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Some Remarks on Burton's Asymptotic Stable Theorem (in English) |
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Citation: |
Lin Xiaobiao.Some Remarks on Burton's Asymptotic Stable Theorem (in English)[J].Chinese Annals of Mathematics B,1982,3(2):147~152 |
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Authors: |
Lin Xiaobiao; |
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Abstract: |
讨论泛函微分方程$\[\dot x = f(t,{x_t})\]$的解的渐近稳定性理论,往往需要假定f的某种全连续性.Burton在他的论文中讨论了f是一般$\[R \times C \to {R^n}\]$的连续泛函的情况.本文的目的是改进Burton的工作.证明方法釆取更简单的直接证法,证明结果不但同样获得有关解的一致渐近稳定性的结论,而且得到一个有趣的不等式,从中能够导出解的收敛于0的估计式.
设f是$\[R \times C \to {R^n}\]$连续泛函.$$是严格上升的连续函数,$$.设u,v,w是单调不减的连续函数u(0)=v(0)=w(0)=0,且对s>0有u(s),v(s),w(s)>0,
又设$\[|\phi {|_\eta } = \eta (|\phi (0)|) + \frac{1}{r}\int_{ - r}^0 {\eta (|\phi (\theta )|)d} \theta \]$,$\[{w_1}(s) = w({\eta ^{ - 1}}(s))\]$,$\[h(s) = \int_0^s {{w_1}(s)ds} \]$,$\[k(s) = v(s) + \frac{{{w_1}(1)}}{2}rs\]$,那么有如下定理:
定理1 设$\[V:R \times C \to R\]$是连续泛函,使得
$\[u(|\phi (0)|) \le V(t,\phi ) \le v(||\phi |{|_\eta })\]$
$\[V(t,\phi ) \le - w(|\phi (0)|)\]$
那么必有另一个连续泛函$\[G:R \times C \to R\]$,使得对$
\[\eta (|\mu |) < 1\]$有
$\[G(t,\phi ) \le - g(G(t,\phi )),V(t,\phi ) \le G(t,\phi )\]$,
其中$\[g:{R^ + } \to {R^ + }\]$定义为$\[g(s) = h(\frac{1}{2}{k^{ - 1}}(s))\]$
定理2 设定理1的条件均满足,设$\[F(y) = \int_1^y {\frac{{dz}}{{g(z)}}} \]$,那么存在s>0使得对于$\[|{\phi _0}| < s\]$有
$\[|x(t;{t_0},{\phi _0})| \le {u^{ - 1}}({F^{ - 1}}(F(G({t_0},{\phi _0})) + {t_0} - t))\]$
且x=0—致渐近稳定
文章最后给出两个实例说明以上定理的应用. |
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