The Universal PDDL Domain

TL;DR

This paper shows that it is quite easy to define a PDDL domain such that any propositional planning problem instance, from any domain, becomes an instance of this (lifted)"universal"domain.

Abstract

In AI planning, it is common to distinguish between planning domains and problem instances, where a "domain" is generally understood as a set of related problem instances. This distinction is important, for example, in generalised planning, which aims to find a single, general plan or policy that solves all instances of a given domain. In PDDL, domains and problem instances are clearly separated: the domain defines the types, predicate symbols, and action schemata, while the problem instance specifies the concrete set of (typed) objects, the initial state, and the goal condition. In this paper, we show that it is quite easy to define a PDDL domain such that any propositional planning problem instance, from any domain, becomes an instance of this (lifted) "universal" domain. We construct different formulations of the universal domain, and discuss their implications for the complexity of lifted domain-dependent or generalised planning.

Figures (4)

• Figure 1: The universal domain for propositional planning.
• Figure 2: Example of a problem instance of the universal propositional planning domain.
• Figure 3: A STRIPS formulation of the universal propositional planning domain.
• Figure 4: A STRIPS formulation of the parameterised universal planning domain $D_{3,2,1}$.