In the fourth and fifth chapters of this paper , we discuss the schwarzian derivatives of analytic functions , the nehari families and the extremal set of schwarzian derivatives , and apply the obtained results to determine the inner radius of univalence of rectangles and hexagons with equal angles 在第四章和第五章中，对解析函数的schwarz导数和nehari族以及schwarz导数的极值集作了深入细致的研究，并且利用所得到的结果研究了矩形、等角六边形的单叶性内径问题。
