{"type":"ScholarlyArticle","title":"Ensuring Logic in the Fog: Sound POMDP Synthesis with LTL Objectives","authors":[{"name":"Can Zhou","slug":"can-zhou","given":"Can","family":"Zhou","affiliation":""},{"name":"Yulong Gao","slug":"yulong-gao","given":"Yulong","family":"Gao","affiliation":""},{"name":"Pian Yu","slug":"pian-yu","given":"Pian","family":"Yu","affiliation":""}],"abstract":"Synthesising autonomous agents that can navigate uncertain environments while adhering to complex temporal constraints remains a fundamental challenge.  While Linear Temporal Logic (LTL) provides a rigorous language for specifying such tasks, the inherent undecidability of qualitatively verifying LTL satisfaction in partially observable Markov decision processes renders quantitative synthesis difficult, especially when designing reliable reward signals for approximate solvers. In this paper, we bridge this gap with a novel, sound reward-shaping mechanism that dynamically generates belief-dependent rewards grounded in certified LTL satisfaction. By integrating this mechanism into an enhanced Monte Carlo Planning framework, we empower agents to navigate the `fog' of partial observability with a search process focused on maximising verifiable success. Our experiments demonstrate that this approach not only thrives in scenarios where existing solvers fail but also maintains effectiveness and scalability across diverse benchmark domains.","doi":"10.24963/ijcai.2026/456","url":"https://ijcai.org/proceedings/2026/456","pdf":"https://ijcai.org/proceedings/2026/0456.pdf","markdown":"https://ijcai.org/proceedings/2026/456.md","bibtex":"https://ijcai.org/proceedings/2026/bibtex/456","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":"Knowledge Representation and Reasoning","track":"Main Track","number":456,"pages":{"first":4097,"last":4105},"keywords":["Planning and Scheduling: POMDPs","Planning and Scheduling: Planning under uncertainty","Planning and Scheduling: Planning with Incomplete Information","Uncertainty in AI: Sequential decision making","Knowledge Representation and Reasoning: Reasoning about actions"],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}