
Tweets about algebra, number theory, and miscellaneous math by @JohnDCook.
Joined January 2010
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Algebra Etc. retweeted
I have a truly marvelous Lean certificate for this proposition which this context-window is too narrow to contain.
Algebra Etc. retweeted
The largest math proof in human history is now computer-verified.
Today, Axiom announces a complete Lean auto-formalization of the Classification of Finite Simple Groups, the "periodic table of symmetry."
About 15,000 pages, built by over 100 mathematicians across generations.
Algebra Etc. retweeted
For 130 years we only knew the zeros of the Riemann zeta function sit somewhere strictly between 0 and 1.
Now, a proof has squeezed every one of them into the band from 1/8 to 7/8.
Most of what the full Riemann hypothesis would tell us about the primes already follows from that, and the proof needed no new ideas, just old tools everyone thought were too weak.
See below for link
Algebra Etc. retweeted
Believe it or not, America's 5 largest cities lie perfectly on a 4th-degree polynomial
Algebra Etc. retweeted
As any set of four element is unique up to bijection, we are justified in calling the set E={Earth, Fire, Air, Water} the four elements
Algebra Etc. retweeted
It's interesting to think about how much, if at all, the positive sentiments expressed here are appropriate to mathematicians. His main reason for optimism comes at the end: that now that "chiselling code by hand" is no longer necessary, "we can build amazing things". 1/3
Algebra Etc. retweeted
Apparently every theorem can be proved just with linear algebra? Absolute W for representation theorists.
Algebra Etc. retweeted
Learning how to read analog clocks teaches students more than just how to use a technology that has become less common.
Algebra Etc. retweeted
Contest problems contain a trick, and AI may be very good at discovering the trick.
That's very different from solving real world problems.
Closed-world vs open-world. Kind problems vs wicked problems.
nitter.cf/normonics/status/20976…
Algebra Etc. retweeted
Latest comment on my blog post on efficiently computing a lower bound on the rank of a matrix:
"Thank you for being beacon of hope during uncertain times"
I'm glad the rank-trace theorem gives people hope.
Algebra Etc. retweeted
Two weeks ago, Rikhav Shah and I posted a preprint on the growth factor in Gaussian elimination, and settled a very old problem. It turns out complete pivoting and rook pivoting have quasi-polynomial growth. I’ve spent a decade thinking about this problem. math.mit.edu/~urschel/prepri…
Algebra Etc. retweeted
"I teach mathematics at UC Berkeley. Three days a week, I stand in front of lecture halls with 500 to 1,400 students. By the second week of the semester, I already know who is in trouble. Some students are five to eight years behind in mathematics. Office hours that should be spent discussing integrals instead become lessons on fractions and basic algebra you would expect students to learn in middle school." sfstandard.com/opinion/2026/…
Algebra Etc. retweeted
It's funny that the Riemann hypothesis is now a competition between Anthropic and OpenAI to better market their B2B SaaS offerings
We asked an unreleased research version of Claude to take a stab at the Riemann hypothesis.
It didn’t solve it, but it did make strides on a related problem: it increased the lower bound for the fraction of zeros of the Riemann zeta function that satisfy the hypothesis from 41.6% to 67.2%.
anthropic.com/research/riema…
Algebra Etc. retweeted
Ramanujan claimed to have taught himself math using Carr’s “Synopsis of Results in Pure & Applied Mathematics” which is unique in its emphasis of continued fractions.
Do you know what Hardy judged Ramanujan’s “formal command of” to be unmatched by anyone in the world? (hint: they are used exhaustively in much of his most brilliant work)
You guessed it!
Continued fractions.
Similarly, Feynman was given Woods’s “Advanced Calculus” in high school, which taught the unpopular trick of differentiating under the integral sign. he explicitly credited Woods with giving him a “different box of tools” that helped him solve problems that others found difficult (if you’ve ever done math competitively you probably know differentiating under the integral sign as the “Feynman trick”.)
I should have mentioned Grothendieck:
As a broke stateless teenager with a sick mother and a dead father at the University of Montpelier, Alexander Grothendieck (by his own account) could not find any textbooks that gave satisfactory definitions of length, area, and volume. Unsatisfied, he worked entirely alone for years developing a “general theory of integration”.
When he arrived in Paris in 1948 and handed the manuscripts around the (probably very amused) Cartan circle, he learned that he had spent years rediscovering the then half-century old Lebesgue integration, which was not by any means cutting edge, and in fact standard material in Paris. It was, in other words, totally worthless.
Interestingly though, his retrospective view of these solitary years (what he called his “années cruciales”) was that they were the most formative of his mathematical life.
He writes incessantly about the importance of this kind of solitude in ReS, and gives a beautiful “heirs and builders” analogy, which is very similar to the “bag of tools” analogy of Feynman. In those years, he writes, he “learned to approach the things which [he wanted] to know with [his] own eyes.”
Moreso than Feynman and Ramanujan, Grothendieck lived under an extreme kind of intellectual solitude which begat a unique view of and approach to mathematics. It is intuitive that a unique view of mathematics will create unique mathematical work, but it is not exactly intuitive that a unique view of math is an inherently valuable one. But it is! Consider the integral trick: the integral trick was valuable because nobody knew about it. Some tools are valuable because nobody else uses them.
In Grothendieck’s words,
“It is within this solitary act, above all else, that ‘creation’ lies.”
(This insight runs deeper than mathematics but I’d consider it a deep betrayal to the spirit of Grothendieck to write about it)
Algebra Etc. retweeted
Enumerating rooted trees and non-overlapping circles
johndcook.com/blog/2026/08/0…
Algebra Etc. retweeted
Python has a built-in method to display floats in hex but not in binary.
How to use the former to accomplish the latter.
nitter.cf/CompSciFact/status/208…
π = 11.0010010000111111011010101...
johndcook.com/blog/2026/07/2…
Algebra Etc. retweeted
you come to me today, on the day i disprove the jacobian conjecture, and you ask me to center a div
Algebra Etc. retweeted
"Mathematical activity requires daily practice. If you stop for too long, the know-how erodes. The habits are lost. Fortunately, this is only temporary."
– Alain Connes (1947-)
#quote #mathematics #math #maths

































