Eri Hatakenaka (Tokyo Institute of Technology)
Title:Invariants of 3-manifolds formulated on their presentations given by 3-fold branched covering spaces over the 3-sphere

---

Abstract:
By a well-known theorem of Hilden and Montesinos, every closed oriented 3-manifold is an irregular 3-fold branched covering of $S^3$ branched along a knot. Piergallini introduced covering moves, which relates such branch sets representing the same 3-manifold. Hence we can regard the branch set as a presentation of the 3-manifold. We give new invariants of 3-manifolds using this presentation. Then we construct the Dijkgraaf-Witten invariant as an example of the invariants.