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Call for Participation: Workshop on AI and Theorem Provers in Mathematics (AITPM)
by Achim D. Brucker 09 Mar '26

09 Mar '26

The Workshop on AI and Theorem Provers in Mathematics (AITPM) will explore with leading experts some of the recent developments related to the use of AI and theorem provers in mathematics as well as the perspectives for such future use. - Workshop website: https://aitpm.github.io/ - Venue: Online - Attendance is free. - Registration: https://forms.office.com/e/c7gth3Rb6Q - Date: 8. - 10. April 2026 ## Speakers - Kevin Buzzard (Imperial College) - Minhyong Kim (International Centre for Mathematical Sciences, Edinburgh) - Yang-Hui He (London Institute for Mathematical Sciences) - Paola Iannone (University of Edinburgh) - Shinichi Mochizuki (Research Institute for Mathematical Sciences Kyoto) - Leonardo De Moura (Amazon Web Services) - Lawrence Paulson (University Cambridge) - Chelsea Edmonds (University of Western Australia) - Patrick Massot (University Paris Saclay) ## Programme Schedule (to be confirmed) The preliminary schedule of the workshop is: * April 8th 2026 * 08:00-09:00 Kevin Buzzard * 09:15-10:15 Paola Iannone * 10:45-11:45 Lawrence Paulson * 12:00-13:00 Discussion/panel session * April 9th 2026 * 08:00-09:00 Chelsea Edmond * 09:15-10:15 Yang Hui Heen * 10:45-11:45 Shinichi Mochizuki * 12:00-13:00 Discussion session * April 10th 2026 * 15:00-16:00 Patrick Massot * 16:15-17:15 Leonardo De Moura * 17:45-18:45 Natarajan Shankar (tbc) * 19:00-20:00 Discussion/panel session and closure All times are BST (i.e., London, observing daylight saving time). ## Organisers - Mohamed Saidi (Department of Mathematics and Statistics, University of Exeter) - Barrie Cooper (Department of Mathematics and Statistics, University of Exeter) - Gihan Marasingha (Department of Mathematics and Statistics, University of Exeter) - Achim D. Brucker (Department of Computer Science, University of Exeter) - Diego Marmsoler (Department of Computer Science, University of Exeter) -- Prof. Achim Brucker | Chair in Cybersecurity & Head of Group | University of Exeter https://www.brucker.ch | https://logicalhacking.com/blog @adbrucker | @logicalhacking

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Cabal transitive constraint puzzle
by Viktor Dukhovni 05 Mar '26

05 Mar '26

Dear Cafe and GHC-devs, I am happy to see that Yamamoto-san (cc:d) (the maintainer of the `tls` package) is extending it to include support for MLKEM key agreement. This in turn depends on the `mlkem` library by Olivier Chéron (also many thanks!). Now it turns out that for maximum portability, `mlkem` in turn has a build flag `use_crypton` that selects either `crypton`, or (current default) the older `cryptonite` library as its dependency. So the dependen graph is: tls <- mlkem <- if (use_crypton): crypton else: cryptonite But, at this, point `tls` is crypton-only, and no longer builds with the older cryptonite equivalents. Therefore `tls` adds constraints: mlkem +use_crypton to its `cabal.project` file, which solves the problem for `tls`, but sadly not for any projects that in turn depend on `tls`. To them the constraints in the `cabal.project` file of `tls` are effectively invisible. Since the default flag value in `mlkem` is for now `use_crypton: false`, each project that wants to use the (work-in-progress) `tls` appears to need to explictly know that `tls` requires a non-default build of `mlkem`, and must add the same constraints to its `cabal.project`. That transitive explicit configuration requirement is not something one can reasonably ask projects that depend on `tls to have to add. And of course, more generally, any other such indirect flag-dependent conflict must not become a burden on all consumers of library B that is only compatible with a specific variant of library C. How is this situation supposed to be handled? Is there something in cabal that can automatically convince the solver to select a setting of the `mlkem` flag that is compatible with `tls`? Must `mlkem` be forked instead to be two libraries, one dependent on `cryptonite` and another dependent on `crypton`? I've been unable to find a satisfactory workaround. Any help appreciated. -- Viktor.

