首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
汪宏喜 《工科数学》2001,17(1):42-46
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   

2.
邓铿 《应用数学》2005,18(2):181-187
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   

3.
本文主要证明了定理1.设f(x)在开平面|z|<+∞上亚纯,具有一个非零有穷亏值,再设△(θk)(k=1,2,…,q,0≤θ12<…<θq1+2π=θq+1)是q(1≤q<+∞)条半直线,并且对任意给定的数ε,0<ε<π/2,有如果f(z)的下级μ<+∞,则f(z)的级λ≤π/ω<+∞,其中...  相似文献   

4.
何成奇 《中国科学A辑》1987,30(2):113-125
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   

5.
张广厚 《中国科学A辑》1982,25(11):983-994
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   

6.
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   

7.
何成奇 《中国科学A辑》1983,26(11):967-974
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Grtzsch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   

8.
伍胜健 《中国科学A辑》1993,36(6):565-575
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≤θ12<…<θm<2π,θm+11+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+1k).  相似文献   

9.
DISTRIBUTION OF THE(0,∞)ACCUMULATIVE LINES OF MEROMORPHIC FUNCTIONS   总被引:1,自引:0,他引:1  
Suppose that f(z)is a meromorphic function of order λ(0&lt;λ&lt;+∞)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&lt;+∞)has p(1≤p&lt;+∞)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&lt;p&lt;+∞)(0,∞),accumulative lines of order≥ρ:arg z=θk(0≤θ1&lt;θ2&lt;…&lt;θp&lt;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&lt;+∞)has a finite nonzero deficient value.  相似文献   

10.
张广厚 《中国科学A辑》1986,29(10):1009-1022
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   

11.
Yushkov  E. V. 《Mathematical Notes》2011,90(3-4):597-610
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   

12.
13.
14.
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   

15.
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   

16.
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   

17.
杨海宣 《数学学报》1998,41(4):727-730
本文研究了完全正则半群簇的子簇格[V+∩PV,V+∩PV]的某些格运算性质,我们证明了簇V+∩PV可分解为V与V+∩PV的并;对任意完全正则半群簇W,有W∩(V∨V+∩PV)=(W∩V)∨(W∩V+∩PV).特别地,我们得到了等式V+∩PV=V成立的若干条件.  相似文献   

18.
19.
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   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号