  We apply Bayesian optimization and reinforcement learning to a problem in
topology: the question of when a knot bounds a ribbon disk. This question is
relevant in an approach to disproving the four-dimensional smooth Poincar\'e
conjecture; using our programs, we rule out many potential counterexamples to
the conjecture. We also show that the programs are successful in detecting many
ribbon knots in the range of up to 70 crossings.
