Jordan Ellenberg
@jsellenberg.bsky.social
📤 3130
📥 156
📝 410
Mathematician, writer, Orioles fan, Wisconsinite, cargo shorts dad
quomodocumque.wordpress.com/2026/01/05/d...
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Dyadiku
I made a game. It’s like Sudoku but dyadic. It’s called Dyadiku. Try it! I’m very interested to see whether people find it playable and fun — in particular, does it admit a …
https://quomodocumque.wordpress.com/2026/01/05/dyadiku/
5 days ago
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quomodocumque.wordpress.com/2026/01/05/r...
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Reaching the masses (not a Marxist post)
Six popular math authors, including me, did a round-table interview for the Notices of the American Mathematical Society about talking about math to the non-academic public, or, as the Notices call…
https://quomodocumque.wordpress.com/2026/01/05/reaching-the-masses-not-a-marxist-post/
7 days ago
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quomodocumque.wordpress.com/2025/12/23/s...
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Self-portrait with about one quarter of Richard Serra’s sculpture Equal
Visit the post for more.
https://quomodocumque.wordpress.com/2025/12/23/self-portrait-with-about-one-quarter-of-richard-serras-sculpture-equal/
19 days ago
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quomodocumque.wordpress.com/2025/12/19/t...
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The American people have just one fixed idea
“The American people have just one fixed idea and, since that dominant thought is money, it follows that their spirit has a certain uniform and unpleasant dryness… prodigality is an unf…
https://quomodocumque.wordpress.com/2025/12/19/the-american-people-have-just-one-fixed-idea/
23 days ago
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quomodocumque.wordpress.com/2025/12/12/h...
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How I know zombies aren’t real
This piece of marketing doggerel from McDonald’s, concerning their Xmas-special Grinch meal, is the most foully defiling attempt to imitate Dr. Seuss’s verse I’ve ever encountered…
https://quomodocumque.wordpress.com/2025/12/12/how-i-know-zombies-arent-real/
30 days ago
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quomodocumque.wordpress.com/2025/12/03/a...
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Another example: sets of arcs and loops with bounded intersection
Yet another example of the kind of problem that falls under the sphere packing / cap set / Turan umbrella I blogged about last week. Let G be SL_2(Z) and H be upper triangular matrices. Then G/H is…
https://quomodocumque.wordpress.com/2025/12/03/another-example-sets-of-arcs-and-loops-with-bounded-intersection/
about 1 month ago
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quomodocumque.wordpress.com/2025/11/30/r...
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Random Americans, ethnic stereotypes, and large language models
I have been reading about the tendency of poll respondents to overestimate the size of small population subgroups (e.g. if you ask Americans what proportion of Americans are Jews, they’ll say…
https://quomodocumque.wordpress.com/2025/11/30/random-americans-ethnic-stereotypes-and-large-language-models/
about 1 month ago
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quomodocumque.wordpress.com/2025/11/27/n...
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“Not Vegan”
I saw a guy today wearing a hoodie that said “Not Vegan.” I’m not vegan either, not even close, but come on. This is like wearing a “Yankees Suck” shirt. I hate the Ya…
https://quomodocumque.wordpress.com/2025/11/27/not-vegan/
about 1 month ago
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quomodocumque.wordpress.com/2025/11/27/m...
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Mathgiving
Happy Thanksgiving to all my American readers, and hey, everyone else too — gratitude is global. In the US, this is the start of the season where people customarily think about their charitab…
https://quomodocumque.wordpress.com/2025/11/27/mathgiving/
about 2 months ago
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quomodocumque.wordpress.com/2025/11/24/s...
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Sphere packing, cap set, and the Turán problem are all the same thing
OK, they are not really the same thing. But I got you reading, right? Here’s the sense in which they’re all the same thing. Let G be a group and H < G a subgroup. Let m > 1 be an …
https://quomodocumque.wordpress.com/2025/11/24/sphere-packing-cap-set-and-the-turan-problem-are-all-the-same-thing/
about 2 months ago
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quomodocumque.wordpress.com/2025/11/08/l...
