For the algorithms in Chapter 5, resolution completeness and probabilistic completeness rely on having a sampling sequence that is dense on . In the present setting, this would require dense sampling on . Differential constraints, however, substantially complicate the sampling process. It is generally not reasonable to prescribe precise samples in that must be reached because reaching them may be impossible or require solving a BVP. Since paths in are obtained indirectly via action trajectories, completeness analysis begins with considering which points can be reached by integrating action trajectories.