Relative completions of mapping class groups

主讲人 Speaker:罗马
时间 Time: 2:00-3:00 pm,2021-11-3
地点 Venue:Zoom Meeting ID:849 963 1368 Passcode:YMSC

摘要 Abstract

I will discuss structures for relative completions of mapping class groups. In higher genus (genus at least 3) cases, presentations are known, and will be reviewed first. The only unknown case is in genus two, where I am jointly working with Tatsunari Watanabe. In this case, the generators are related to Collino cycles. This is similar in higher genus cases where generators are related to Ceresa cycles. Moreover in our case, we provide evidence to generate relations via arithmetic considerations, while in higher genus cases, relations are quite topological.

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