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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.
Matteo Capucci (he/him) (Mar 03 2026 at 08:58):No other response from the steering commit?
Chad Nester (Mar 03 2026 at 09:10):Personally, I don't think this passes the sniff test.
Chad Nester (Mar 03 2026 at 09:12):I would like the conference to succeed in the long term, and for it to become a respectable publication venue for our community. I think this sort of thing undermines these goals.
Chad Nester (Mar 03 2026 at 09:15):I encourage anyone who shares my concerns to sign the open letter. While nothing seems likely to come of it in the short term, if enough people sign it we can use it to initiate a conversation about this at the conference itself this summer.
John Baez (Mar 04 2026 at 22:16):The Steering Committee has been talking about this with anyone who emails us for quite some time now. Recently one committee member emailed Barbara Konig and Matteo Mattuci and asked if the latest plan alleviates their previously voiced concerns. Barbara said it did while Matteo said he still had some concerns (which he listed; he can do it again here if he wants).
The latest plan is to have three volumes:
Since the call for papers has already gone out, and the committees to review papers have already been constituted, I think the most reasonable course of action is to not try to suddenly change everything now, but instead keep discussing these issues to decide how things should work for ACT2027.
One problem is that some people with objections to the idea of publishing papers about teaching and communication are talking here, but people who support this idea (like the Program Committee Chairs, and the Steering Commitee) are mainly communicating somewhere else: by email.
Discussions here are fine as far as they go, but as far as I can tell, nobody on the Steering Committee but me regularly reads this Zulip.
I've already tried to assuage this problem by pointing the other Steering Committee members to the conversation here. I'll do it again, and also point out the open letter. However I do recommend that people with concerns email the Steering Committee and especially discuss this at the business meeting at ACT2026: that's a meeting specially designed for discussing the future of the ACT conference.
Just so there's no mystery about it, the Steering Committee is
Nathanael Arkor (Mar 05 2026 at 06:11):Are "extended research proceedings" the combination of the research and teaching proceedings, or something else?
Nathanael Arkor (Mar 05 2026 at 06:12):(If the former, I'm wondering why everything would need to be published twice, in addition to how teaching is relevant to the stated aims of compositionality, but perhaps I'm misunderstanding.)
John Baez (Mar 05 2026 at 06:20):I think the idea is that while initial submissions of research papers to ACT2026 have a rather tight page limit (12 pages), and EPTCS will publish those submissions that are accepted, authors of some of the best papers will be invited to write longer "extended" papers to submit to Compositionality, to be refereed again there.
Nathanael Arkor (Mar 05 2026 at 07:54):Would that function any differently from the authors choosing to submit papers to Compositionality independently?
Jules Hedges (Mar 05 2026 at 11:27):John Baez said:
Discussions here are fine as far as they go, but as far as I can tell, nobody on the Steering Committee but me regularly reads this Zulip.
May I suggest that this is a problem? This platform seems to be where the majority of the ACT community talk to each other, it feels like the steering committee might be disjoint to the majority of the actual community they serve
Mario Román (Mar 05 2026 at 11:59):John Baez said:
One problem is that some people with objections to the idea of publishing papers about teaching and communication are talking here, but people who support this idea (like the Program Committee Chairs, and the Steering Commitee) are mainly communicating somewhere else: by email.
Respectfully, I think this is a mischaracterization. People has objections to the idea of creating, without the consent of the PC, ad-hoc proceedings tracks reviewed by a few non-necessarily experts. And people have been explaining the problem since October 2025 by email.
Ralph Sarkis (Mar 05 2026 at 12:15):After communicating this letter to the Steering committee, we got two answers. The first was completely dismissive of our concerns. It only argued that pedagogy is an important part of research, even if we had clearly stated our agreement with this point. It was also not very nice.
The second answer clearly stated the intent of separating the proceedings, but it did not discuss our concerns, and seemed to try to refute our (verifiable) claim that the PC was not consulted.
That did not invite further communication with the committee. Your message is more inviting.
Could you (=committee) be more transparent about the decision?
