报告人：郑锡忠 教授 （Arcadia大学）
时间：2010年6月9日(周三)上午10:00-11:00
地点：闵行校区数学楼126室
题目：Computability and Complexity in Analysis
（分析中的可计算性和计算复杂性）

摘要：The notion of computable real numbers was introduced by Alan Turing in his seminal paper of 1936. To define the computability of real numbers precisely, he developed the famous computation model --- the Turing machines. Although the computability theory mainly concerns the discrete sets in the last 70 years, a computability theory of real numbers is of great interests for theoretical research as well as for practical applications. This talk will give a short overview about the recent development of this theory. Several variants of computability of real numbers will be introduced. We explore their mathematical properties and computability theoretical properties as well. Especially, we will show a finite hierarchy of computable approximable real numbers which corresponds different requirements of computability in applications.