UCPOP

[Barrett et al.1993] is a Partial Order Causal Link planner. The decision to include UCPOP was based on several factors. First, it does not expand quantifiers and negated preconditions; for some domains, the expansion from grounding operators can be so great as to make the problem insolvable. Second, UCPOP is based on a significantly different algorithm in which interest has recently resurfaced. We used UCPOP version 4.1.