For example, what made you change your mind about having only one proceedings? Which parts of the letter do you agree with, and which parts don't you agree with?
Can you give a more precise description of the kind of contributions you invite in this new track? If you can provide examples, that would help. What are the evaluation criteria that the specialized PC will use?
What do you expect the negative impact of cancelling the call for papers will be? Has anyone expressed intent in submitting to this track?
Elena Di Lavore (Mar 05 2026 at 13:39):but people who support this idea (like the Program Committee Chairs, and the Steering Commitee) are mainly communicating somewhere else
In addition to answering the questions above, could you please communicate here any argument that supports having a separate teaching and communication proceedings reviewed by a parallel PC of three members? or, at least, communicate these arguments to the PC members?
Pawel Sobocinski (Mar 05 2026 at 14:23):I've stayed out of this conversation until now, but let me add my 2 cents.
I'm really disappointed by how this issue has been handled. We are still a relatively new community and these sorts of heated controversies don't help.
I think the PC chairs should have had a proper engagement with their PC, instead of using the SC as some kind of stick to beat the rest of the PC with. I've never seen anything like this in 20+ years of being on PCs, SCs and organising/hosting conferences: normally these are very collegial affairs with everyone doing their best to ensure the best outcomes.
I don't want to get personal, but I guess that this is due to the inexperience of some of the people involved, but also due to mixing different academic traditions -- certainly maths conferences are less formal events that do not carry (and are not expected to carry) the same prestige as top CS conferences. But prestige is important for younger researchers who need to establish themselves and strengthen their CVs. And, unfortunately, ACT has not thus far been doing a good job of establishing itself as a quality venue -- at least based on what I've been hearing from various people in my own network. We don't want to end up in a situation where an ACT paper is a CV red flag, like an MDPI paper or IEEE Access.
To get to the controversy itself: I still don't understand why there needs to be a published volume of T&C contributions -- the way I understood the initial idea was that the role of the additional three person PC was to curate a T&S conference session based on submitted abstracts/short papers where these topics could be discussed in the community: best practices, success stories, etc. I think this would be both a fun thing to attend and a valuable opportunity to discuss more meta aspects of our work. A few talks, maybe a panel.
What is and what is not written in the original CFP is not that important imo -- plans change all the time. The number of people affected is, I assume, extremely small anyway: who knows how many submissions this T&C track will attract? 2-3?
If publication is really an issue for somebody, a compromise we have also discussed within our group in Tallinn could be to kick the publication arrangements into the future (e.g. a special issue of some Mathematics education journal edited by the PC chairs) if the quality of the submissions merits it.
John Baez (Mar 05 2026 at 18:09):Nathanael Arkor said:
Would that function any differently from the authors choosing to submit papers to Compositionality independently?
This plan would produce a volume of Compositionality called something like "Proceedings of ACT2026". Journals often have special issues devoted to conference proceedings, and this would be like that. That's all I know.
For those who haven't been following the drama:
For several years there has been a heated argument involving many people about whether the conference proceedings of ACT should be published in Compositionality. Originally the plan was to do this, but some editors of Compositionality argued that it would lower the standards of that journal, because the review process suitable for a 12-page talk are - so they argued - lower than those of a typical paper in Compositionality. The people making this argument were mainly mathematicians, who generally don't take conference proceedings seriously. On the flip side of the argument were mainly computer scientists, who often take conference proceedings very seriously. I see the whole argument as arising from how applied category theory blends different academic cultures.
For the last couple of years, the people against publishing proceedings in Compositionality had won, and the proceedings were published in Electronic Proceedings of Computer Science.
In the new plan, anyone whose 12-page research abstract gets accepted for ACT2026 gets to publish in ETPCS, as before, but also the program chairs will choose some of the best papers and nominate them to be expanded and turned into papers that would be submitted to Compositionality.
I believe this plan is an attempt to compromise between warring factions, and that accounts for its rather ungainly nature. Perhaps this issue should be decided by a large tag-team wrestling match at the business meeting of ACT2026.
