Characterising slopes for hyperbolic knots and Whitehead doubles

Abstract

A slope $p/q\in \mathbb{Q}$ is characterising for a knot $K\subset {\mathbb{S}}^3$ if the oriented homeomorphism type of the manifold ${\mathbb{S}}_K^3(p/q)$ obtained by Dehn surgery of slope $p/q$ on $K$ uniquely determines the knot $K$. We combine analysis of JSJ decompositions with techniques involving lengths of shortest geodesics to find explicit conditions for a slope to be characterising for $K$ in the case where $K$ is any hyperbolic knot or any satellite knot by a hyperbolic pattern. Assuming that the list of 2-cusped orientable hyperbolic 3-manifolds obtained using the computer programme SnapPy is complete up to a certain point, we use hyperbolic volume inequalities to generate a refinement for the special case of Whitehead doubles. We also construct pairs of multiclasped Whitehead doubles of double twist knots for which $1/q$ is a non-characterising slope.

28 pages, 8 figures, 5 tables. Revised title. Accepted for publication in Algebraic & Geometric Topology