409-415
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. 相似文献
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M. B. Ezhov 《Ukrainian Mathematical Journal》1990,42(7):893-896
This article is devoted to the construction of normal bases of rings of integral elements of certain fields of algebraic functions. These fields are algebraic extensions of the initial fields, given by appropriate algebraic equations. The extensions are given only by the monodromy group. The device of the matrix Riemann boundary-value problem on a Riemann surface is used.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 42, No. 7, pp. 1004–1007, July, 1990. 相似文献
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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. 相似文献
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Yu. S. Urzhumtsev 《Mechanics of Composite Materials》1973,9(3):349-352
A variant of a statistical probability interpretation of elementary micromechanisms of formation of viscoelastic deformations of polymers is examined with the aid of the concept of dissymmetric media and the dissymmetry coefficient. A new rheological relationship is obtained, a particular case of which is the known equation of a typical linear viscoelastic body. A method is given for determining the relaxation spectrum for different intensity functions figuring in the rheological relationships. The results of the calculation are compared with the experimental data, exemplified by the creep of polyamide P-68.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, Vol. 9, No. 3, pp. 392–396, May–June, 1973. 相似文献
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A. V. Berdakchiev 《Mechanics of Composite Materials》1976,12(3):347-352
It is shown that the asymptotic solution of a problem of the nonlinear theory of thermoviscoelasticity, if it exists, can be found directly from the solution of the asymptotic boundary-value problem without completely solving the starting problem.M. V. Lomonosov Moscow State University. Translated from Mekhanika Polimerov, No. 3, pp. 395–400, May–June, 1976. 相似文献
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S.V. Morgunov 《Journal of Applied Mathematics and Mechanics》2012,76(2):250-252
Linear elastic systems with a finite number of degrees of freedom, the initial equations of motion of which are constructed using the finite element method or other discretization methods, are considered. Since, in applied dynamics problems, the motions are usually investigated in a frequency range with an upper bound, the degrees of freedom of the initial system of equations are split into dynamic and quasi-dynamic degrees. Finally, the initial system of equations is split into a small number of differential equations for the dynamic degrees of freedom and into a system of algebraic equations for determining the quasi-static displacements, represented in the form of a matrix series. The number of terms of the series taken into account depends on the accuracy required. 相似文献
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A. P. Ushakova 《Journal of Mathematical Sciences》1998,89(5):1582-1589
An estimate of stability of characterization of distribution types is obtained for the case of additive types. Under some
conditions, the estimate has the order ε1/3L(ε), where L(ε) is a slowly varying function.
Proceedings of the Seminar on Stability Problems for Stochastic Models, Moscow, Russia, 1996, Part I. 相似文献
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Yu. A. Drozd 《Mathematical Notes》1971,10(1):463-465
The investigation of integral representations of arbitrary rings is shown to be equivalent to the case of orders in semisimple algebras. An example is constructed showing that, for an order in a nonsemisimple algebra, the number of representations in the genus may increase without limit with varying genera.Translated from Matematicheskie Zametki, Vol. 10, No. 1, pp. 63–87, July, 1971. 相似文献
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In [2] it was shown with reference to the cylindrical bending of a plate that the Kirchhoff-Love hypothesis is asympototically accurate for determining the critical load irrespective of the properties of the material. However, the question of the dependence of the critical load on the material properties was left unexplored. This question is now numerically investigated. Curves characterizing the variation of the critical load with relative shear modulus are presented.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, Vol. 5, No. 2, pp. 355–357. March–April, 1969. 相似文献
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We investigate properties of dynamical systems associated with the approximation of pseudotrajectories of a dynamical system
by its trajectories. According to modern terminology, a property of this sort is called the “property of tracing pseudotrajectories”
(also known in the English literature as the “shadowing property”). We prove that dynamical systems given by mappings of a
compact set into itself and possessing this property are systems with stable prolongation of orbits. We construct examples
of mappings of an interval into itself that prove that the inverse statement is not true, i.e., that dynamical systems with
stable prolongation of orbits may not possess the property of tracing pseudotrajectories.
Institute of Mathematics, Ukrainian Academy of Sciences, Kiev. Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 49,
No. 8, pp. 1016–1024, August, 1997. 相似文献