{"type":"ScholarlyArticle","title":"A Structural Complexity Analysis of Hierarchical Task Network Planning","authors":[{"name":"Cornelius Brand","slug":"cornelius-brand","given":"Cornelius","family":"Brand","affiliation":""},{"name":"Robert Ganian","slug":"robert-ganian","given":"Robert","family":"Ganian","affiliation":""},{"name":"Fionn Mc Inerney","slug":"fionn-mc-inerney","given":"Fionn","family":"Mc Inerney","affiliation":""},{"name":"Simon Wietheger","slug":"simon-wietheger","given":"Simon","family":"Wietheger","affiliation":""}],"abstract":"We perform a refined complexity-theoretic analysis of three classical problems in the context of Hierarchical Task Network Planning: the verification of a provided plan, whether an executable plan exists, and whether a given state can be reached. Our focus lies on identifying structural properties which yield tractability. We obtain new polynomial algorithms for all three problems on a natural class of primitive networks, along with corresponding lower bounds. We also obtain an algorithmic meta-theorem for lifting polynomial-time solvability from primitive to general task networks, and prove that its preconditions are tight. Finally, we analyze the parameterized complexity of the three problems.","doi":"10.24963/ijcai.2025/489","url":"https://ijcai.org/proceedings/2025/489","pdf":"https://ijcai.org/proceedings/2025/0489.pdf","markdown":"https://ijcai.org/proceedings/2025/489.md","bibtex":"https://ijcai.org/proceedings/2025/bibtex/489","volume":{"slug":"2025","title":"Proceedings of the Thirty-Fourth International Joint Conference on Artificial Intelligence","short_title":"IJCAI 2025","url":"https://ijcai.org/proceedings/2025/","year":2025,"location":"Montreal, Canada","dates":"16-22 August 2025","editors":"James Kwok","isbn":"978-1-956792-06-5","publisher":"International Joint Conferences on Artificial Intelligence Organization","doi_prefix":"10.24963/ijcai.2025"},"section":"Knowledge Representation and Reasoning","track":"Main Track","number":489,"pages":{"first":4391,"last":4400},"keywords":["Planning and Scheduling: PS: Hierarchical planning","Planning and Scheduling: PS: Theoretical foundations of planning","Knowledge Representation and Reasoning: KRR: Computational complexity of reasoning"],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}