University of Cambridge > Talks.cam > Differential Geometry and Topology Seminar > Slice alternating knots, rational balls, and lattice embeddings

Slice alternating knots, rational balls, and lattice embeddings

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  • UserBrendan Owens (Glasgow)
  • ClockWednesday 17 May 2023, 16:00-17:00
  • HouseMR13.

If you have a question about this talk, please contact Oscar Randal-Williams .

A fundamental problem in smooth 4-dimensional topology is to understand which surfaces in the 4-ball can be bounded by a given classical knot or link, and in particular, whether a given knot is slice (bounds a disk). A related problem is to understand when a given 3-manifold bounds a rational homology 4-ball. I will introduce these problems and then focus on the case of alternating knots and links, and describe some recent work in two directions: 1) the determination of the sliceness of 99.9997% of the over 1.2 billion prime alternating knots with up to 21 crossings, joint with Frank Swenton, and 2) progress towards a conjectured characterisation of when the double branched cover of an alternating link bounds a rational ball, joint with Josh Greene, and using work of Greene and Jabuka. The key tool is Donaldsonโ€™s diagonalisation theorem, augmented with some Heegaard Floer theory.

This talk is part of the Differential Geometry and Topology Seminar series.

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