Tuesday Seminar on Topology

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Date, time & place Tuesday 16:00 - 17:30 056Room #056 (Graduate School of Math. Sci. Bldg.)
Organizer(s) IKE Yuichi, KONNO Hokuto, SAKASAI Takuya

2014/07/08

16:30-18:00   Room #056 (Graduate School of Math. Sci. Bldg.)
Ingrid Irmer (JSPS, the University of Tokyo)
The Johnson homomorphism and a family of curve graphs (ENGLISH)
[ Abstract ]
Abstract: A family of curve graphs of an oriented surface $S_{g,1}$ will be defined on which there exists a natural orientation, coming from the orientation of subsurfaces. Distances in these graphs represent commutator lengths in $\\pi_{1}(S_{g,1})$. The displacement of vertices in the graphs under the action of the Torelli group is used to give a combinatorial description of the Johnson homomorphism."