Solving the problem of: what is the maximum velocity a spacecraft can travel at such that it can "slingshot" off stars in sequence to arrive at its next destination star?
At each star the spacecraft will enter a hyperbolic orbit, deflecting it by some angle which sets it on a trajectory for the next star. There will be some maximum velocity for this to be possible at each star, but we may use the minimum of these velocities so that each star can be visited with minimal fuel needed for only minor course corrections.