AI中文摘要
Good和Meddaugh证明了每个具有跟踪性的紧致度量动力系统都是有限型转移的逆序列的逆极限的因子。我们首先证明,仅就这一因子表示而言,这两个假设都是不必要的:每个紧致豪斯多夫动力系统都是有限型转移的逆系统的逆极限的因子。特别地,这种符号逆极限表示的存在性并非跟踪性所特有。本文的主要贡献在于识别了度量情形下跟踪性所提供的额外稳定性。我们证明每个具有跟踪性的紧致度量系统都是粘合映射为满射的有限型转移逆序列的逆极限的因子。因此,该逆序列满足Mittag-Leffler条件,并且相应的零维扩张仍具有跟踪性。这加强了Good和Meddaugh的度量表示定理,并完成了他们关于有限型转移的Mittag-Leffler逆序列的ALP因子的刻画。最后,对于任意紧致豪斯多夫空间,我们证明每个紧致跟踪系统共轭于具有因子粘合映射的可度量跟踪系统的逆极限。在此意义上,紧致跟踪系统是由有限型转移通过最多三次应用两个保持跟踪性的操作(取Mittag-Leffler逆极限和过渡到ALP因子)生成的。
英文摘要
Good and Meddaugh proved that every compact metric dynamical system with shadowing is a factor of the inverse limit of an inverse sequence of shifts of finite type. We show first that, for this factor representation alone, both assumptions are unnecessary: every compact Hausdorff dynamical system is a factor of the inverse limit of an inverse system of shifts of finite type. In particular, the mere existence of such a symbolic inverse-limit representation is not specific to shadowing.
The main contribution of the paper is to identify the additional stability which shadowing provides in the metric case. We prove that every compact metric system with shadowing is a factor of the inverse limit of an inverse sequence of shifts of finite type whose bonding maps are surjective. Hence the inverse sequence satisfies the Mittag-Leffler condition, and the corresponding zero-dimensional extension still has shadowing. This strengthens the metric representation theorem of Good and Meddaugh and completes their characterization in terms of ALP factors of Mittag-Leffler inverse sequences of shifts of finite type. Finally, for arbitrary compact Hausdorff spaces, we show that every compact shadowing system is conjugate to the inverse limit of metrizable shadowing systems with factor bonding maps. In this sense, compact shadowing systems are generated from shifts of finite type by applying, at most three times, the two shadowing-preserving operations of taking Mittag-Leffler inverse limits and passing to ALP factors.