The visualization of the diff area taxonomy between the ontology excerpts in Figure 3(a) and Figure 4. The diff areas are organized into color coded levels according to the number of their object properties. The level numbers appear at the left edge of the figure. Diff areas are shown with differed colored borders to indicate the type of diff area. Modified areas, introduced areas, and removed areas are drawn with a yellow border, green border, and red border, respectively. Unmodified areas are shown with no border. Child-of links are colored red, green, or black if they were removed, introduced, or unmodified, respectively. (Child-of links cannot be modified.)