John Baez (Mar 05 2026 at 18:14):Jules Hedges said:
John Baez said:
Discussions here are fine as far as they go, but as far as I can tell, nobody on the Steering Committee but me regularly reads this Zulip.
May I suggest that this is a problem? This platform seems to be where the majority of the ACT community talk to each other, it feels like the steering committee might be disjoint to the majority of the actual community they serve
I actually don't think this is the platform where the majority of the ACT community talk to each other. Maybe it was once. But very few of the people working at Topos, Topos UK, the Safeguarded AI project post here any more. Those are three of the main employers of applied category theorists!
For example Brendan Fong and David Spivak and David Jaz Myers and Sophie Libkind never post here anymore, and I haven't seen you here for about a year. Mike Shulman used to post here a lot, and a bunch of trans people seem to left the forum for that reason. But Mike, too, hasn't posted here much since December.
My guess is that many people of these people are too busy, and have enough people to talk to already.
(Of course, I can't tell if people who is reading but not posting, or posting in private channels here. For example there's a research team including @Nathaniel Osgood, @ww, @Xiaoyan Li, @Kris Brown, @Evan Patterson and myself who a lot in a private channel here. I'd prefer that all this was public, because the main reason for it being private is simply that it might bore other people... but I like doing things in public more than 99% of people.)
John Baez (Mar 05 2026 at 18:30):As a result, I don't know any public forum where most of the people who go to the ACT conference can be expected to be present for discussions regarding this conference.
John Baez (Mar 05 2026 at 18:38):Ralph Sarkis said:
Could you (=committee) be more transparent about the decision?
You just asked 6 questions, not counting the above one:
For example, what made you change your mind about having only one proceedings? Which parts of the letter do you agree with, and which parts don't you agree with?
Can you give a more precise description of the kind of contributions you invite in this new track? If you can provide examples, that would help. What are the evaluation criteria that the specialized PC will use?
What do you expect the negative impact of cancelling the call for papers will be? Has anyone expressed intent in submitting to this track?
I can't really answer these questions on my own and say these are the committee's answers, since other committee members will have different opinions. The whole committee has to deliberate to produce official answers to question.
Nor do I volunteer for the job of taking these questions of yours, copying them into an email to the committee, discussing them, then reporting back here - and then repeating this process many times, because surely people here will have followup questions.
It's really better to email the whole committee at once. If you want I can provide all our email addresses. But it sounds like maybe you have them?
It's even better to do what I suggested earlier: have a discussion of this at ACT2026. As Pavel hinted, we probably wouldn't be having this problem if major decisions about the ACT conference proceedings were made at the business meeting.
David Spivak (Mar 06 2026 at 16:37):Hi all,
On Feb 24, we responded the following (below my signature) to Elena and Mario, and I supposed they would pass it on to the other signatories; I'm not sure if they did or not. I'm sorry I didn't post it here. I don't check this often, though I have now read through this thread. I understand that our response does not address every concern, nor were we aware of every potential solution, that has been discussed here. We continue to think about how we can best serve the community.
Best,
David
Dear Elena, Mario, (and other signatories),
Thank you for writing. Bob's comments [not included here] were his own and were not deliberated on by the larger committee. However, the steering committee has been actively deliberating this issue for the past week, and we communicated our decision to the PC chairs a few days ago.
The T&C session and submission process will continue as planned. However, T&C proceedings papers will be published in a separate companion volume rather than in the main research proceedings. We believe this is the structurally-correct approach: T&C papers and research papers serve different audiences and have different evaluation criteria, and a separate volume lets each stand on its own terms.
We want to be clear that we take the integrity of ACT proceedings seriously, and we appreciate that the signatories do as well. We also want to note that the PC chairs followed the process available to them—consulting the steering committee and notifying the full PC—and have been doing difficult, unpaid work on behalf of the community. We ask that everyone engage with them respectfully as they implement this adjustment.
For future years, the steering committee will establish a written policy requiring that new proceedings tracks receive full committee deliberation and PC consultation before the CFP is published.
Best,
David, on behalf of the ACT Steering Committee