中科院数学与系统科学研究院
数学研究所
动力系统研讨班报告
报告人：Prof. Toshiyuki Sugawa(Tohoku University)
题 目：Hyperbolic geometry of punctured spheres
时 间：2018.08.22（星期三）, 16:00-17:00
地 点：数学院南楼N913室
摘 要：We consider the Riemann surface X obtained by removing n points from the Riemann sphere. It is well known that X has the hyperbolic metric when n is at least three. In this talk, we consider mainly the case when n>3. Our final goal is to construct an explicitly expressed distance function on X which is comparable with the hyperbolic distance on X. To this end, we propose a quantity given in terms of the cross ratios of four points from the punctures to detect locations of collars as well as its width. This is joint work with Tanran Zhang at Soochow University and, partly, with Matti Vuorinen at University of Turku.
