Splitting singular fibers with periodic monodromies into Lefschetz fib…
| 구분 | 박사학위 논문 발표 |
|---|---|
| 일정 | 2025-12-17 16:00 ~ 17:00 |
| 강연자 | 김형기 (서울대) |
| 기타 | |
| 담당교수 | 박종일 |
A Lefschetz fibration is a smooth 4-manifold object admitting surface bundle structure over surface except finite singular fibers, whose singularity is only nodal type.
From the structure of singular fiber, each monodromy of a singular fiber is given by a right handed Dehn twist along a curve, called a vanishing cycle, in the fiber surface.
Collecting all monodromy data from singular fibers, we have a monodromy factorization into right handed Dehn twists, which is the complete information of the Lefschetz fibration.
In my thesis paper, I construct a fibration with one singular fiber which has a periodic monodromy (that is, monodromy homeomorphism is isotopic to a periodic map).
From the idea of Matsumoto, I give a splitting of the singular fiber into Lefschetz fibers and their vanishing cycles for some collection of periodic monodromies.
In this talk, I explain the detailed story of reading vanishing cycles using two branched cover structure of fibers.
