Tuesday Seminar on Topology

Seminar information archive ~11/23Next seminarFuture seminars 11/24~

Date, time & place Tuesday 17:00 - 18:30 Room #056 (Graduate School of Math. Sci. Bldg.)
Organizer(s) KOHNO Toshitake, KAWAZUMI Nariya, KITAYAMA Takahiro, SAKASAI Takuya
Remarks Tea: 16:30 - 17:00 Common Room

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2017/11/28

17:00-18:30   Room #056 (Graduate School of Math. Sci. Bldg.)
Sang-hyun Kim (Seoul National University)
Diffeomorphism Groups of One-Manifolds (ENGLISH)
[ Abstract ]
Let a>=2 be a real number and k = [a]. We denote by Diff^a(S^1) the group of C^k diffeomorphisms such that the k--th derivatives are Hölder--continuous of exponent (a - k). For each real number a>=2, we prove that there exists a finitely generated group G < Diff^a(S^1) such that G admits no injective homomorphisms into Diff^b(S^1) for any b>a. This is joint work with Thomas Koberda.