L-space knots with tunnel number >1 by experiment

Abstract

In Dunfield's catalog of the hyperbolic manifolds in the SnapPy census which are complements of L-space knots in $S^3$, we determine that $22$ have tunnel number $2$ while the remaining all have tunnel number $1$. Notably, these $22$ manifolds contain $9$ asymmetric L-space knot complements. Furthermore, using SnapPy and KLO we find presentations of these $22$ knots as closures of positive braids that realize the Morton-Franks-Williams bound on braid index. The smallest of these has genus $12$ and braid index $4$.

This is a significant expansion/rewrite of the original version. The title and abstract have both changed to reflect this. Relevant code is included in the body of the article itself. Originally, this was a note that collected the results of an "office hour" session on the use of SnapPy and KLO held at the ICERM workshop Perspectives on Dehn Surgery, July 15--19, 2019