## Intersection formula and independence for spherical twists from decorated marked surfaces

**报告题目**: Intersection formula and independence for spherical twists from decorated marked surfaces

**报告人**：周宇博士（University of Bielefeld)

**时间**：2014年9月11日（星期四）15:00-16:00

**地点**：理科楼数学系A304

**摘要**: For each triangulation of a decorated marked surface S, there is an associated differential graded algebra whose finite dimensional derived category D is a triangulated 3-Calabi-Yau category. In this talk, we give a bijection between spherical objects in D up to shift and closed curves in S and show that this bijection is independent of the choice of a triangulation of S. Using the compatibility between spherical twists on D and braid twists on S, we prove that the intersection number of two closed curves is equal to the dimension of the graded space of morphisms between the corresponding objects. This is a joint work in progress with Yu Qiu.

**联系人**：朱彬

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