时间：2025年4月3日（星期四）13:00-17:00
地点：西湖大学云谷校区E4-233
主讲人：Nanjun Yang, BIMSA
报告题目：Witt group of nondyadic curves
报告摘要：The Witt group of an algebraic variety is the Grothendieck group of vector bundles with non-dengenerate symmetric inner products modulo those with Langrangians. It has been studied by Knebusch in 1970s for real algebraic curves. Over local fields, it naturally relates to 2-dimensional class field theory. Only the case of hyperelliptic curves was considered by Parimala, Arason et. al..
In this talk, we compute explicitly the Witt group of smooth projective curves over nondyadic local fields by reduction, which involves the rationality of Theta characteristics. The case of elliptic curves will be given as an example.
