1. Design a test set for a spell checker. Then run the tests on a word processor having a spell checker, and report on possible, inadequacies with respect to your requirements. 2. Give proof rules for statements not covered in this chapter, such as for loops and case. 3. Prove the correctness of the sorting program fragment proposed in Exercise 6.47. Exercise 47 Consider the following sorting program fragment: Select a number of “significant” execution paths, and find values of array a that cause their traversal.