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▲Hannah Cairo: 17-year-old teen refutes a math conjecture proposed 40 years agoenglish.elpais.com
245 points by leephillips 5 hours ago | 36 comments
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marvinborner 2 hours ago [-]
There's a video by Hannah Cairo that explains the conjecture and her results [1]

Also, Terence Tao hinted at some further advances some time ago [2], does anyone know more about that?

[1]: https://www.youtube.com/watch?v=3ZeH_8sTyKA

[2]: https://mathstodon.xyz/@tao/114003793236630744

mellosouls 1 hours ago [-]
Yes, presumably this:

https://terrytao.wordpress.com/2025/02/25/the-three-dimensio...

bradly 29 minutes ago [-]
While extremely talented, I am not surprised to find this coming from a teen. Major mathematical discoveries often have come from those in their mid 20’s with the greater discoveries being skewed towards the younger 20s and teens. I think this because pure mathematics is just so creative.
paulpauper 2 hours ago [-]
Trying to do anything original and novel in math is extremely hard at any age. to do it at 17 is insanely talented. congrats
pillefitz 2 hours ago [-]
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pinoy420 2 hours ago [-]
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ledauphin 2 hours ago [-]
here's a dumb question:

she's starting her Ph.D. this fall - hasn't she already achieved it? What is the theory behind expecting someone who has solved a decades-old problem to do some "second" thing to prove that they have extended the bounds of human knowledge?

EvgeniyZh 55 minutes ago [-]
Ph.D. is training in how to do research. Solving one, even very hard problem not necessarily means that you don't need such training. It's especially tricky with counterexamples which sometimes question of raw talent and luck rather than skill.

The next step for someone who has PhD and want to stay in academia is postdoc. After solving one problem, you would not necessarily have what's needed to get a good postdoc, such as clear research agenda or proof of ability to publish consistently.

daxfohl 30 minutes ago [-]
A PhD is as much a stamp of endurance as it is a stamp of intelligence or accomplishment.
parpfish 2 hours ago [-]
But what does somebody do with a PhD at age 17? I can’t imagine hiring them as a prof when they’re so young. It’s not a bad idea to just take a couple years to continue your already productive collaboration while getting mentored on the non-math parts of being a mathematician.
ics 2 hours ago [-]
IIRC Erik Demaine (https://en.wikipedia.org/wiki/Erik_Demaine) started teaching at 20 and had his PhD. I can't remember if I first saw his name because of the MacArthur Grant or one of those science documentaries but one of his pages was on the frontpage here a week or two ago and it seems like he's been thriving.
nextos 2 hours ago [-]
A PhD in the US requires a lot of coursework, aside from research. Perhaps, she is interested in that. Otherwise, some universities, especially in EU, offer PhDs by publication. She could simply wrap up her counter-example publication (https://arxiv.org/pdf/2502.06137) as a thesis and possibly graduate. Sometimes, you can even do this without a supervisor.
xg15 2 hours ago [-]
Sounds as if she even has a potential supervisor:

> “It took me a while to convince Ruixiang Zhang [the professor of the course where the problem had been posed] that my proposal was actually correct,” Cairo says

> At the University of Maryland, she will continue working under the supervision of Zhang. “He helped me so much, and I’m really grateful. Beyond his class, which I loved, he spent countless hours tutoring me,” she recalls.

