UBC Topology Seminar: Ryan Budney
Topic
Isotopy in dimension 4
Speakers
Details
I will describe why the trivial knot S2-->S4 has non-unique spanning discs up to isotopy. This comes from a chain of deductions that include a description of the low-dimensional homotopy-groups of embeddings of S1 in S1xSn (for n>2), a group structure on the isotopy-classes of reducing discs of S1xDn, and the action of the diffeomorphism group Diff(S1xSn) on the embedding space Emb(S1, S1xSn). Roughly speaking, these results say there is no direct translation from dimension 3 to 4, for the Hatcher-Ivanov theorems on spaces of incompressible surfaces. Or said another way, isotopy in dimension 4 is more closely analogous to isotopy in high dimensions.
Additional Information
Location: ESB 4127 PIMS Video Conference Room
Ryan Budney, University of Victoria
Ryan Budney, University of Victoria
This is a Past Event
Event Type
Scientific, Seminar
Date
February 26, 2020
Time
-
Location