IPP

[Koehler et al.1997] extends the Graphplan [Blum Furst1997] algorithm to accept a richer plan description language. In its early versions, this language was a subset of ADL that extends the STRIPS formalism of Graphplan to allow for conditional and universally quantified effects in operators. Until version 4.0, negation was handled via the introduction of new predicates for the negated preconditions and corresponding mutual exclusion rules; subsequent versions handle it directly [Koehler1999]. We used the AIPS98 version of IPP as well as the later 4.0 version.