pclmulqdq 43 minutes ago [-]
PhD by publication usually takes a bit more work. I think they tend to want 3 related papers in a field.
almostgotcaught 24 minutes ago [-]
That's a rule of thumb for applied sciences. Plenty of theory PhDs graduate with 1 or 0 papers.
pclmulqdq 20 minutes ago [-]
Nobody gets a PhD by publication with 0 publications. This is usually a backdoor for people who have done a lot of work in a field, certainly far more than a PhD thesis, and have just never gotten the credential.
stogot 36 minutes ago [-]
What level or type of publication is required?
pclmulqdq 14 minutes ago [-]
They must be peer-reviewed journal papers and I believe they tend to prefer if at least one is well-cited or significant, especially if you have only three papers. It is generally harder to get a PhD by publication than to get a PhD the normal way.
eviks 54 minutes ago [-]
There is no deep theory here, bureaucracy doesn't think deep.
MPSFounder 13 minutes ago [-]
Great question. I have a PhD. People forgot the purpose of a PhD. Hannah effectively achieved what many with a PhD fail to do, and that is contribute novel research. A PhD in the US (only place I can comment on) has lately been focused first and foremost on a) preparing for academia, which entails teaching and a lot of courses, and b) research for industry positions (many students in my cohort were from China or India and this was their segway into a job in the US). I agree a PhD should be purely focused on research and extending human knowledge. In practice, it is a business where students go to conferences to promote their PI's work, where Universities get cheap lecturers in the form of TAs, and where many mediocre students write incremental papers to secure an RnD position (change this by a little and see how it affects your results. This is your paper). I am very impressed by Hannah's work though and she embodies the selfless nature of research that is very much missing. I see too often people seeking to advance their own career and pick a PhD route of least resistance. While they are entitled to maximize profits, and oftentimes do not want to go to academia where solving the impossible is admired, we must remember discoveries often hinge on challenging problems and a selfless pursuit of the impossible. This is just my opinion based on what I saw in my cohort and at 30+ conferences
2 hours ago [-]
Keyframe 2 hours ago [-]
Original title is more informative than the edited one here.
leephillips 2 hours ago [-]
I submitted under an approximation of the original title, and it was edited within seconds.
miles 1 hours ago [-]
There is too much "helpful" title modification of late. The original title itself fits within HN limits:

"A 17-year-old teen refutes a mathematical conjecture proposed 40 years ago"

The site's guidelines are clear[1] but increasingly ignored by some moderators:

"...please use the original title, unless it is misleading or linkbait; don't editorialize."

[1] https://news.ycombinator.com/newsguidelines.html

tomjen3 2 hours ago [-]
>One day, he proposed proving a special, much simpler case of the conjecture as a homework assignment. As an optional part, he included the original conjecture

There is a lesson there: always give people an opportunity to excel, if you can.

sshine 22 minutes ago [-]
I remember at first year of university being presented with a bunch of “simple” problems early on, such as the Collatz conjecture.

I remember wanting to spend time trying to explore what a solution might look like, because such simply formulated problems must have equally simple solutions.

Maturing and getting a better understanding of my intellectual capacity, I have opted to solve practical problems with a much bigger chance of success and absolutely no groundbreaking qualities.

But I liked being taken serious from the start, and I think it’s important to try and solve hard problems before you grow stuck in the real world.

rendall 3 hours ago [-]
https://archive.is/Nr1hH
scythe 4 hours ago [-]
Paper here:

https://arxiv.org/abs/2502.06137

I had the opportunity to take a harmonic analysis course in grad school. I passed it up. It was only tangentially related to my research at the time.

munchler 2 hours ago [-]
I had never heard of the X-Ray Transform until I happened to read about it in the New York Times today, and then here it is again.

https://www.nytimes.com/interactive/2025/06/30/science/math-...

dekhn 1 hours ago [-]
This sort of transform (what I think many people call inverse problems) is quite common in reconstruction problems- that is, where you pass light or other EM through an object, the light scatters, and hits a detector. Typically you want to find the minimum error reconstruction. See more here: https://en.wikipedia.org/wiki/Radon_transform
raincom 2 hours ago [-]
Great achievement. Now Princeton Math department will ask her to join their school for Ph.D.
kemitchell 3 hours ago [-]
Refuted?
zahlman 3 hours ago [-]
Yes, either proving a true conjecture or refuting a false one is "solving" it.
qsort 3 hours ago [-]
The Mizohata-Takeuchi conjecture is a statement in the form "For all <x> (a bunch of math)".

Showing that there exists an x such that the statement is false disproves the conjecture.

She found a counterexample.

mgiampapa 2 hours ago [-]
She found more than one way of disproving it in the process.
gilleain 3 hours ago [-]
Yes, found a counterexample to the conjecture.
xyst 37 minutes ago [-]
[flagged]
fourthark 29 minutes ago [-]
Harmonic analysis?
old_man_cato 3 hours ago [-]
[flagged]
dang 4 minutes ago [-]
Could you please stop posting unsubstantive comments to Hacker News? we're trying for something different here.