Homomorphisms of Lifted Planning Tasks: The Case for Delete-Free Relaxation Heuristics

Rostislav Horčík, Daniel Fišer, Alvaro Torralba

[AAAI-22] Main Track
Abstract: Classical planning tasks are modelled in PDDL which is a schematic language based on first-order logic. Most of the current planners turn this lifted representation into a propositional one via a grounding process. However, grounding may cause an exponential blowup. Therefore it is important to investigate methods for searching for plans on the lifted level. To build a lifted state-based planner, it is necessary to invent lifted heuristics. We introduce maps between PDDL tasks preserving plans allowing to transform a PDDL task into a smaller one. We propose a novel method for computing lifted (admissible) delete-free relaxed heuristics via grounding of the smaller task and computing the (admissible) delete-free relaxed heuristics there. This allows us to transfer the knowledge about relaxed heuristics from the grounded level to the lifted level.

Introduction Video

Sessions where this paper appears

  • Poster Session 3

    Fri, February 25 8:45 AM - 10:30 AM (+00:00)
    Blue 4
    Add to Calendar

  • Poster Session 12

    Mon, February 28 8:45 AM - 10:30 AM (+00:00)
    Blue 4
    Add to Calendar

  • Oral Session 12

    Mon, February 28 10:30 AM - 11:45 AM (+00:00)
    Blue 4
    Add to Calendar