In this course we will identify a series of prototypic problems (prototypes). To each of these prototypes we associate a related group of problems which we call the aura of that prototype. We shall discover that, although we always solve the prototype in class, the other problems in the aura can rapidly become quite difficult. Even though we can't always solve all of the problems in the aura of a given prototype, we shall discover that just describing and thinking about them will be a valuable learning experience. Aura #3 below is particularly amazing in this regard. Here are three of the most interesting examples from CSE 21, Fall 1997:

(1) Aura #1 (material in Schaum)

(2) Aura #2 (material in Schaum)

(3) Aura #3 (material in Epp, Chapter 11 - directed graphs)