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COMMA 2026

11th International Conference on Computational Models of Argument

Program Schedule

Schedule

The full three-day programme of COMMA 2026. Times are local to the venue.

Day 1 – Wednesday 16th September

  1. 08:30–08:45
    Welcome

    Welcome and opening remarks

    Vanina Martinez, Lluis Godo and Katie Atkinson

  2. 08:45–09:30
    Memorial

    Memorial session for Tony Hunter

    Elizabeth Black, Victor David, Xuyao Feng and Matthias Thimm

  3. 09:30–09:50
    Logical Accounts of Argumentation

    Toulmin Argumentation Logic

    Floris Bex and Henry Prakken

  4. 09:50–10:10
    Logical Accounts of Argumentation

    Truth Logic and Inquiry: Arguments For The Dialectical Turn in Non-monotonic Reasoning

    Sanjay Modgil

  5. 10:10–10:30
    Logical Accounts of Argumentation

    Defeasible Case-Based Reasoning in Ethics: A Logic-Based Argumentative Model

    Luca Redondi

  6. 10:30–11:00
    Break

    Morning coffee break

  7. 11:00–12:00
    Keynote

    Solving Conflict in Human-Robot Interaction: context, multiple preferences and learning

    Guillem Alenyà

  8. 12:00–12:20
    Structuring Arguments

    Simplifying Structured Arguments in Hierarchical Case-Based Reasoning

    Ilaria Canavotto

  9. 12:20–12:40
    Structuring Arguments

    Constructing Compact Structured Argumentation Frameworks

    Tuomo Lehtonen

  10. 12:40–13:00
    Structuring Arguments

    Probabilistic Subargument Argumentation Frameworks

    Chenyang Cai, Beishui Liao and Chen Chen

  11. 13:00–14:30
    Break

    Lunch break

  12. 14:30–14:50
    Argumentation and Multiagent Systems

    A Framework and Agent Strategies for ASPIC+-Based Advisory Dialogues

    Michael Mueller

  13. 14:50–15:10
    Argumentation and Multiagent Systems

    A Unified Framework for Argumentation Protocols

    Théophile Romieu, Elise Bonzon, Jérôme Delobelle and Julien Rossit

  14. 15:10–15:30
    Argumentation and Multiagent Systems

    The Libra Dialogue Protocol for Comparative Deliberation

    Luca Pasetto, Thomas Skafte, Leendert van der Torre and Liuwen Yu

  15. 15:30–15:50
    Argumentation and Multiagent Systems

    Representation Guarantees for Multi-Agent Knowledge Integration via Abstract Argumentation and Their Computational Complexity

    Naoki Susami and Ryuta Arisaka

  16. 15:50–16:20
    Break

    Afternoon coffee break

  17. 16:20–16:40
    Abstract Argumentation Developments

    On the Role of Premises in Assessing the Strength of Analogical Arguments

    Leila Amgoud, Marco Hanocq and Marie-Christine Lagasquie-Schiex

  18. 16:40–17:00
    Abstract Argumentation Developments

    Assumption-based Argumentation Through the Lens of Approximation Fixpoint Theory

    Iosif Apostolakis, Hannes Strass and Johannes Peter Wallner

  19. 17:00–17:20
    Abstract Argumentation Developments

    Denial Integrity Constraints in Assumption-Based Argumentation

    Giovanni Buraglio, Anna Rapberger and Stefan Woltran

  20. 17:20–17:30
    Break

    Comfort break

  21. 17:30–19:00
    Demo

    Demo session 1

    (See list of presenters in the demo sessions below.)

  22. 19:30
    Social

    Welcome reception

    Hotel Barceló Raval (11th Floor) · Rambla del Raval, 17, Ciutat Vella, 08001 Barcelona

    View on Google Maps

Day 2 – Thursday 17th September

  1. 09:00–09:20
    Innovative Applications Track

    A dialectical argumentation system for collision avoidance between drones

    Evandro Pioli Moro, Elizabeth Black and Anthony Hunter

  2. 09:20–09:40
    Innovative Applications Track

    LLM-Assisted Legal Propositions Identification from Party Arguments in the U.S. Supreme Court Briefs

    Heng Zheng and Alex Zhang

  3. 09:40–10:00
    Innovative Applications Track

    ClinArgES: Clinical Argumentation Spanish Corpus

    Sofía Zakhir-Puig, Vanesa Gómez-Martínez, Miguel Ángel Rodríguez-García, Soto Montalvo and Raquel Martínez

  4. 10:00–10:20
    Innovative Applications Track

    Do Justified Arguments Matter for Bayesian Portfolio Optimisation?