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How to unsubscribe?
by Tom Ellis 05 Mar '26

05 Mar '26

Does the footer appear like this to everyone else? _______________________________________________ Haskell-Cafe mailing list -- haskell-cafe(a)haskell.org To (un)subscribe, modify options or view archives go to: Only members subscribed via the mailman list are allowed to post. "go to" where? Does anyone know how to unsubscribe? Thanks, Tom

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Hackage treatment of source code
by Olaf Klinke 02 Mar '26

02 Mar '26

In the past I had no problem with copy & paste from the colorized html that is produced by haddock. Perhaps some browsers/window managers attempt to copy html as html and not plain text, which may obfuscate this experience. As Brandon said, download & unpack the tar.gz linked from a package's main page to obtain the raw source. No need to reach for cabal. Olaf

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Hackage treatment of source code
by Douglas McIlroy 01 Mar '26

01 Mar '26

Hackage allows one to retrieve "source". However, the so-called source code can't be used, because it is a colorized .html file, not .hs. Even if one wants to use only a snippet of what's on the screen, one must turn to the heavy artillery of Cabal to get it. Can there not be an option to retrieve plain text from Hackage without interposing the colorizer? Doug McIlroy

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Appreciation
by Volker Wysk 28 Feb '26

28 Feb '26

Hi! I've set up my Haskell environment with GHCup and Cabal and compiled a program of mine. It has worked really really well. The developers have my thanks and appreciation. Cheers, Volker

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finding out ghc version from closed issue
by Zoran Bošnjak 27 Feb '26

27 Feb '26

Dear members, I am facing this problem with ghc-9.10.3: https://gitlab.haskell.org/ghc/ghc/-/issues/25477 It looks like the problem is already fixed at some later version. My question is... how do I find out the ghc version from the issue or from the git commit? Zoran

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tls: Hybrid key exchange of ECC and Post-Quantum
by Kazu Yamamoto 26 Feb '26

26 Feb '26

Hello, TLS client of OpenSSL version 3.5 or later specifies hybrid key exchange of ECC and Post-Quantum (such as X25519MLKEM768) and an ECC key exchange (such as X25519) in TLS ClientHello. I have implemented both the hybrid algorithms and the OpenSSL specifying-method in the Haskell "tls" library. Interop with OpenSSL is quite good. I would like to discuss how to specify algorithms in ClientHello before releasing. If you are interested, I would like to invite you to this issue: https://github.com/haskell-tls/hs-tls/issues/516 I thank Olivier Chéron for implementing excellent "mlkem" library. --Kazu

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Midlands Graduate School, 13-17 April 2026, Nottingham, UK
by Graham Hutton (staff) 26 Feb '26

26 Feb '26

Dear all, Registration is now open for the Midlands Graduate School (MGS) in Nottingham! Eight fantastic courses on type theory, category theory, lambda calculus, and more. 13-17 April 2026, Nottingham, UK. Registration closes Sunday 22nd March. Best wishes, Graham ========================================================== MIDLANDS GRADUATE SCHOOL 2026 13-17 April 2026, Nottingham, UK https://tinyurl.com/MGS-2026 ========================================================== BACKGROUND The Midlands Graduate School (MGS) in the Foundations of Computing Science provides a yearly programme of courses on the mathematical foundations of computing, and recently celebrated its 25th year. The MGS is primarily aimed at PhD students in their first or second year, but is open to everyone, and has increasingly seen participation from industry. We welcome participants from all over the world! COURSES Eight courses will be given. Participants usually take around four courses, depending on their interests. Invited course: - Implement your POPL paper (using Haskell) Stephanie Weirich (Pennsylvania) Introductory courses: - Type Theory using Agda Thorsten Altenkirch (Nottingham) - Category Theory Sergey Goncharov (Birmingham) - Lambda Calculus and Combinatory Algebra Sam Speight (Birmingham) Advanced courses: - Effects and Call-By-Push-Value Paul Blain Levy (Birmingham) - Synthetic Homotopy Theory Axel Ljungström (Nottingham) - Categorical Algebra and Logic Sean Moss (Birmingham) - Inductive and Coinductive Reasoning with Isabelle/HOL Andrei Popescu (Sheffield) REGISTRATION Student participants: £350 (or £600 with accommodation) Industry participants: £800 (or £1050 with accommodation) The registration fee includes all lecture courses and example classes, lunch and coffee breaks, and the conference dinner. The 'with accommodation' options include five nights at Rutland Hall with shared bathroom facilities. Registration closes Sunday 22nd March. Spaces are limited, so please register early to secure your place. SPONSORSHIP We offer a range of sponsorship opportunities for industry (bronze, silver, gold and platinum), each with specific benefits. Please see the website for further details. LOCAL ORGANISERS For any queries, please contact the local organisers: Ulrik Buchholtz <ulrik.buchholtz(a)nottingham.ac.uk> Dan Marsden <dan.marsden(a)nottingham.ac.uk> ========================================================== -- Professor Graham Hutton School of Computer Science University of Nottingham, UK http://people.cs.nott.ac.uk/pszgmh This message and any attachment are intended solely for the addressee and may contain confidential information. If you have received this message in error, please contact the sender and delete the email and attachment. Any views or opinions expressed by the author of this email do not necessarily reflect the views of the University of Nottingham. Email communications with the University of Nottingham may be monitored where permitted by law.

