You're reading the public-facing archive of the Category Theory Zulip server.
To join the server you need an invite. Anybody can get an invite by contacting Matteo Capucci at name dot surname at gmail dot com.
For all things related to this archive refer to the same person.
Madeleine Birchfield (Jun 01 2025 at 22:03):Speaking of bad names, why is the category of assemblies called "Ass", i.e. in
https://ncatlab.org/nlab/show/realizability+topos
Patrick Nicodemus (Jun 01 2025 at 22:04):you also see that name for the set of associated primes
Madeleine Birchfield (Jun 01 2025 at 22:06):There's also the proof assistant [[Coq]] named after Thierry Coquand, which has rather unfortunate connotations in English.
Edit: i see that they have changed their name to Rocq now.
David Michael Roberts (Jun 01 2025 at 22:37):@Madeleine Birchfield also https://ncatlab.org/nlab/show/associative+operad
David Michael Roberts (Jun 01 2025 at 22:38):But thankfully the nLab seems to prefer the notation Assoc.
Nathanael Arkor (Jun 02 2025 at 01:39):Madeleine Birchfield said:
Speaking of bad names, why is the category of assemblies called "Ass", i.e. in
This is something I also never understood. "Asm" is clearer and avoids the issue, so seems better in every respect.
Mike Shulman (Jun 02 2025 at 02:45):The great thing about the nlab is that if there's something you don't like, you can do something about it.
Nathanael Arkor (Jun 02 2025 at 03:00):The problem isn't the nLab; it's the existing literature.
David Michael Roberts (Jun 02 2025 at 03:01):Well, I didn't like that certain folklore knowledge was missing, and it was summarily removed for not being backed up by literature. With my cynics hat on, I could bet that the neologism Asm would be frowned on without at least one published article to justify it. I would hope that instead the nLab could take a principled position in this case and be a catalyst for change.
Mike Shulman (Jun 02 2025 at 04:11):I feel sure that I've seen Asm in existing literature, but I don't have the time to try to track it down now.
I wasn't following the discussion of folklore but I thought I heard someone say that that position got moderated later. If that's still a problem I'm happy to go raise a stink -- the nLab should absolutely be a place for recording folklore.
Notification Bot (Jun 02 2025 at 04:12):10 messages were moved here from #practice: terminology & notation > the word "walking" in category theory by Mike Shulman.
Mike Shulman (Jun 02 2025 at 04:12):Nathanael Arkor said:
The problem isn't the nLab; it's the existing literature.
Oh, so "i.e." in the original message meant "e.g."? (-:O
Madeleine Birchfield (Jun 02 2025 at 04:34):Mike Shulman said:
Nathanael Arkor said:
The problem isn't the nLab; it's the existing literature.
Oh, so "i.e." in the original message meant "e.g."? (-:O
Perhaps? I personally just saw it on that nLab article and wasn't aware of its use in the existing literature, since this subfield isn't one that I read the literature on.
Mike Shulman (Jun 02 2025 at 04:45):Searching my directory of papers for assemblies the first hit is 1803.06649 which says
We shall denote by Asm the category of assemblies and morphisms of assemblies.
The second is 1404.6997 which says
We give simple characterizations of the category PAsm(A) of partitioned assemblies
The third is 1802.06400 which says
In loc.cit., the full subcategory Asm on the ¬¬-separated objects of Eff is also introduced and studied—those objects have later been christened “assemblies”, hence the shorthand Asm for the full subcategory they determine
Madeleine Birchfield (Jun 02 2025 at 04:57):Mike Shulman said:
The second is 1404.6997 which says
We give simple characterizations of the category PAsm(A) of partitioned assemblies
The Jonas Frey paper is already listed in the references at the bottom of [[realizability topos]].
Madeleine Birchfield (Jun 02 2025 at 05:00):But the other two references listed at the bottom of the page do indeed use "Ass" for the category.
Madeleine Birchfield (Jun 02 2025 at 05:03):Well if anybody wants to add the Maietti paper and the names "Asm" and "PAsm" to the article, they are free to do so. I won't today because I do have to sleep.
