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Branch Coverings, Tangles, and Dehn Surgery
Student-Run Geometry/Topology Seminar| Speaker: | Mike Williams, Davis |
| Location: | 693 Kerr |
| Start time: | Thu, Oct 6 2005, 12:40PM |
Branch Coverings, Tangles, and Dehn Surgery Abstract: I will discuss how double branch coverings arise in the study of Dehn surgery on strongly invertible knots in the 3-sphere. A classical result of J.Montesinos (refined by S.Bleiler) is that the surgery 3-manifold double branch covers the 3-sphere and the branch set (downstairs) has a projection obtained by an "untangle surgery" on a projection of the unknot. This has proved to be effective for studying, in particular, lens space surgeries.