1. This is often regarded as 2-D (horizontal and vertical). This approach has been adopted in the earlier chapters of this book.
2. A function is said to be bijective, if it relates each member of a set S (the domain) to a separate and distinct member in T (the range), where each member in T also has a corresponding member in S.
3. A fax-film is an imprint of the surface obtained by dissolving a sheet of acetate with acetone and letting it harden.
4. 3-D data from most surfaces can be summarized through a fairly well established set of parameters described in Chapter 1 and Stout et al (1993). However, if special kinds of surfaces such as honed cylinder bores are to be characterized, problem-specific parameters such as those presented in this chapter offer the best solution.