    Anthony Young

  5. 10:20–10:50
    Break

    Morning coffee break

  6. 10:50–11:10
    Argumentation and Explainability

    Identifying Implicit Premises for Logical Reconstruction of Argument Graphs

    Xuyao Feng and Anthony Hunter

  7. 11:10–11:30
    Argumentation and Explainability

    Lost in Translation: Towards Explainable Instantiated Argumentation Frameworks

    Shawn Bowers and Bertram Ludäscher

  8. 11:30–11:50
    Argumentation and Explainability

    Streamlining Argumentative Explanation for A Fortiori Reasoning in Inconsistent Case Bases

    Wachara Fungwacharakorn, Gauvain Bourgne and Ken Satoh

  9. 11:50–12:10
    Argumentation and Explainability

    Beyond But-for Test: Counterfactual Explanation in Abstract Argumentation via Actual Causality

    Siyi Liu, Muyun Shao and Beishui Liao

  10. 12:10–12:30
    Argumentation and Explainability

    How Can Similarity Be Explained? Modeling Multiple Points of View with Inverse simFOL

    Nino Pireaud, Victor David, Pierre Monnin, Elena Cabrio, Serena Villata and Anthony Hunter

  11. 12:30–12:35
    Special

    ICCMA 2026: The International Competition on Computational Models of Argumentation

  12. 12:30–14:00
    Break

    Lunch break

  13. 14:00–14:20
    Argumentation Interfacing with Machine Learning

    Guiding Admissibility Solvers via Co-Admissibility Predictions

    Sandra Hoffmann, Isabelle Kuhlmann and Matthias Thimm

  14. 14:20–14:40
    Argumentation Interfacing with Machine Learning

    A Neural Approach for Incomplete Argumentation Frameworks

    Cassandre Azeau and Jean-Guy Mailly

  15. 14:40–15:00
    Abstract Argumentation Developments

    Explaining Vacuity in Abstract Argumentation

    Theodoros Doukas and Matthias Thimm

  16. 15:00–15:20
    Abstract Argumentation Developments

    On Polymorphic Attacks in ASPIC+

    Pietro Baroni, Federico Cerutti and Massimiliano Giacomin

  17. 15:20–15:50
    Break

    Afternoon coffee break

  18. 15:50–16:10
    Computational Properties of Argumentation

    On the Complexity of Initial Models in Abstract Dialectical Frameworks

    Hannes Strass and Johannes Peter Wallner

  19. 16:10–16:30
    Computational Properties of Argumentation

    On Grounding Extensions in Abstract Argumentation

    Lars Bengel, Shawn Bowers, Bertram Ludäscher and Matthias Thimm

  20. 16:30–16:50
    Computational Properties of Argumentation

    Complexity of Preferred Semantics in Infinite Argumentation

    Uri Andrews and Luca San Mauro

  21. 16:50–17:00
    Break

    Comfort break

  22. 17:00–18:30
    Demo

    Demo session 2

    (See list of presenters in the demo sessions below.)

  23. 20:30
    Social

    Conference Dinner

    Arenal Restaurant · Pg. Marítim de la Barceloneta, s/n, Ciutat Vella, 08003 Barcelona

    View on Google Maps

Day 3 – Friday 18th September

  1. 09:00–09:20
    Abstract Argumentation Semantics

    External Semantics For Argumentation Frameworks

    Yi Yutong and Weiwei Chen

  2. 09:20–09:40
    Abstract Argumentation Semantics

    Cost-Aware Strategic Enforcement: An Analysis of Counting Semantics

    Kenji Imai and Ryuta Arisaka

  3. 09:40–10:00
    Abstract Argumentation Semantics

    Aggregating Ranking-based Semantics in Abstract Argumentation

    Ulla Wege, Kenneth Skiba and Matthias Thimm

  4. 10:00–10:20
    Abstract Argumentation Semantics

    On the Relationship of Unacceptable Arguments to Acceptable Extensions

    John Spoerl

  5. 10:20–10:50
    Break

    Morning coffee break

  6. 10:50–11:50
    Keynote

    Bayesian Argumentation from Single Arguments to Large-Scale Debate

    Ulrike Hahn

  7. 11:50–12:10
    Argumentation and Natural Language Arguments

    Do Argumentation Schemes Help? An Assessment of Their Role in Formalising Natural Language Arguments

