{"type":"ScholarlyArticle","title":"Analysing Temporal Reasoning in Description Logics Using Formal Grammars (IJCAI Extended Abstract)","authors":[{"name":"Camille Bourgaux","slug":"camille-bourgaux","given":"Camille","family":"Bourgaux","affiliation":""},{"name":"Anton Gnatenko","slug":"anton-gnatenko","given":"Anton","family":"Gnatenko","affiliation":""},{"name":"Michaël Thomazo","slug":"michael-thomazo","given":"Michael","family":"Thomazo","affiliation":""}],"abstract":"We establish a correspondence between (fragments of) TEL^o, a temporal extension of the EL description logic with the LTL operator O^k, and some specific kinds of formal grammars, in particular, conjunctive grammars (context-free grammars equipped with the operation of intersection). This connection implies that TEL^o does not possess the property of ultimate periodicity of models, and further leads to undecidability of query answering in TEL^o, closing a question left open since the introduction of TEL^o. Moreover, it also allows to establish decidability of query answering for some new interesting fragments of TEL^o, and to reuse for this purpose existing tools and algorithms for conjunctive grammars.","doi":"10.24963/ijcai.2026/918","url":"https://ijcai.org/proceedings/2026/918","pdf":"https://ijcai.org/proceedings/2026/0918.pdf","markdown":"https://ijcai.org/proceedings/2026/918.md","bibtex":"https://ijcai.org/proceedings/2026/bibtex/918","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":"Sister Conferences Best Papers","track":"Sister Conferences Best Papers","number":918,"pages":{"first":8232,"last":8236},"keywords":["Knowledge Representation and Reasoning: Description logics and ontologies","Knowledge Representation and Reasoning: Qualitative, geometric, spatial, and temporal reasoning","Knowledge Representation and Reasoning: Computational complexity of reasoning"],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}