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John Baez (Feb 21 2025 at 21:31):Here's an announcement from the ACT Steering Committee:
The current plan is for @Pawel Sobocinski and @Priyaa Varshinee to run the conference Applied Category Theory 2026 in Tallinn, Estonia: they are at the Tallinn University of Technology. There's a chance this may not happen, only because of the inherent unpredictability of life, so don't buy your tickets just yet - but this is the plan. We thank Pawel and Priyaa very much for volunteering to do this.
James Fairbanks (Feb 22 2025 at 00:09):This is great news! I’m looking forward to it!
John Baez (Feb 26 2025 at 21:31):The ACT conference steering board wants to require all future organizers to live stream the conference. @Pawel Sobocinski and @Priyaa Varshinee have agreed to live stream ACT 2026.
JR Learnstomath (Jun 18 2025 at 06:12):@Pawel Sobocinski @Priyaa Varshinee , could someone volunteer to help organize if they are not physically in Tallinn and/or may not be able to go in person?
John Baez (Oct 27 2025 at 16:19):The next annual conference on applied category theory is in Estonia!
For more details, read on!
John Baez (Oct 27 2025 at 16:20):Deadlines
The conference particularly encourages participation from underrepresented groups. The organizers are committed to non-discrimination, equity, and inclusion. The code of conduct for the conference is available here.
Program Committee Chairs
Program Committee
Teaching & Communication
Organizing Committee
Steering Committee
Elena Di Lavore (Dec 01 2025 at 08:27):Could we please have more details on the new proceedings track about teaching and communication?
As a PC member, I did not receive any information about this new route to publication. I am surprised that a decision that changes the scope of the proceedings was taken without consulting the community nor notifying the PC. Do we have an expert and diverse enough PC to cover the science of teaching? How do we evaluate teaching submissions against papers in applications of category theory?
I believe that the rest of the PC was not informed and never agreed to these changes. So I would like to initiate some open discussion about it.
Paolo Perrone (Dec 01 2025 at 09:21):Wait, what?
(I'm all for teaching and communication, you all know that, but who decided this?)
Chad Nester (Dec 01 2025 at 09:34):I think it would also be good to clarify exactly what the difference would be between a "research" submission and a "teaching and communication" submission. I don't understand what is meant by the latter. Are there any published articles that would fit this category?
Joe Moeller (Dec 01 2025 at 09:40):I think the right people to talk to might be Priyaa or Pawel, neither of which comes on here much.
Chad Nester (Dec 01 2025 at 09:43):I'll point out that the conference has a steering committee (see John's post above), which I would hope was involved. John is on the steering committee, so might know something about it.
John Baez (Dec 01 2025 at 10:15):The idea is to allow papers about the teaching and communication of applied category theory. It's the job of the program committee chairs (@Geoff Cruttwell and @Priyaa Varshinee) to decide on such things and communicate them to the program committee. Priyaa told us (the steering committee) that she'd been discussing this new policy with someone on the program committee, so I assumed that everyone on the program committee had at least heard of this. The program committee shouldn't first find out by reading a public announcement.
Anyway, @Elena Di Lavore and @Paolo Perrone, please raise your concerns with Priyaa and Geoffrey.
Martti Karvonen (Dec 01 2025 at 16:04):Hearing this, I can't help avoid thinking that this could've been created specifically to create space for a similar talk/proceedings paper as the special session on education at QPL 2025, but I hope I'm just jumping to conclusions.
Mario Román (Dec 01 2025 at 20:21):I did write to Priyaa and Geoff, multiple times already, raising these concerns.
They told me that, after discussing with some members of the Steering, they had decided to keep course anyway.
I still think this extra proceedings track should be reconsidered.
Joe Moeller (Dec 01 2025 at 21:12):Martti Karvonen said:
Hearing this, I can't help avoid thinking that this could've been created specifically to create space for a similar talk/proceedings paper as the special session on education at QPL 2025, but I hope I'm just jumping to conclusions.
I haven't been keeping up with QPL. What happened with the session on education that makes it something not worth trying to emulate?
Martti Karvonen (Dec 01 2025 at 21:18):The category was created ad hoc so that the singleton paper that ended up in that category would not be rejected as out of scope. I guess this time the category exists already during the CfP, but if it was created with that paper/some of the authors in mind (let alone them having influenced the matter), I don't think it's ideal as a process.
Joe Moeller (Dec 01 2025 at 21:29):That doesn't sound great. Given how much energy Priyaa has put into trying to increase outreach and education broadly for several years, it's hard to imagine this is something comparable. This point doesn't seem to relate directly to the original point though.
