Niles Johnson

Working in topology and category theory
Professor, Ohio State at Newark

pronouns: he/him
website: https://nilesjohnson.net
bookwyrm: https://bookwyrm.social/user/qevreg

Last Notes

2026-10-09 18:26:02 GMT

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same! That's [job] security by obscurity.

2026-09-24 17:39:26 GMT

On the topic of math(s) infrastructure, and community, my periodic calendar reminder to donate to mathstodon just came up! The admin team here is doing such an awesome job that we mostly don't have to notice it; I'm very grateful for their work.
If you are able, and haven't done so recently, this could be your reminder too :) There's a donation link on their finance page:
https://wiki.mathstodon.xyz/finance
(And, if you're on a different instance, then consider donating there instead ;)

2026-09-11 21:44:10 GMT

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> i want to believe this can evolve into something more decisive
I would be glad to see that happen. I would never want to take away someone else's optimism, so instead I'll just say let's see what happens. In the meantime, maybe there's a way to refocus on the parts of math that are actually good and enjoyable.

2026-09-11 20:52:25 GMT

I don't know, the new statement seems like a lot of words to say we never thought the leopards would eat *our* faces.

2026-08-15 19:42:32 GMT

I wonder if the LLM people will get tired of mathematics if they run out of famous conjectures for the headlines.

2026-08-09 00:13:12 GMT

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yeah, I definitely missed that part :/

2026-08-08 13:39:42 GMT

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ha, yeah changes from referee comments were a begrudging improvement in my case too, and are in the arxiv version. Copy-editor changes included a bunch of font/notation changes that are worse, and are not in the arxiv version; we reversed some but not others. (Also, this is from that same Paré issue, but no one has yet forced us to put a disclaimer, and I'm not inclined to investigate.)

2026-08-08 13:24:35 GMT

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Also, in my experience, the "post-submission improvements or corrections" may be strictly negative in value.

2025-08-26 19:59:11 GMT

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Note, however, the comment there:
> ...That it works is because thmtools has its own internal way of handling different theorems types sharing the same counter (it calls them "siblings"). So cleveref was built to detect whether thmtools was loaded or not, and chance strategy accordingly. But beware: thmtools is not fully compatible with amsthm syntax (there are some edge cases), and there are also situations where thmtools break cleveref (I think the bugs I found were all fixed, but there may be more). So this is a best a bandaid that may cause pain down the road. –
Willie Wong
Commented Mar 14 at 13:12
I don't think this is just FUD; this earlier comment [1] on a different issue with cleveref points to future problems:
> ...The concrete culprit are changes in latex + hyperref: for the tagging project we need to move the hyperref functionality into the kernel and this requires to clean up patches in hyperref. In the newest latex \refstepcounter has been extended and hyperref patches have been removed. Sadly cleveref contains lots of patches and they now start to fall apart, but the maintainer is not responding. See e.g. tex.stackexchange.com/q/711418/2388 –
Ulrike Fischer
Commented Nov 6, 2024 at 8:35
[1] https://tex.stackexchange.com/questions/730153/algorithm2e-hyperref-cleveref-algorithms-lines-are-not-numbered-referenced/730188#comment1818295_730188
@npub14a5…9fse @npub1lez…3yeq @npub1nf4…nqe4 [@de_Jong_Tom](https://mathstodon.xyz/@de_Jong_Tom )

2024-12-12 00:56:13 GMT

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that's fantastic, and thanks!! I'll be happy to send it to you :)

2024-12-11 20:29:20 GMT

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Here is the table of contents for Volume III. Check it out (along with the full electronic version, above) and think about whether you would have use for a physical copy.
Volume III. From Categories to Structured Ring Spectra
Part 1. Enriched Monoidal Categories and Multicategories
Chapter 1. Enriched Monoidal Categories
Chapter 2. Change of Enrichment
Chapter 3. Self-Enrichment and Enriched Yoneda
Chapter 4. Pointed Objects, Smash Products, and Pointed Homs
Chapter 5. Multicategories
Chapter 6. Enriched Multicategories
Part 2. Algebraic K-Theory
Chapter 7. Homotopy Theory Background
Chapter 8. Segal K-Theory of Permutative Categories
Chapter 9. Categories of G∗-Objects
Chapter 10. Elmendorf-Mandell K-Theory of Permutative Categories
Chapter 11. K-Theory of Ring and Bipermutative Categories
Chapter 12. K-Theory of Braided Ring Categories
Chapter 13. K-Theory of En-Monoidal Categories
Bibliography and Indices
Appendix A. Open Questions
Bibliography
List of Main Facts
List of Notations
Index

2024-12-11 20:29:03 GMT

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The review and publication process has taken over three years, and I'm very happy to see it done :)
Details/requests:
- For this one, I'm willing to ship anywhere! If you're outside the continental US, please consider (a) whether it's really worth it and (b) a donation amount that will at least be comparable to the shipping cost.
- I know that you can make a fake donation receipt; don't be lame!
- I think the potential audience for this book is pretty small, so don't be shy if you think there's more than 0% chance you'll use it!
- The electronic version remains freely available thanks to a special agreement with the publisher (American Mathematical Society). So, thanks to them for agreeing with us! (And slight shame on them for making it a special, not standard, part of their publishing agreements.)
- Please boost this post! Also feel free to share it any other place you think people will be interested. I really don't know whether I can find five people who are interested enough to get this, but I hope so 😃

2024-12-11 20:27:14 GMT

🤔📚 Does anyone want a copy of this book?! 📚🤔
This is the third of three volumes about ring categories (En-monoidal categories). It has lots of extra stuff about enriched categories, multicategories, and K-theory machinery. I have five extra copies from the publisher, and I'd like to send them to people for whom they will be useful.
⚡⚡NOTE⚡⚡ If you just want access to the content, all three volumes are available for download here:
🔖 https://nilesjohnson.net/drafts/Johnson_Yau_ring_categories.pdf
I wrote a social media announcement in 2021 when we finished the writing, and that's here:
🧵 https://nilesjohnson.net/social/En-monoidal-book.html
If you *do* want a physical copy, here's what I propose: make a donation you think is appropriate to your local mastodon instance, like this one:
https://ko-fi.com/mathstodon
Then, send me a picture of the receipt, along with your mailing address via a DM here, or my email (nilesj at gmail). I'll wait roughly a week to see how many people take me up on this, and then I'll ship them out.
See details in the next post.
https://media.mathstodon.xyz/media_attachments/files/113/636/017/363/582/847/original/6a0a97d0ada551fe.jpg

2022-04-26 16:06:46 GMT

I appreciate the #introduction posts that people are writing! But I don't like writing my own!! Anyway, I'll try.
I'm a research mathematician, interested in social media for both professional and recreational reasons. If you follow me, you'll see a mix of math and non-math.
Here are four pictures of things I've been involved in. I'll add a little more in a comment below.
https://media.mathstodon.xyz/media_attachments/files/108/199/164/050/021/690/original/500da8d5e9ea675d.png
https://media.mathstodon.xyz/media_attachments/files/108/199/165/738/627/221/original/e48b9c7134cba8c1.png
https://media.mathstodon.xyz/media_attachments/files/108/199/166/688/302/560/original/e1c33de92a208b89.png
https://media.mathstodon.xyz/media_attachments/files/108/199/167/976/245/530/original/47af633878f3106e.png