Joseph Y. Halpern was a pioneering computer scientist whose work reshaped how we reason about knowledge, causality, uncertainty, and multi-agent systems. His contributions were foundational and far-reaching — spanning logic, probability, game theory, and distributed computing.
Joe last joined us at KR 2024 in Hanoi, as an invited speaker on the panel "Great Ideas from KR: drawing on the past to shape the future." He received the Ray Reiter Best Paper Prize at KR 2012, among many other high-impact contributions.
This one-day workshop brings together researchers whose work touches Joe's legacy — to celebrate his ideas and carry them forward. It will be held on July 19, 2026 in Lisbon, Portugal, as part of FLoC 2026, co-located with KR 2026.
We are compiling a collection of messages, photos, and short videos from those who knew him, which will be presented to his family as a gift.
Please submit your material using this
Google Form
A few quick guidelines for your submission:
- Videos: If you submit a video, please try to keep it between 30 and 60 seconds and record it in landscape (horizontal) mode.
- File Sizes: The form accepts photos up to 100MB and videos up to 1GB. If you need to submit a larger file, please upload it to Google Drive (or another cloud service) and share the accessible link in the written message prompt on the form.
- Deadline: Please submit your memories by the 10th of July.
We welcome submissions on any topic related to Joe's work and KR, including but not limited to:
- Belief revision
- Causality
- Reasoning about knowledge and uncertainty
- Game theory and multi-agent systems
- Distributed systems and formal verification
Submissions should be extended abstracts of 2–5 pages (excluding references), formatted in one-column style, with author names and affiliations. Reviewing is single-blind.
Accepted contributions will be listed on the workshop website and presented in person.
Submit via the FLoC submission system:
submissions.floc26.org/joefest →All deadlines are AoE — Anywhere on Earth (UTC−12).
| Paper submission deadline | April 27, 2026 |
| Notification of acceptance | May 20, 2026 |
| Early registration deadline | June 1, 2026 |
| Workshop | July 19, 2026 |
- Sander Beckers University College London, UK
- Hana Chockler King's College London, UK
- Esra Erdem Sabancı University, Türkiye
- Ivan Geffner Utrecht University, Netherlands
- Fangzhen Lin Hong Kong University of Science and Technology, Hong Kong
- Evan Piermont Royal Holloway, University of London, UK