David Michael Roberts (Jun 02 2025 at 05:52):Thanks all for the detective work. I also can't do the edits right now, looking forward to the improvement. I vote for relegating the notation Ass to a footnote on the sentence introducing the notation Asm/Assoc/etc on their respective pages
Ryan Wisnesky (Jun 02 2025 at 07:43):heh, it was always fun to say "I do Hoare type theory using Coq" and on that note I can't help but mention the https://en.wikipedia.org/wiki/Cox–Zucker_machine
Morgan Rogers (he/him) (Jun 02 2025 at 07:46):The reason for Coq changing names was exactly people pushing that kind of joke. I'm glad it's changing.
Jonas Frey (Jun 02 2025 at 09:16):I've always used Asm, and I learned from (an earlier version of) Thomas Streicher's lecture notes.
Jonas Frey (Jun 02 2025 at 09:20):The first use of Asm that I can find is Lars Birkedal's thesis (which by the way uses an unusual definition of assemblies). Longley and Menni in the 90s used Ass.
Madeleine Birchfield (Jun 02 2025 at 17:43):David Michael Roberts said:
Madeleine Birchfield also https://ncatlab.org/nlab/show/associative+operad
Does the literature use "Ass" for the associative operad as well? The only reference listed in that article uses "Assoc", and I'm not familiar with the literature on monads / operads at all.
Mike Shulman (Jun 02 2025 at 19:00):I think I've seen Ass and Comm for the associative and commutative operads, but I don't have a specific reference in mind.
Amar Hadzihasanovic (Jun 02 2025 at 19:42):The symmetric operad of nonunital associative algebras is called Ass in the Loday-Vallette book "Algebraic operads".
David Michael Roberts (Jun 02 2025 at 19:45):@Madeleine Birchfield yes
David Michael Roberts (Jun 03 2025 at 07:10):Having a new page [[Ass]] seems like a step backwards....
David Michael Roberts (Jun 03 2025 at 07:13):If nothing else, disambiguating between [[associative operad]] and [[assembly]] is a strong argument for dropping 'Ass' as notation in favour of Assoc and Asm (and PAsm) respectively.
Madeleine Birchfield (Jun 03 2025 at 14:33):evil Ass = a category of assemblies that doesn't satisfy the principle of equivalence
fosco (Jun 03 2025 at 15:29):How did the conversation shift from "bad name because it doesn't convey a sufficiently clear idea of the concept defined" to "bad name because it's a not-so-covert dirty joke"?
fosco (Jun 03 2025 at 15:32):I understand I am in a minority, but (I am 12 and) I actually always enjoyed these puns. Can you ELI5 why are they so upsetting for people?
Madeleine Birchfield (Jun 03 2025 at 15:42):It's also just because it's a dirty joke in English that doesn't make sense in other languages. Like in Swiss German, "ass" means "ate".
Madeleine Birchfield (Jun 03 2025 at 15:43):But mathematics is written in English these days, so everything gets interpreted through the English language.
Madeleine Birchfield (Jun 03 2025 at 15:48):In addition, "ass" is mostly a North American phenomenon iirc and people elsewhere use "arse" instead. But because America dominates the world we all get exposed to American spelling conventions.
Mike Shulman (Jun 03 2025 at 16:06):fosco said:
How did the conversation shift from "bad name because it doesn't convey a sufficiently clear idea of the concept defined" to "bad name because it's a not-so-covert dirty joke"?
I thought the latter was already the original question.
Paolo Perrone (Jun 03 2025 at 16:22):fosco said:
I understand I am in a minority, but (I am 12 and) I actually always enjoyed these puns. Can you ELI5 why are they so upsetting for people?
Let me try to answer this. (I'm not attacking you or anyone, just trying to answer the question.)
My very personal opinion (as someone who can't stop making nerdy jokes, ask my colleagues...) is still to avoid any sexual, political or religious references when naming mathematical entities (and software, etc).
The reason is that we don't know who the audience will be. When we tell a joke to a group of friends, colleagues, etc, we more or less know what makes them laugh, what could trigger them, offend them, or what could simply not be funny. (If a friend of mine has just lost his mother, I'm not going to make a "yo momma" joke, right?) Of course not every joke lands perfectly, and some times things get awkward anyway, but we try. Now, this strategy, crucially, cannot possibly work when writing math or software.
