Title : Pseudo-Anosov braids on the $2$-sphere
(a joint work with K. Ichihara and K. Motegi)
Speaker : Eiko Kin (Kyoto University)
Abstract :

We consider homeomorphisms of $2$-$d$ disk or $2$-$d$ sphere. Periodic orbits for such maps give geometric braids on the disk/sphere, and these braids are classified into three types; periodic, reducible, pseudo-Anosov type. (These are called Nielsen-Thurston types.) Geometric braids on the disk naturally induce those on the sphere. We will discuss the Nielsen-Thurston types of braids on the sphere induced from braids of pseudo-Anosov type on the disk. This is joint work with K. Ichihara and K. Motegi.

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