    Ameer Saadat-Yazdi, Victor David, Anthony Hunter and Serena Villata

  8. 12:10–12:30
    Argumentation and Natural Language Arguments

    Benchmarking Argumentative Behaviour of LLMs: A Study of Defences Against Character Attacks

    Ewelina Gajewska, Katarzyna Budzynska and Jarosław A. Chudziak

  9. 12:30–12:50
    Special

    Argument and Computation journal update

    Pietro Baroni and Bart Verheij

  10. 12:50–14:00
    Break

    Lunch break

  11. 14:00–14:20
    Computational Linguistics and Argument Mining

    Can Large Language Models Identify Reasoning Patterns in Low-Resource Languages? A Case Study of Argumentation Schemes in Catalan

    Ramon Ruiz-Dolz and Stella Heras

  12. 14:20–14:40
    Computational Linguistics and Argument Mining

    Better than the Gold Standard? Evaluating Human vs. LLM Enthymeme Reconstruction in Natural Language Argumentation

    Ekaterina Sviridova, Elena Cabrio and Serena Villata

  13. 14:40–15:00
    Computational Linguistics and Argument Mining

    An Exploratory Inquiry into Arguing Under Extortion

    Pietro Baroni, Federico Cerutti, Brilant Gashi, Massimiliano Giacomin, Andrea Loreggia and Enrico Scala

  14. 15:00–15:20
    Computational Linguistics and Argument Mining

    Multimodal Stance Detection in Controversial Tweets

    Deborah Dore, Diego Blassio, Elena Cabrio and Serena Villata

  15. 15:20–15:50
    Break

    Afternoon coffee break

  16. 15:50–16:10
    Logical Accounts of Argumentation

    A Conversation-Based Approach to Doxastic and Deontic Inference

    Kees van Berkel, Isabella Cissell and Blaž Istenič Urh

  17. 16:10–16:30
    Logical Accounts of Argumentation

    Satisfying Rationality Postulates of Structured Argumentation Through Deductive Support

    Tom Friese and Marcos Cramer

  18. 16:30–16:50
    Logical Accounts of Argumentation

    Forgetting in ASPIC+: formulas, premises, rules and conclusions

    Annemarie Borg

  19. 16:50–17:10
    Logical Accounts of Argumentation

    Argument Accrual, ASPIC+ and Bipolar Argumentation Frameworks

    Henry Prakken

  20. 17:10–17:15
    Closing

    Closing remarks

    Vanina Martinez, Lluis Godo and Katie Atkinson

Demonstrations

Two demo sessions will be held during the conference, one on Day 1 (17:30–19:00) and one on Day 2 (17:00–18:30)

Day 1 – Wednesday 16th September

(5 demos)
  1. ABDA-NL: A Natural-Language Scenario Explorer for Argument-Based Reasoning Shawn Bowers, Martin Caminada, Haoyang Liu and Bertram Ludäscher
  2. ADICT: Argumentative Dialogue Convergence Tracker Youcef Islam Ghodbane, Yann Gabay, Gowrishankar Ganesh and Madalina Croitoru
  3. Argumentation-based Causal Reasoning Lars Bengel, Oleksandr Dzhychko, Myriam Kasten, Kai Sauerwald and Matthias Thimm
  4. ArgNotator: A web based annotation tool for the periodic table of arguments Ameer Saadat-Yazdi and Nadin Kokciyan
  5. Tag Me Maybe: A Flexible Environment for Annotating Argumentation Daniel Ziembicki

Day 2 – Thursday 17th September

(5 demos)
  1. The Jiminy moral advisor: a Python implementation Francisco J. Rodriguez Lera, Miguel Ángel González-Santamarta and Pere Pardo
  2. ArguScope: A Visual Argumentation Tool for Priority-Aware Reasoning Jack Mumford, Nataliya Gulay, Dmytro Antypov, Luke M. Daniels, Matthew S. Dyer, Sven Schewe, Katie Atkinson and Matthew J. Rosseinsky
  3. ArgBlazer: Exploring Decision Landscapes Using Argumentation Frameworks Meng Li, Timothy McPhillips, Shawn Bowers and Bertram Ludäscher
  4. Safety, Liveness, and Fairness in Quantitative Argumentation Dialogues Arunavo Ganguly, Julian Alfredo Mendez and Timotheus Kampik
  5. Arguments and Debates as Classically Typed Programs Max Rapp

Workshop Schedule

Workshops run across two days prior to the main conference. Times are local to the venue.