The thing is, mathematics is so universal and cross-cultural that it's impossible to know the background, culture, and ideas of everyone who will study it, especially in the future. And references to sex, politics and religion are the most likely ones to land badly. (For an Italian-to-Italian example: think of a foreigner that comes to Italy and starts saying bestemmie left and right. Some will laugh, some will be offended, some might even start a fight, and there is no way for the foreigner to know in advance.)
The risk is that math that could have perfectly reached someone from a different background, instead fails, because:
This is of course not just limited to sex, politics and religion. The risk is always there. But these three are by far the most risky ones - it's just much easier to avoid those three altogehter. Or at least, that's my very personal opinion.
(And I assure you, even without these, I still have plenty of material for stupid jokes.)
daniel gratzer (Jun 03 2025 at 16:37):I think @Paolo Perrone has the right of it here (and I can confirm from my time at Oxford that he does make a lot of good nerdy jokes :) ).
I'll also just add that even jokes that are not about sensitive topics often fall flat very quickly in the context of naming mathematical objects or writing papers. They have to not just be funny to a very broad audience the first time, but also not become stale or irritating after 20 rereads of a paper or 200 references to the object. I've often had the issue that a paper with a funny title was legitimately funny and clever the first time I read it, but then really became annoying when I realized I couldn't search for it as it had no relevant keywords in the title...
Madeleine Birchfield (Jun 03 2025 at 16:37):Paolo Perrone said:
- (ironically, that's what seems to be happening with homology in the US under Trump);
Right, because "homo" in recent years has become a synonym of "gay" so "homology" can now be interpreted as "the study of gay people". And then it's understandable why it might be controversial in the United States.
Madeleine Birchfield (Jun 03 2025 at 16:45):And that ruins a whole lot of other words used in mathematics. Is a "homotopy" a place for gay people?
Madeleine Birchfield (Jun 03 2025 at 17:04):Paolo Perrone said:
- Or more pragmatically, the name is so distracting that, every time the concept is approached, the conversation just ends up turning into a series of jokes (or, worse, into a political discussion). Maybe engaging, but such a waste of brain power! The thing is, we are human, and for as much as we may love math, things like "Ass" or "Fascist" or "Hell" will still draw our attention away from things like "Let's see if this epsilon depends not only on delta, but also on x".
This is true elsewhere in life. A number of small towns in Germany and Austria changed their names from "Fucking" to "Fugging" because of the English word "fuck".
Paolo Perrone (Jun 03 2025 at 18:59):Madeleine Birchfield said:
Paolo Perrone said:
- Or more pragmatically, the name is so distracting that, every time the concept is approached, the conversation just ends up turning into a series of jokes (or, worse, into a political discussion). Maybe engaging, but such a waste of brain power! The thing is, we are human, and for as much as we may love math, things like "Ass" or "Fascist" or "Hell" will still draw our attention away from things like "Let's see if this epsilon depends not only on delta, but also on x".
This is true elsewhere in life. A number of small towns in Germany and Austria changed their names from "Fucking" to "Fugging" because of the English word "fuck".
Speaking of German, it has this word, inhaltlich, which as a scientist I find wonderful. I wish English had a word which one could use in the same way. ("On-topic" or "pertaining to the content" are close translations, but they are not used in the same way, and are not nearly used as casually or frequently as in German.) So basically what I was saying above is that a name like "Ass" turns a discussion from inhaltlich into uninhaltlich. And to me, that's exactly the end of mathematics.
Madeleine Birchfield (Jun 03 2025 at 19:11):When calqued to English "inhaltlich" becomes "contently", but that word has a different meaning in English; it's an adverb meaning "in a satisfied manner".
Ryan Wisnesky (Jun 03 2025 at 20:12):I understand "ChatGPT" is crass in French when pronounced naively (google for details)
Joe Moeller (Jun 03 2025 at 21:16):Paolo Perrone said:
Madeleine Birchfield said:
Paolo Perrone said:
- Or more pragmatically, the name is so distracting that, every time the concept is approached, the conversation just ends up turning into a series of jokes (or, worse, into a political discussion). Maybe engaging, but such a waste of brain power! The thing is, we are human, and for as much as we may love math, things like "Ass" or "Fascist" or "Hell" will still draw our attention away from things like "Let's see if this epsilon depends not only on delta, but also on x".
