A Diagrammatic Inter-Lingua for Planning Domain Descriptions

Sentential and diagrammatic representations are two different formalisms for describing domains and problems. Sentential descriptions are usually more expressive than diagrammatic ones, but tend to present a more complex and less intuitive notation. All modern planning domain description languages are sentential. The complexity of sentential formalisms has been of hindrance to the wider dissemination and take up of planning technology beyond the planning research community. As an alternative to such languages, this paper proposes a diagrammatic “inter-lingua” for planning domain descriptions based on setGraphs. SetGraphs represent actions, states and goals in terms of setand graph-theoretic constructs. Through some examples, setGraphs are shown here to yield simpler and more intuitive domain encodings. An abstract formalisation of setGraphs illustrates how the representation can be easily specified using a formal language. SetGraphs are then proven to be at least as expressive as a standard modern propositional planning domain description language. The model proposed is intended to be used as a common “core” representation, suitable to be used across different levels of abstraction, and aimed at facilitating the elicitation, maintenance and re-use of planning domain descriptions during the processes of language development and domain knowledge engineering.