What is a good bijection? A case study on pattern-avoiding permutations

报告题目：What is a good bijection? A case study on pattern-avoiding permutations

报告人：Sergey Kitaev (University of Strathclyde)

摘要：A bijection is a one-to-one correspondence between two sets. Usually, there is more than one way to build a bijection between equinumerous sets (and there are of course many if the sets aren't very small and we don't care whether the bijections are intelligible). What is a good bijection between two sets? Is it one that is easy to describe? Or, is it one that better illuminates structural similarity between the sets in question? Even though the answer “it depends” is acceptable here, much more can be said under certain assumptions in certain situations. I will illustrate this idea by going through a remarkable story of a problem in the theory of permutation patterns.

时间：3月31日（星期一），15:00-16:00

地点：明德楼B201-1