Using Earley Parser for Verification of Totally Ordered Hierarchical Plans

Kristýna Pantucková, Simona Ondrcková, Roman Barták

Abstract: Hierarchical planning extends classical planning by capturing the hierarchical structure of tasks via decomposition of tasks to subtasks. Hierarchical plan verification is the problem of determining whether a given plan is valid according to that structure. As decomposition trees in totally ordered hierarchical planning domains resemble parsing trees of context-free grammars, one may exploit the techniques for context-free grammars also for hierarchical plans. In this paper, we study how the Earley parser, proposed for checking whether a given word belongs to a language defined by context-free grammar, can be extended to verification of totally ordered hierarchical plans.