Joint Workshop on
Explainable Logic-Based Knowledge Representation (XLoKR) and
Explanations with Constraints and Satisfiability (ExCoS)
Co-located with the 9th Federated Logic Conference (FLOC) 2026
July 24, 2026 Lisbon, Portugal
The increasing deployment of autonomous and intelligent systems in critical domains such as healthcare, finance, and cyber-physical systems raises an urgent need for systems that are not only correct, but also explainable. While progress in machine learning has led to strong predictive capabilities, many methods are difficult to interpret and explain. In contrast, logic-based knowledge representation and reasoning methods, as well as constraint solving techniques, provide symbolic structures that facilitate explanation. However, producing explanations that are comprehensible, trustworthy, and useful to different classes of users remains an open challenge.
The goal of this joint workshop is to bring together two communities that have been working in parallel on these challenges:
Explainable Logic-Based Knowledge Representation (XLoKR): this series of workshops has since 2020 provided a forum for discussing how symbolic knowledge representation and reasoning can provide explanations of the behaviour of symbolic and sub-symbolic AI systems. Previous editions of XLoKR took place alongside KR in Greece (Rhodes, virtual 2020), Vietnam (Hanoi, virtual 2021), Israel (Haifa, 2022), Greece (Rhodes, 2023), Vietnam (Hanoi, 2024) and Australia (Melbourne, 2025).
Explanations with Constraints and Satisfiability (ExCoS): this workshop focuses on methods for making constraint solving algorithms and tools more explainable, and the use of solvers to compute explanations in applications such as planning and machine learning. The first edition took place alongside CP/SAT in Scotland (Glasgow, 2025).
Both perspectives highlight the need for symbolic, logic-based reasoning systems that produce human-understandable explanations. By combining these workshops, we aim to foster interaction between researchers in knowledge representation, automated reasoning, constraint solving, satisfiability, and explainable AI, thereby opening new opportunities for cross-fertilization. The program is designed to explore how these shared goals manifest across various sub-fields of AI and logic. Specifically, the topics covered include, but are not limited to explanations for or supported by:
Answer set programming
Automated planning
Automated reasoning
Combinatorial optimization
Computational argumentation
Constraint Solving
Description logics
Formal Explanations
Model counting
Non-monotonic reasoning
Probabilistic reasoning
Satisfiability
Paper Submission: April 17, 2026
Notification: May 25, 2026
Camera-ready papers: July 3, 2026
Workshop: July 24, 2026
We invite extended abstracts of 2–5 pages (excluding references) on topics related to explainability in symbolic, logic-based AI. Reviewing will be single-blind. The papers should be formatted using the LIPIcs style and must be submitted via
Since the workshop will only have informal proceedings and the main purpose is to exchange ideas and results as well as receive feedback from the other participants in a true workshop-style enviroments, we welcome both contributions presenting unpublished results and previously published results that fall within the scope of the workshop. For submissions of already-published works, the submission may consist of the original published paper together with a note stating the publication venue and year. To avoid conflicts with previous/future publications, we will make accepted contributions which have not been published before available on the website (unless the authors wish to opt out of this option).
Tias Guns KU Leuven, Belgium
Matti Järvisalo University of Helsinki, Finland
Francesco Leofante Imperial College London, UK
Nico Potyka Cardiff University, UK
Alexey Ignatiev Monash University, Australia
Antonio Rago King‘s College London, UK
Bart Bogaerts KU Leuven, Belgium
Cem Okulmus Paderborn University, Germany
Christopher Jefferson University of St Andrews, Scotland
Claude-Guy Quimper University Laval, Canada
Cristian Molinaro Università della Calabria, Italy
Emir Demirovic TU Delft, the Netherlands
Fabrizio Russo Imperial College London, UK
Francesco Ricca University of Calabria, Italy
Franz Baader TU Dresden, Germany
Helmut Simonis University College Cork, Ireland
Ignace Bleukx KU Leuven, Belgium
Jean-Marie Lagniez CRIL, France
Jeremias Berg University of Helsinki, Finland
Jip J. Dekker Monash University, Australia
Lucas Kletzander TU Wien, Austria
Maria Garcia de la Banda Monash University, Australia
Michael Hartisch University of Passau, Germany
Nysret Musliu TU Wien, Austria
Pierre Marquis CRIL, U. Artois & CNRS, France
Rafael Peñaloza University of Milano-Bicocca, Italy
Roberta Calegari Alma Mater Studiorum–Università di Bologna, Italy
Ruth Hoffmann University of St Andrews, UK
Stefan Borgwardt TU Dresden, Belgium
Stefan Schlobach Vrije Universiteit Amsterdam, Netherlands
Stefan Szeider TU Wien, Austria
Thomas Lukasiewicz Vienna University of Technology, Austria
Xiang Yin Imperial College London, UK
Zeynep G. Saribatur TU Wien, Austria
Xiaxia Wang University of Oxford, UK
Zhiliang Xiang Cardiff University, UK
For organizational questions, please contact us at xlokrexcos@gmail.com.