4.3.x. Exercises

Redo the exercises of 4.2.x, looking for opportunities to use the new rules. (Each of the answers in 4.2.xa has as least one alternative using the new rules; and, in most cases, the alternative is much shorter than the one given there.)

Since the exercise machine incorporates detachment rules but not attachment rules, it can be used to produce only some of the alternative derivations that are possible using the rules of this section.