Boundary Slope Diameter and Crossing Number of 2-Bridge Knots

In joint work with Maybrun and Robinson, we prove that for 2-bridge knots, the diameter of the set of boundary slopes is twice the crossing number. We also show that 2-bridge knots with four or fewer boundary slopes have a boundary slope of genus two or less. After some topological preliminaries, the argument quickly becomes combinatorial and is based on comparing various continued fraction representations of the same fraction.