{"type":"ScholarlyArticle","title":"Approximate Heuristic Search for Semi-Decentralized Systems","authors":[{"name":"Mahdi Al-Husseini","slug":"mahdi-al-husseini","given":"Mahdi","family":"Al-Husseini","affiliation":""},{"name":"Kyle H. Wray","slug":"kyle-h-wray","given":"Kyle H.","family":"Wray","affiliation":""},{"name":"Isaac R. Ward","slug":"isaac-r-ward","given":"Isaac R.","family":"Ward","affiliation":""},{"name":"Mykel J. Kochenderfer","slug":"mykel-j-kochenderfer","given":"Mykel J.","family":"Kochenderfer","affiliation":""}],"abstract":"Achieving optimal coordination in multiagent systems involves a trade-off between intractable centralized planning and suboptimal decentralized execution. We bridge this gap by introducing Approximate Recursive Small Step-Semi-Decentralized A* (RS-SDA*), a tree search algorithm that exploits time-varying centralization during periods of available communication conditioned on the environment or joint actions. By interleaving offline planning with online search and using relaxed heuristics, RS-SDA* achieves high solution quality with reduced computational overhead. SDec-POMDP benchmark experiments show that Approximate RS-SDA* often finds near exact optimal solutions in less than 1% of the time required by exact algorithms. We show scalability in six labyrinth environments both deterministic and stochastic state transitions, and demonstrate real-world feasibility with a multi-drone search-and-rescue simulation in the DARPA Subterranean Challenge cave system.","doi":"10.24963/ijcai.2026/2","url":"https://ijcai.org/proceedings/2026/2","pdf":"https://ijcai.org/proceedings/2026/0002.pdf","markdown":"https://ijcai.org/proceedings/2026/2.md","bibtex":"https://ijcai.org/proceedings/2026/bibtex/2","volume":{"slug":"2026","title":"Proceedings of the Thirty-Fifth International Joint Conference on Artificial Intelligence","short_title":"IJCAI 2026","url":"https://ijcai.org/proceedings/2026/","year":2026,"location":"Bremen, Germany","dates":"15-21 August 2026","editors":"Diego Calvanese","isbn":"978-1-956792-09-6","publisher":"International Joint Conferences on Artificial Intelligence Organization","doi_prefix":"10.24963/ijcai.2026"},"section":"Agent-based and Multi-agent Systems","track":"Main Track","number":2,"pages":{"first":12,"last":19},"keywords":["Agent-based and Multi-agent Systems: Applications","Agent-based and Multi-agent Systems: Agent communication","Agent-based and Multi-agent Systems: Coordination and cooperation","Agent-based and Multi-agent Systems: Multi-agent planning","Agent-based and Multi-agent Systems: Agent-based simulation and emergence"],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}