Section 6.2.2 introduced the vertical cell decomposition to
solve the motion planning problem when
is polygonal. It is
important to understand, however, that this is just one choice among
many for the decomposition. Some of these choices may not be
preferable in 2D; however, they might generalize better to higher
dimensions. Therefore, other cell decompositions are covered in this
section, to provide a smoother transition from vertical cell
decomposition to cylindrical algebraic decomposition in Section
6.4, which solves the motion planning problem in any
dimension for any semi-algebraic model. Along the way, a cylindrical
decomposition will appear in Section 6.3.4 for the special
case of a line-segment robot in
.