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Let us now praise United Airlines
I did manage to get home last night from Providence, despite widespread cancellations and delays caused by the government shutdown de-staffing air traffic control. United was speedy, flexible, and …
https://quomodocumque.wordpress.com/2025/11/08/let-us-now-praise-united-airlines/
2 months ago
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quomodocumque.wordpress.com/2025/11/07/i...
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I reviewed a book about the math foundations crisis for the New York Times
I thought the book had some interesting virtues but was also quite badly overwritten, and very confusing in its treatment of the mathematics. Here’s my review. For length reasons I wasn’…
https://quomodocumque.wordpress.com/2025/11/07/i-reviewed-a-book-about-the-math-foundations-crisis-for-the-new-york-times/
2 months ago
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I'm moderating an online discussion for the National Academies today, 3pm eastern, on math, risk management, and natural disasters!
www.nationalacademies.org/event/45862_...
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Risk Modeling and Management for Natural Disasters Innovation by the Numbers | National Academies
Learn more from the National Academies of Sciences, Engineering, and Medicine
https://www.nationalacademies.org/event/45862_10-2025_risk-modeling-and-management-for-natural-disasters-innovation-by-the-numbers
3 months ago
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quomodocumque.wordpress.com/2025/10/08/m...
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MacArthur Fellows: Wisconsin and Williams
The 2025 MacArthur Fellows have been announced, and I’m very pleased that two of the 22 awardees are my UW-Madision colleagues: congratulations to Ángel F. Adames Corraliza from atmospheric a…
https://quomodocumque.wordpress.com/2025/10/08/macarthur-fellows-wisconsin-and-williams/
3 months ago
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quomodocumque.wordpress.com/2025/09/30/c...
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Claudia Prieto, “Tus Ojos”
Claudia Prieto is a Venezuelan singer-songwriter about whom I know next to nothing except that she recorded this gorgeous song, “Tus Ojos,” in 2018. By the way, I found out about this s…
https://quomodocumque.wordpress.com/2025/09/30/claudia-prieto-tus-ojos/
3 months ago
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quomodocumque.wordpress.com/2025/10/03/t...
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Taylor Swift and Stephanie Burt, or: Life of a Harvard English Professor
It’s Taylor Swift album day! We listened to it last night at 11pm central when it went live. Snap reaction from AB, for whom 1989 is apex Swift and the last two albums have been too moody and…
https://quomodocumque.wordpress.com/2025/10/03/taylor-swift-and-stephanie-burt-or-life-of-a-harvard-english-professor/
3 months ago
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I gave a talk about machine learning and math
I, too, spoke at the CMSA Big Data conference where this cool math bio talk took place. If you’ve seen me give a talk about math and machine learning lately, you’ve seen some of the sli…
https://quomodocumque.wordpress.com/2025/09/26/i-gave-a-talk-about-machine-learning-and-math/
3 months ago
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Global epistasis emerges from a generic model of a complex trait (or: random walks on a hypercube with reweighting)
I still don’t really know what global epistasis is, but I really enjoyed Gautam Reddy’s talk about this paper at the CMSA Big Data conference two weeks ago. I’ll describe it, in c…
https://quomodocumque.wordpress.com/2025/09/21/global-epistasis-emerges-from-a-generic-model-of-a-complex-trait-or-random-walks-on-a-hypercube-with-reweighting/
3 months ago
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Mura Yakerson interviewed me
And we talked about math, writing, standup comedy, the art of interviewing (meta!) Mura’s whole channel is great. Bisi Agboola! Helene Esnault! Steve Strogatz! Mura’s mom! Check it out.
