A discussion about the smooth Schoenflies' conjecture

Geometry Topology Student Seminar
Wednesday, September 26, 2018 - 2:00pm
1 hour (actually 50 minutes)
Skiles 006
Georgia Tech
The Schoenflies' conjecture proposes the following: An embedding of the n-sphere in the (n+1)-sphere bounds a standard (n+1)-ball. For n=1, this is the well known Jordan curve theorem. Depending on the type of embeddings, one has smooth and topological versions of the conjecture. The topological version was settled in 1960 by Brown. In the smooth setting, the answer is known to be yes for all dimensions other than 4, where apart from one special case, nothing is known. The talk will review the question and attempt to describe some of the techniques that have been used in low dimensions, especially in the special case, that was worked out by Scharlemann in the 1980s. There are interesting connections to the smooth 4-dimensional Poincare conjecture that will be mentioned, time permitting. The talk is aimed to be expository and not technical.