This is true elsewhere in life. A number of small towns in Germany and Austria changed their names from "Fucking" to "Fugging" because of the English word "fuck".
Speaking of German, it has this word, inhaltlich, which as a scientist I find wonderful. I wish English had a word which one could use in the same way. ("On-topic" or "pertaining to the content" are close translations, but they are not used in the same way, and are not nearly used as casually or frequently as in German.) So basically what I was saying above is that a name like "Ass" turns a discussion from inhaltlich into uninhaltlich. And to me, that's exactly the end of mathematics.
Would "salient" or "relevant" be good translations?
Paolo Perrone (Jun 03 2025 at 21:43):Maybe "relevant", but without the judgemental aspect. (But we should ask a native speaker.)
David Michael Roberts (Jun 03 2025 at 22:28):The parent discussion was triggered b6 sudden nLab purism for being all grown up and not having a little fun, which I find less harmful than having a nLab page whose title is an outright off-colour joke, even when the latter appears in the literature.
The 'final exam' attributed to "Phreilambud" in a CT Springer lecture notes volume is a good example of off jokes aging badly, even if some of them are still funny and nerdy (prove Mac Lane's theorem that all diagrams commute)
Madeleine Birchfield (Jun 03 2025 at 22:38):For context, this was the original nForum discussion, about the name 'baby Elephant' for Johnstone's [[Topos Theory]]:
https://nforum.ncatlab.org/discussion/11642/topos-theory/?Focus=122342#Comment_122342
Madeleine Birchfield (Jun 03 2025 at 22:46):Now there's a newly created disambiguation page titled [[Ass]], and an edit war over whether or not there should be a note on [[Ass]], [[assembly]], and [[associative operad]] saying that the use of "Ass" should be discouraged on the nLab.
https://nforum.ncatlab.org/discussion/19300/ass/#Item_0
https://nforum.ncatlab.org/discussion/19305/assembly/#Item_0
Madeleine Birchfield (Jun 03 2025 at 23:37):Maybe this is a topic for the nLab's steering committee to handle @David Corfield @Toby Bartels @Todd Trimble
Todd Trimble (Jun 04 2025 at 00:18):FWIW, the pages [[assembly]] and [[associative operad]] look unobjectionable to me.
The page [[Ass]] calls attention to itself quite needlessly IMO. My own inclination would be to remove it.
There was a point in time when the nLab had a very busy editor whom we finally asked to stop; during that time I was prompted to start the article [[writing in the nLab]]. I'm going to quote something I think is relevant:
Unless you are supremely confident in your expository skills, the advice if you are a newcomer is generally to write straight mathematics ... Anything that distracts or deflects the reader’s attention or any unnecessary digression is, in mathematical writing, generally bad.
I would say the article [[Ass]] is a distraction. In contrast, the quick citation in passing of the abbreviation Ass on the [[assembly]] page is appropriate and does not cause undue attention to itself. Nothing more needs to be said on the matter, outside of the nForum (which is where I think policy discussions generally belong).
David Michael Roberts (Jun 04 2025 at 02:06):The secondary issue is a user whose name I do not recognise, without an nForum account, said we should wait for a pronouncement from Urs as to what happens next. This seems to me a weird thing, and shows evidence one of a couple of imho undesirable things.
Todd Trimble (Jun 04 2025 at 02:46):David Michael Roberts said:
The secondary issue is a user whose name I do not recognise, without an nForum account, said we should wait for a pronouncement from Urs as to what happens next. This seems to me a weird thing, and shows evidence one of a couple of imho undesirable things.
Yes, quite. It's a really uncomfortable situation.
David Michael Roberts (Jun 04 2025 at 03:01):There's also the Adams Spectral Sequence, leading to a third object sometimes called ASS https://nforum.ncatlab.org/discussion/5456/adams-spectral-sequence/#Item_29 now edited it seems.
Nothing wrong with Adams SS as a shortening, should one need it
Madeleine Birchfield (Jun 04 2025 at 03:42):Maybe we should talk about this topic on the nForum, as suggested by Mike Shulman:
Perhaps it is a more general problem that people are going to Zulip instead of here to talk about the nLab, and then coming to the nLab to make an edit based on that discussion, but then it seems to come out of nowhere to people here who weren’t on Zulip.