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Call for Talks: Haskell Implementors' Workshop 2026
by Christiaan Baaij 19 Feb '26

19 Feb '26

Haskell Implementors' Workshop 2026 https://haskell.foundation/events/2026-haskell-implementors-workshop.html June 5, 2026 Organized by the Haskell Community Co-located with ZuriHac 2026 and Haskell Ecosystem Workshop 2026 Hosted by the Haskell Foundation at Eastern Switzerland University of Applied Sciences (OST) https://www.ost.ch/en/university-of-applied-sciences/campus/rapperswil-jona… Important dates --------------- Deadline: April 10, 2026 (AoE) Notification: May 8, 2026 Workshop: June 5, 2026 The 18th Haskell Implementors' Workshop is to be held alongside ZuriHac 2026 this year near Zurich. It is a forum for people involved in the design and development of Haskell implementations, tools, libraries, and supporting infrastructure to share their work and to discuss future directions and collaborations with others. Talks and/or demos are proposed by submitting an abstract, and selected by a small program committee. There will be no published proceedings. The workshop will be informal and interactive, with open spaces in the timetable and room for ad-hoc discussion, demos, and short lightning talks. Scope and target audience ------------------------- The Implementors' Workshop is an ideal place to describe a Haskell extension, describe works-in-progress, demo a new Haskell-related tool, or even propose future lines of Haskell development. Members of the wider Haskell community are encouraged to attend the workshop -- we need your feedback to keep the Haskell ecosystem thriving. Students working with Haskell are especially encouraged to share their work. The scope covers any of the following topics. There may be some topics that people feel we've missed, so by all means submit a proposal even if it doesn't fit exactly into one of these buckets: * Compilation techniques * Language features and extensions * Type system implementation * Concurrency and parallelism: language design and implementation * Performance, optimisation and benchmarking * Virtual machines and run-time systems * Libraries and tools for development or deployment Talks ----- We invite proposals from potential speakers for talks and demonstrations. We are aiming for 20-minute talks with 5 minutes for questions and changeovers. We want to hear from people writing compilers, tools, or libraries, people with cool ideas for directions in which we should take the platform, proposals for new features to be implemented, and half-baked crazy ideas. Please submit a talk title and abstract of no more than 300 words. Submissions can be made via this form https://forms.gle/S8fpAgFaFEvqoMqH6 until April 10 (anywhere on earth). We will also have a lightning talks session. These have been very well received in recent years, and we aim to increase the time available to them. Lightning talks should be ~7mins and are scheduled on the day of the workshop. Suggested topics for lightning talks are to present a single idea, a work-in-progress project, a problem to intrigue and perplex Haskell implementors, or simply to ask for feedback and collaborators. Program Committee ----------------- * Andrew Lelechenko * Avi Press * Christiaan Baaij (chair) * Gergo Erdi * Jeffrey Young Contact ------- * Christiaan Baaij <chrisitaan.baaij at gmail.com>

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