Do problems 4.1, 4.2, and 4.5, and 4.21.
Exercise 4.6 gives some upper-bound operators some of which may be widening operators. Give examples of each on the lattice Interval and for each of your examples, determine whether it is a widening operator. Explain your answer in words (not math symbols!).
As with all homeworks, please turn in your homework on paper at the beginning of lecture.