Colloquium
Title: Rotational symmetries of knots
Speaker: Swatee Naik, University of Nevada and NSF
Abstract: Knots are circles embedded in the three dimensional sphere. Periodic knots, such as the overhand or trefoil knot, are invariant under a rotation, and this symmetry can be easily illustrated in a knot diagram drawn in the plane. It so happens that the orbit space is also a three-sphere, in which the image of a periodic knot is called a quotient knot. Many properties of periodic knots are a direct consequence of the branched covering set up that occurs between various three-manifolds that are naturally associated with the periodic knot and the quotient knot, respectively.
In this talk we will begin with definitions and examples, introduce the basics of the theory, and demonstrate how properties of periodic knots can be used to detect knots that are not periodic. Our tools will include knot polynomials, homology of branched covers, and Heegaard-Floer correction terms.