Joe Moeller (Dec 01 2025 at 21:37):I agree with the point that the PC should be chosen so as to be qualified to evaluate along the tracks. At what point specifically should the organizers have done something different knowing they wanted to do this?
John Baez (Dec 01 2025 at 23:13):Two people on the PC are explicitly listed under "Teaching & Communication". Presumably they can evaluate papers in these fields. I doubt people who don't want to referee such papers will be forced to. (I certainly hope not!)
Mario Román (Dec 01 2025 at 23:32):Joe Moeller said:
At what point specifically should the organizers have done something different knowing they wanted to do this?
I think I disagree even with the idea that the PC chairs may unilaterally create a different route to publication, for a topic they are particularly invested on, with different referees, and outside the usual scope of the conference. We would not want ACT proceedings to become a game of Calvinball.
Perhaps a special session or a non-proceedings track could be a more reasonable first experiment. I think the extra proceedings track should be removed.
And in any case, as John said before, the program committee shouldn't first find out by reading a public announcement.
Joe Moeller (Dec 01 2025 at 23:43):I hadn't noticed the separate section in the PC list with teaching and communication people. Now I think I'm getting on the same page.
Jules Hedges (Dec 02 2025 at 12:17):For comparison to prior art, if I remember correctly I sort of unilaterally created the tool demo track in ACT22 (by which I mean I said I wanted to do it and none of the other organisers objected so then it happened). I think tool demo papers were talk-only and not published. I don't remember there being any controversy about it
Elena Di Lavore (Dec 12 2025 at 15:27):Is the extra proceedings track still happening?
If so, no one has contacted the PC yet. But given everyone's reaction, maybe it should be reconsidered.
Bryce Clarke (Feb 12 2026 at 13:05):Has there been a first call for papers sent out already? I could not find it in my email (I know the information is available on the webpage)
Pawel Sobocinski (Feb 12 2026 at 14:01):Yes it has -- Priyaa has been sending it out to various mailing lists. It was sent out on the CT mailing list on 27 October 2025.
Chad Nester (Feb 12 2026 at 14:06):Sure enough:
#community: mailing list mirror > Applied Category Theory 2026: First Call for Papers
Chad Nester (Feb 12 2026 at 14:07):The link to the "detailed call for papers" seems to be broken (possibly an artifact of mirroring the mailing list on Zulip), but there's a working link to the cfp closer to the beginning of the message.
Mario Román (Feb 25 2026 at 15:57):Elena Di Lavore said:
Could we please have more details on the new proceedings track about teaching and communication?
As a PC member, I did not receive any information about this new route to publication. I am surprised that a decision that changes the scope of the proceedings was taken without consulting the community nor notifying the PC. Do we have an expert and diverse enough PC to cover the science of teaching? How do we evaluate teaching submissions against papers in applications of category theory?
I believe that the rest of the PC was not informed and never agreed to these changes. So I would like to initiate some open discussion about it.
Dear all,
Some of us have privately circulated and presented an open letter to the Steering Committee on this matter.
However, the Steering communicated to us that they decided that these proceedings—which were announced without the consent or previous consultation of the program committee—will still be submitted and reviewed at this conference and will be "published in a separate companion volume".
We want to ask for utmost respect for the work of the Steering and the work of the Chairs.
At this point, some of us may wish to stop serving this year's edition of the conference. We may feel that we have not been informed as honestly as possible when invited to serve to this conference; we may feel that teaching deserves to be valued more seriously than this; we may feel that the communication with the Program Committee is insufficient and lacking transparency; we may feel that it is unfair that the program committee and the broader community were never consulted; and we may feel that strong decisions about this edition of the conference have been imposed by a small subset of our community.
While keeping all due respect to all parties: We invite our colleagues at the Program Committee of ACT26 to reconsider if they wish to continue serving at ACT, at least during this year's edition.
We want to ask for utmost respect for any Program Committee member that wishes to stop serving ACT at least for this year. We ask that they are allowed to do so freely, without any kind of coercion or threat to their careers.
Respectfully,
Mario
Kevin Carlson (Feb 25 2026 at 18:04):John Baez said:
Two people on the PC are explicitly listed under "Teaching & Communication". Presumably they can evaluate papers in these fields. I doubt people who don't want to referee such papers will be forced to. (I certainly hope not!)
I'd just add to this that, while there are now three people on the T&C committee, only one actively publishes in the field this subcommittee will be assessing submissions in, as far as I can tell.