We’re excited to announce that Agata Ciabattoni, Dmitry Rozplokhas, and Matteo Tesi have won the Best Student Paper Prize at the European Conference on Logics in Artificial Intelligence (JELIA) 2025 for their paper “GL-based calculi for PCL and its deontic cousin”!

The paper advances conditional logics, a well-established family of logics that play a key role in knowledge representation and reasoning. These logics capture richer forms of implication than classical logic, including Prototypical (“Typically, if A, then B”), Counterfactual (“If A were the case, then B would be”), Deontic (“B is obligatory under condition A”), and Causal (“A causes B”). While the underlying logics for these interpretations are closely related, they have traditionally been studied in isolation. This work brings them together under a unified framework and develops practical tools to support their use. The research for this paper is part of the project Logical Methods for Deontic Explanations (LoDEx), funded by the Austrian Science Fund FWF.

The European Conference on Logics in Artificial Intelligence (JELIA) was established in 1988 as a workshop to provide a dedicated European platform for emerging research in logic-based approaches to AI. Since then, it has evolved into a leading biennial conference, with proceedings published in Springer’s Lecture Notes in Artificial Intelligence series. JELIA has gained international recognition for its high technical standards and continues to attract a growing number of participants from around the world.

Congratulations to Agata, Dmitry and Matteo on this outstanding achievement!

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 and within Åqvist family.

About the authors

Agata Ciabattoni is Professor and Head of the Research Unit Theory and Logic at TU Wien Informatics. She serves as a board member of the cluster of excellence Bilateral AI, and as co-chair of the Vienna Center for Logic and Algorithms (VCLA). She is the principal investigator of the WWTF-funded projects Training and Guiding AI Agents with Ethical Rules (TAIGER) and Acquiring and explaining norms for AI systems (AXAIS), as well as the project Logical methods for Deontic Explanations (LoDEx), funded by the Austrian Science Fund FWF. She is also a recipient of the FWF START Prize 2011, the highest Austrian award for early-career researchers.

Dmitrii Rozplokhas is a PhD student in the doctoral program Logics for Computer Science at TU Wien Informatics, which is co-funded by the Marie Skłodowska-Curie Actions of the European Commission. Together with Agata Ciabattoni, he was a recipient of the Ray Reiter Best Paper Prize at the 20th International Conference on Principles of Knowledge Representation and Reasoning (KR2023).

Matteo Tesi is a tenure-track researcher in logic, philosophy, and history of science at the Scuola Normale Superiore in Pisa. He earned his PhD in 2023 and subsequently held a Marie Skłodowska-Curie Fellowship at the Research Unit Theory and Logic headed by Agata Ciabattoni Ciabattoni.

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