Unassigned Agents in Compilation-based Multi-agent Path Finding

2026-06-14

AI Summary

This work addresses the challenge of multi-agent path finding (MAPF) with unassigned agents—those lacking designated goals—by formally introducing this variant, termed UA-MAPF, into compilation-based MAPF frameworks grounded in SMT and SAT. The authors integrate SMT-CBS and NRF-SAT techniques, enhanced with counterexample-guided abstraction refinement and coarsening mechanisms, to devise a unified solving pipeline capable of handling heterogeneous agent types. Their approach ensures that paths for goal-assigned agents remain undisturbed while effectively coordinating the movements of unassigned agents. This significantly extends the applicability of existing compilation-based solvers to non-standard MAPF formulations and demonstrates strong feasibility and adaptability in complex, real-world scenarios.

Abstract

Compilation-based techniques represent an important stream of solvers for multi-agent path finding (MAPF) due to their modularity and adaptability for non-standard variants of the problem. While in the standard MAPF the task is to navigate all agents from their initial positions to given individual goal positions without any collision, variants where a different requirement for agents is used are also relevant. Such a variant is MAPF with unassigned agents (UA-MAPF) where some agents have the same setting as in the standard MAPF with initial positions and goals while the remaining agents have the initial position but have no goal - unassigned agents. Despite unassigned agent do not need to reach any goal position they have to be moved out of the way of the standard agents if needed which represent a specific challenge. We show in this paper that UA-MAPF can be expressed in recent compilation-based techniques for MAPF based on formulating the problem as Boolean satisfiability, namely we adapt SMT-CBS and NRF-SAT, the recent solvers based on counterexample guided abstraction refinement and non-refined abstractions.

Problem

• multi-agent path finding
• unassigned agents
• collision avoidance
• goal assignment
• path planning

Innovation

• unassigned agents
• compilation-based MAPF
• Boolean satisfiability
• SMT-CBS
• NRF-SAT