https://quomodocumque.wordpress.com/2025/09/19/mura-yakerson-interviewed-me/
3 months ago
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Klartag improves the sphere-packing constant
Hey! It escaped my notice until this week that Boaz Klartag has recently shown the existence of lattice sphere packings in dimension d of density at least c d^2 2^-d. This lower bound was stuck at …
https://quomodocumque.wordpress.com/2025/09/14/klartag-improves-the-sphere-packing-constant/
3 months ago
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To The Best of our Knowledge is finished
The longtime Wisconsin Public Radio show To The Best of Our Knowledge airs its last episode this weekend. You can listen to the stream at that link or you can listen to it over the airwaves tomorro…
https://quomodocumque.wordpress.com/2025/09/27/to-the-best-of-our-knowledge-is-finished/
4 months ago
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Predicament
I just learned that the origin of this word is “that which is predicated,” which is to say, more or less, any condition that can be described or specified, whether good, bad, or neutral…
https://quomodocumque.wordpress.com/2025/08/05/predicament/
4 months ago
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Still relevant: my interview in the Atlantic from Election Eve 2020, about epistemic humility, what probabilities really mean, and how not to freak out.
www.theatlantic.com/ideas/archiv...
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A Math Whiz on How to Stop Stressing About Election Forecasts
An interview with the mathematician Jordan Ellenberg about politics, election forecasting, and how to think about the future like a pro
https://www.theatlantic.com/ideas/archive/2020/11/election-probabilities-are-emotional-nonsense/616916/
about 1 year ago
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Philosophers of probability, your moment has arrived
about 1 year ago
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Somebody took the Harris for President sign off our lawn last night, but the joke is on them, the sign voted early
about 1 year ago
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It's corny I know but I do enjoy Maya Rudolph as Simulacramala.
about 1 year ago
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I actually picked up my landline and answered a poll the other day, so when you read that Harris is winning a stunning 100% of white men age 45-55 in Wisconsin, that's me
about 1 year ago
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Just thinking about actors whose names are close to old-timey adverbs. Charlize Thereon. Reese Whitherspoon. Chris Henceforth.
about 1 year ago
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Students in the UW system make up almost 3% of Wisconsin's population.
www.wmtv15news.com/2024/10/29/e...
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Enrollment inches upward in Universities of Wisconsin system
Overall enrollment in the Universities of Wisconsin system’s four-year schools ticked upward this fall compared with last year, data released Tuesday shows.
https://www.wmtv15news.com/2024/10/29/enrollment-inches-upward-universities-wisconsin-system/
about 1 year ago
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Really nice new paper by Canning, Larsen, Payne, and Willwacher which shows how far we've come in understanding unstable cohomology of M_g
arxiv.org/abs/2410.19913
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Moduli spaces of curves with polynomial point counts
We prove that the number of curves of a fixed genus g over finite fields is a polynomial function of the size of the field if and only if g is at most 8. Furthermore, we determine for each positive ge...
https://arxiv.org/abs/2410.19913
about 1 year ago
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You too, Politico? No. No! The districts you are talking about are not rural just because they are not in Madison or Milwaukee!
www.politico.com/news/2024/10...
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Have Democrats found a way to win over rural America? Look at what's happening in Wisconsin.
The party’s hot streak in statewide elections faces a crucial test in out-state districts long held by Republicans.
https://www.politico.com/news/2024/10/27/wisconsin-democrats-rural-voters-00185617
about 1 year ago
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Interview with my mom!
cancerhistoryproject.com/article/susa...
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Susan Ellenberg started out as a high school math teacher—then became a leading biostatistician
A mathematical puzzle fascinated Susan Ellenberg as a child. John is twice Mary’s age when John was Mary’s age. When Mary will be John’s age, the sum of their ages will be 63. How old are John
https://cancerhistoryproject.com/article/susan-ellenberg-high-school-teacher-to-leading-biostatistician/
about 1 year ago
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I used to have a car like that
add a skeleton here at some point
about 1 year ago
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Syllabus for Michael Harris's course on mathematics and the humanities:
www.math.columbia.edu/~harris/webs...
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Michael Harris | MATHEMATICS GU4200, Spring 2025 (page under construction)
Professor of Mathematics
https://www.math.columbia.edu/~harris/website/courses1/mathematics-gu4200-spring-2025
about 1 year ago
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Bad headline writing from the Chicago Tribune! The amendment would remove the constitutional guarantee of the right to vote that US citizens in Wisconsin currently enjoy.
www.chicagotribune.com/2024/10/19/w...
