Abstract
We introduce a natural sequent calculus for preferential conditional logic PCL via embeddings into provability logic GL, achieving optimal complexity and enabling countermodel extraction. Extending the method to PCL with reflexivity and absoluteness – corresponding to Åqvist’s deontic system F with cautious monotony – we employ hypersequents to capture the S5 modality; the resulting calculus subsumes the known calculi for the weaker systems E and F within Åqvist family.
Agata Ciabattoni
Professor of Non-Classical Logics in Computer Science
Agata Ciabattoni is a full professor of non-classical logics in computer science. She is an expert in proof theory for non-classical logics and their applications in various fields. Among other things, she has been investigating proof theory for deontic logic, its applications in AI, connections to legal reasoning, and formalisation of the deontic reasoning of the Mı̄māmsā school of Indian philosophy.
Matteo Tesi
PostDoc Researcher (Marie Curie Individual Fellowship)
Matteo’s research focuses on non-classical (modal, intermediate, and substructural) logics, structural proof theory and their philosophical applications. He has worked with sequent calculi and their generalizations (hypersequents, nested sequents, and labelled sequents) to offer analytic presentations of families of non-classical logics.