In this paper we are concerned with the existence of invariant curves of planar twist mappings which are almost periodic in a spatial variable. As an application of this result to differential equations we will prove the existence of almost periodic solutions and the boundedness of all solutions for superlinear Duffing’s equation with an almost periodic external force.

中文翻译：

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几乎周期性扭曲映射的不变曲线

在本文中，我们关注平面扭曲映射的不变曲线的存在性，这些曲线在空间变量中几乎是周期性的。作为该结果在微分方程中的应用，我们将证明具有几乎周期性外力的超线性 Duffing 方程的几乎周期解的存在性和所有解的有界性。