Day 1 — Workshops · 14 September 2026

Workshops on 14 September 2026: CMNA'26 · LNGAI 2026

  1. 08:30
    Schedule

    Registration Opens

  2. 09:00
    Schedule

    Workshops Start Time

  3. 10:30 – 11:00
    Break

    Morning Coffee Break

  4. 12:30 – 14:00
    Break

    Lunch

  5. 15:30 – 16:00
    Break

    Afternoon Coffee Break

  6. 17:30
    Schedule

    Workshops Finish Time

Day 2 — Workshops · 15 September 2026

Workshops on 15 September 2026: SAFA 2026 · CERCA

  1. 08:30
    Schedule

    Registration Opens

  2. 09:00
    Schedule

    Workshops Start Time

  3. 10:30 – 11:00
    Break

    Morning Coffee Break

  4. 12:30 – 14:00
    Break

    Lunch

  5. 15:30 – 16:00
    Break

    Afternoon Coffee Break

  6. 17:30
    Schedule

    Workshops Finish Time

Invited Talks

Ulrike Hahn

Birkbeck College, University of London, UK

Bayesian Argumentation from Single Arguments to Large-Scale Debate

Abstract

Over the past decades, the framework of Bayesian probability has successfully been applied to the task of evaluating argument quality: that is, the nuanced evaluation of content-based differences in argument strength for individual arguments, at least in the domain of facts. The Bayesian framework also deals naturally with the problem of aggregation that has bedevilled both argumentation theory and the design of practical argumentation systems. That is, it can provide overall, summary evaluation across multiple arguments in such a way as to yield a final conclusion strength. In this, it is complementary to other formal and computational approaches to argument that have focussed on the dialectical process of argument. The talk describes how core dialectical notions (such as defeat) are captured in a Bayesian framework. It then introduces ways in which it opens up research questions and facilitates progress in understanding what is simultaneously both one of the most important real-world forms of argument and one of the most neglected by argumentation theorists: polylogues involving argument across large groups such as online social networks.

Bio

Ulrike Hahn

Ulrike Hahn is a professor at the Department of Psychological Sciences at Birkbeck College, University of London, where she also serves as director of the Centre for Cognition, Computation and Modelling. Ulrike's main focus has been on questions of human rationality. Her research examines human judgment, decision-making, and the rationality of everyday argument. In recent years she has been particularly interested in how the larger communicative social networks that we are part of shape the accuracy of our beliefs. Here she has used Bayesian agent-based models to understand argument exchange within larger collectives. Ulrike has been a member of the Senior Editorial Board of Topics in Cognitive Science, an Action Editor for Psychonomic Bulletin & Review, for Cognitive Psychology, and, currently, is an AE for Psychological Science and a consulting editor for Psychological Review. She was awarded the Cognitive Section Prize by the British Psychological Society, the Kerstin Hesselgren Professorship by the Swedish Research Council, and the Anneliese Maier Research Award by the Alexander von Humboldt Foundation. She is a fellow of the German National Academy of Science (Leopoldina), a fellow of the Association for Psychological Science, a fellow of the Cognitive Science Society, and she received an honorary doctorate from Lund University, Sweden in 2017.

Guillem Alenyà

Institut de Robotica i Informàtica Industrial (IRI), CSIC and UPC, Barcelona

Solving conflicts in human-robot interaction: context, multiple-preferences, and learning

Abstract

Autonomous agents operating in unstructured human environments must perform continuous decision-making under high degrees of uncertainty. These processes are typically constrained by partially observable states, stochastic sensor noise, and aleatory model inaccuracies. To mitigate these challenges, formal argumentation systems provide a robust framework for disambiguation and verifiable explainability (XAI). Within the domain of assistive robotics, such systems enable agents to synthesize multi-user context and conflicting arguments into coherent action policies. Furthermore, we highlight the advantage that the agent can proactively initiate active information-gathering tasks to resolve knowledge gaps and refine its internal world model.

Bio

Guillem Alenyà

Guillem Alenyà is a Researcher and Director at the Institut de Robotica i Informàtica Industrial (IRI), a joint centre of the Spanish Scientific Research Council (CSIC) and Polytechnic University of Catalonia (UPC). In the last 5 years, he has contributed novel approaches to the areas of learning and HRI devoted to facilitating the introduction of robots in human environments, principally in the fields of assistive robotics and garment manipulation. He is currently promoting LabORA, a new Open Lab devoted to bringing Assistive Robotics closer to societal needs. This is a 500m² new facility with an initial investment of 2.5M€ accompanied by the creation of a promoting group initially composed of more than 10 other research groups, hospitals, day-care facilities, service and technology industries, and governmental agencies.

Important Dates

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