Let us consider Fig. 1. In Fig. 1, there are four regions, as indicated (R4 9 epresents the entire space not occupied by the graph). Suppose we are given all of he edges of the graph and their geometrical orientation. Can we find all of the 'egions automatically? A similar problem was discussed in [Nie 82]. In their )roblem, we are given a polygon which is not simple and we are asked to produce...
