共查询到20条相似文献,搜索用时 46 毫秒
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本文考虑Lienard方程x“+f(x)x‘+g(x)=e(t),我们得到:当-∞<infg‘(x)≤supg‘(x)&;lt;0且sups∈R|f(x)|&;lt;+∈∞时,对于任意周期或概周期函数e(t),它有周期或概周期解,而对于Lienard方程x“+f(x)x‘+cx=e(t),我们得到:当c&;gt;0且0&;lt;inf|f(x)|≤supx∈R|F(X)|&;lt;+∞时,对于任意周期或概周期函数e(t),它有周期或周期解。 相似文献
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我们研究初始值问题(e)u1/(e)t2=(e)2u1/(e)x2+‖u2(·,t)‖p,
(e)2u2/(e)t2=(e)2u2/(e)x2+‖u1(·,t)‖q,-∞<x<∞,t>0,u1(x,0)=f1(x),
(e)u1/(e)t(x,0)=g1(x),u2(x,0)=f2(x), (e)u2/(e)t(x,0)=g2(x),- ∞<x<∞,where‖ui(·,t)‖=∫∞-∞(4)i(x)|ui(x,t)|dx
with (4)i(x)≥0 and ∫∞-∞(4)i(x)dx=1,i=1,2.然后建立解的全局存在和爆破的标准,提出爆破增长率. 相似文献
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设f(z)是把|z|<1映成|w|<1的K-Q.C.,f(0)=0,则有准确不等式... 相似文献
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本文主要证明了如下结果: 设ρ级整函数f(x)具有k(1≤k<+∞)个判别有穷渐近值。如果k=2ρ,则有 1) f(z)不能有有穷亏值, 2) 对任意值θ,0≤θ<2π,或者半直线argz=θ是f(x)的一条Julia方向,或者有... 相似文献
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本文主要论证了亏值、渐近值和茹利雅方向三者之间的关系,得到下述结果: 1.设f(z)是下级μ为有穷的整函数.记f(z)的茹利雅方向个数为q,有穷判别渐近值个数为l,有穷亏值个数为p,其中l′个亏值同时是渐近值,则有关系式 2p-l′+l≤q. 如果进一步假设 2p-l′+l=q<+∞,则有p=l′和λ=μ,其中λ是f(z)的级. 2.设w=f(z)是下级μ为有穷的亚纯函数.记f(z)的茹利雅方向个数为q,f(z)的反函数z=g(w)的判别直接超越奇点个数为l,f(z)的亏值个数为p,其中l′个亏值同时是g(w)的直接超越奇点,则有关系式 p-l′+l≤g. 如果进一步假设 p-l′+l=q<+∞,以及0<μ≤λ<+∞,其中λ是f(z)的级,则f(z)的每个亏值同时是渐近值. 相似文献
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设w=f(z)是把|z|<1映成|w|<1的K-Q.C.,f(0)=0。 关于w=f(z)的像的交点中,距原点最远点记为w_k,1≤k≤n记,并研究极值问题: 获得以下两个准确估值: 与,式中的φn是Grzsch函数φ(p)(p>1)的n次对称形式:设w=f(x)是把|z|<1映成|w|<1且保持原点不动的K-拟共形映照(K-Q.C.).有熟知的估值 式中的(P)(P>1)是Grtzsch的区域函数.运用这个函数的渐近性质,可以获得极值问题的准确解.本文目的在于把这个问题精致化,获得一个广泛而精确的结果. 相似文献
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设 f(z)为下级μ<+∞的平面内的亚纯函数,argz=θk(k=1,2,…,m;1≤m <+∞;0≤θ1<θ2<…<θm<2π,θm+1=θ1+2π为平面内m条射线,使得对任意的ε>0及X=0,∞有 这里ρ为一任意给定的非负实数.如果f(1)(z)(l≥0)具有一个有穷非零亏值 a,则f(z)的级λ≥max(π/ωρ)其中ω=min (θk+1-θk). 相似文献
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Wu Shengjian 《数学年刊B辑(英文版)》1994,15(4):453-462
Suppose that f(z)is a meromorphic function of order λ(0<λ<+∞)and of lower order μ in the plane.Let ρ be a positive number such that μ≤ρ≤λ.(1)If f^(l)(z)(0≤l<+∞)has p(1≤p<+∞)finite nonzero deficient valnes αi(i=1,…,p)with deficiencies δ(αi,f^(l)),then f(z)has a (0,∞)accumulative line of order ≥ρin any angular domain whose vertex is at the origin and whose magnitude is larger than max(π/ρ,2π-4/ρ ∑i=1^p arcsin √δ(αi,f^(l))/2).(2)If f(z) has only p(0<p<+∞)(0,∞),accumulative lines of order≥ρ:arg z=θk(0≤θ1<θ2<…<θp<2π,θp+1=θ1+2π),then λ≤π/ω,where ω=min I≤k≤p(θk+1-θk),provided that f^(l)(z)(0≤l<+∞)has a finite nonzero deficient value. 相似文献
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本文证明了以下结果:设f(x)是开平面|x|<+∞上下级为μ的整函数,它的零点分布在始自原点的q条半直线上.记f(x)的有穷判别渐近值个数为l,非零有穷亏值个数为P,其中l′个亏值同时是渐近值,如果q<+∞,则有P—l′+l≤2μ。 相似文献
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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... 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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S. V. Kerov 《Journal of Mathematical Sciences》1988,41(2):995-999
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. 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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Vladimir I. Arnold 《Functional Analysis and Other Mathematics》2009,2(2-4):151-164
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. 相似文献