This ontology describes symbols and relations in PDDL. The class of domain definition The list of Domain(s) The list of require-key(s) as Literal The list of drs:Type(s) The super class for all objects Same as Object an object with unknown type The list of Predicate(s) The list of drs:Function(s) The class of action definition The list of Parameter(s) The class of fluent-test definition The class of pddl function definition used in Evaluation contexts The class of pddl action-def_body definition The class of axiom definition The class of situation definition The list of Object Term The list of drs:Atomic formula The class of problem definition