关于一类临界点在单位圆周的有理函数的存在性及构造
On the Existence and Construction of Rational Functions with Critical Points on the Unit Circle

周宏毅在论文关于Herman环与临界点中给出了三次有理函数且其临界点严格位于Herman环的边界分支的例子。该构造中主要用到临界点都位于单位圆周且保持单位圆周不动的有理函数的存在性。本文给出了一般的有理函数临界点均在单位圆周且保持单位圆周不动的存在性证明。同时讨论了一般显示构造的方法。
In A Note on Herman, Hongyi Zhou gave an example of a cubic rational function whose critical points strictly lie on the boundary of the Herman ring. The construction mainly relies on the existence of rational functions whose critical points are located on the unit circle and keep the unit circle invariant. In this paper, we provide a general proof for the existence of rational functions whose critical points are all on the unit circle and keep the unit circle invariant. Additionally, we discuss the general methods for explicit constructions.