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Wisconsin voters consider constitutional amendment barring noncitizens from voting
Republican legislators are asking voters for permission to amend the state constitution to clearly prohibit foreign nationals from voting in any election held in the state.
https://www.chicagotribune.com/2024/10/19/wisconsin-constitutional-amendment/
about 1 year ago
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Somebody stole the pumpkin off our porch. Who does that??
about 1 year ago
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That’s that’s me gazpacho
about 1 year ago
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about 1 year ago
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Fewer, actually.
about 1 year ago
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This is cool from Kollar and Villalobos-Paz -- tons of affine cubic surfaces with infinite discrete automorphism group, didn't realize you could do this
arxiv.org/abs/2410.03934
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Cubic surfaces with infinite, discrete automorphism group
We prove that the automorphism group of an affine, cubic surface with equation $xyz=g(x,y)$ contains ${\mathbb Z}$ as a finite index subgroup. These equations were first studied by Mordell. v.2: small...
https://arxiv.org/abs/2410.03934
about 1 year ago
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Wisconsin! You can vote in-person starting TODAY! Get your vote in now and keep lines short on November 5. Put your address in myvote and it'll show you where and when you can vote.
myvote.wi.gov/en-us/Vote-A...
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Vote Absentee In Person
https://myvote.wi.gov/en-us/Vote-Absentee-In-Person
about 1 year ago
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I'm only following the NFL sporadically this year, but what problem is the new onside kick rule trying to solve?
about 1 year ago
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David Foster Wallace's cruise ship and state fair essays are wonderful, rich, and fully human pieces of work, but on the whole the current state of magazine writing would probably be better if they'd never been published.
about 1 year ago
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I just want to encourage you all to knock on doors encouraging people to vote and letting them know how they can vote early. You get a nice walk and a lot of friendly conversation.
about 1 year ago
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The phrase "Cams and euphrasia fill the Earth" was troubling me in a dream last night. I don't know what it means.
about 1 year ago
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Dead Milkmen fans everywhere shed a tear.
www.thedrive.com/news/thats-a...
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That's All, Folks: Chevy Camaro Production Officially Ends
The Bowtie's beloved muscle car is going away with no immediate successor in line.
https://www.thedrive.com/news/thats-all-folks-chevy-camaro-production-officially-ends
about 1 year ago
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I don't know why I have to keep telling the New York Times this but Baraboo is not rural!! It's a city! A small city!
www.nytimes.com/2024/10/14/u...
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In Rural Wisconsin, Race Is an Undercurrent of the Presidential Election
Former President Donald Trump’s recent attacks on his opponent could affect the vote. “It’s a stirring of the pot,” one voter said.
https://www.nytimes.com/2024/10/14/us/elections/election-race-issues-baraboo-wisconsin.html?unlocked_article_code=1.SE4.BIQS.UU99lmTON1uV&smid=url-share&fbclid=IwY2xjawF-m0tleHRuA2FlbQIxMQABHQGVhQqxoTMiFqVXIAluwnCvDXeA0L4fOT37EM46DSoOU3eb-ZwQm0MiKg_aem_lzJNr9D9qJy50LV7B2GbzA
about 1 year ago
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Man, New York Times recipe readers really just see the word "sheet pan" and smash like.
about 1 year ago
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Hey Milwaukee! I'm talking random walks and AI at UWM at 4pm today:
uwm.edu/letters-scie...
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From malaria to chatGPT: the birth and strange life of the random walk - Letters & Science
The Dean’s Distinguished Lecture in the Natural Sciences for 2024 features Professor Jordan S. Ellenberg from UW-Madison. The “random walk” is a mathematical concept which underlies the way scientists...
https://uwm.edu/letters-science/event/from-malaria-to-chatgpt-the-birth-and-strange-life-of-the-random-walk/
about 1 year ago
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I'll be live on the always entertaining In Lieu of Fun in a couple of hours, talking -- I'm not sure? Superstorms? AI? Your guess.
www.youtube.com/live/OVE-SDm...
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YouTube
Share your videos with friends, family, and the world
https://www.youtube.com/live/OVE-SDmEa5A
about 1 year ago
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