Madeleine Birchfield (Jun 04 2025 at 04:05):Todd Trimble said:
There was a point in time when the nLab had a very busy editor whom we finally asked to stop; during that time I was prompted to start the article [[writing in the nLab]]. I'm going to quote something I think is relevant:
That article is somewhat out of date. People cannot edit under the name "Anonymous" on the nLab anymore, so remark 1.1 isn't true anymore.
Todd Trimble (Jun 04 2025 at 04:38):Feel free to edit.
David Corfield (Jun 04 2025 at 06:26):One of the advantages of living in an English-speaking country where 'ass' just means donkey.
Matteo Capucci (he/him) (Jun 04 2025 at 11:17):There's a certain self-fulfilling prophecy in hunting down these unfortunate names, namely that then people can't help but address them... I remember someone giving an informal talk once, involving the double powerset monad... PP. People were fine until someone audibly laughed, at which point the spell dissolved, we all became aware of the ambiguity and couldn't help but laugh at the silliness of the situation.
IMO it's good to try and avoid awkward terminology when possible, but we can also just be adults and, the same way you don't laugh in your doctor's face if they mention genitals, we can keep it together if someone abbreviates associativity to 'ass'...
Todd Trimble (Jun 04 2025 at 12:25):People often write for a projection operator, which is idempotent, and therefore , and now you can't unhear that.
In any case, while I won't completely lose my shit if I see Ass, I will always actively despise it as a mathematical abbreviation.
Madeleine Birchfield (Jun 04 2025 at 12:31):David Michael Roberts said:
Nothing wrong with Adams SS as a shortening, should one need it
SS has Nazi connotations.
Madeleine Birchfield (Jun 04 2025 at 12:37):Matteo Capucci (he/him) said:
There's a certain self-fulfilling prophecy in hunting down these unfortunate names, namely that then people can't help but address them...
Personally for me, I randomly stumbled upon "Ass" while reading the article on [[realizability toposes]] in search of examples of toposes with a global sections functor, and just commented on the state of affairs on the previous thread dedicated to bad names. I didn't expect this subject to be broken out into its own topic and to develop in the direction it did.
Madeleine Birchfield (Jun 04 2025 at 12:40):David Corfield said:
One of the advantages of living in an English-speaking country where 'ass' just means donkey.
The category of donkeys.
David Michael Roberts (Jun 04 2025 at 12:42):@Madeleine Birchfield (first message) - well yes, and it was much more tone deaf with Mochizuki was referring to his German colleagues Scholze and Stix, with whom he had a big disagreement, as 'SS'.
But a historical acronym is less obvious than a common word in US parlance. I do know about the SS, but it didn't even occur to me in writing that. I find it hard to believe that the US mathematicians who wrote ASS were not aware of what they were writing, though.
Madeleine Birchfield (Jun 04 2025 at 12:47):I don't really get how "Ass" in the UK any less of a bad name than stuff like "evil". Yes, it doesn't have the same connotations it does in North America, but people are still going to be distracted talking about the non-mathematical common definition, whether it be donkeys or morality.
Todd Trimble (Jun 04 2025 at 14:02):David Michael Roberts said:
Madeleine Birchfield (first message) - well yes, and it was much more tone deaf with Mochizuki was referring to his German colleagues Scholze and Stix, with whom he had a big disagreement, as 'SS'.
But a historical acronym is less obvious than a common word in US parlance. I do know about the SS, but it didn't even occur to me in writing that. I find it hard to believe that the US mathematicians who wrote ASS were not aware of what they were writing, though.
I also wouldn't have noticed SS here. But with regard to ASS, words from the lead-in to Sir Mix-a-Lot's Baby Got Back seem a propos: "it's like, out there".
There was an n-Category Cafe post, Mathematical Emotion by David Corfield, with a whole bunch of such discussion. One of the comment threads, concerning "ass", was started by Urs, and developed into a long and emotional conversation. [Elsewhere under David's post, someone began to complain about "bra" (appearing in bra-ket, and also in "algebra", now that I think of it) and "cleavage" (as it relates to fibrations).] I bring this up mainly because Toby argued for why "Ass" should be considered okay for general use.
Obviously I didn't agree, but I generally advocate gentle persuasion and an appeal to reasonableness over outright censorship.