In this section we introduce SOL-EP, the macro system that we used in the fourth international planning competition. We start with a motivation in Section 3.1, and then describe the method in the following two sections. SOL-EP follows the same four-step pattern as before, but can be applied to more general classes of problems. Section 3.2 describes steps 1 - 3, and Section 3.3 shows step 4. Section 3.4 concludes this section with a discussion.