Proof of Field D*'s Case Separation for Arbitrary Simplices

In their development of the Field D* algorithm, Ferguson et. al. prove that a path through a unit length right-angled triangle originating from an interpolated edge, and travelling to the opposite vertex must either be a direct or indirect case. A combination of the two is not optimal. Later work, proves this for arbitrary, but non-degenerate triangles. In this technical report, we prove the same for non-degenerate simplices, which are generalisations of triangles to higher dimensions