Planning with Dynamically Changing Domains

TL;DR

This paper introduces a planning framework for domains where objects can be created or destroyed dynamically, extending classical planning to handle infinite and changing object sets using first-order logic.

Contribution

It formulates a new approach to planning in dynamic domains, ensuring soundness and completeness without the domain closure assumption, applicable to bounded, non-sensing conformant planning.

Findings

Proposed a first-order logic-based planning method for dynamic object domains

Proved the soundness and completeness of the approach

Developed a proof-of-concept implementation

Abstract

In classical planning and conformant planning, it is assumed that there are finitely many named objects given in advance, and only they can participate in actions and in fluents. This is the Domain Closure Assumption (DCA). However, there are practical planning problems where the set of objects changes dynamically as actions are performed; e.g., new objects can be created, old objects can be destroyed. We formulate the planning problem in first-order logic, assume an initial theory is a finite consistent set of fluent literals, discuss when this guarantees that in every situation there are only finitely many possible actions, impose a finite integer bound on the length of the plan, and propose to organize search over sequences of actions that are grounded at planning time. We show the soundness and completeness of our approach. It can be used to solve the bounded planning problems without DCA that belong to the intersection of sequential generalized planning (without sensing actions) and conformant planning, restricted to the case without the disjunction over fluent literals. We discuss a proof-of-the-concept implementation of our planner.