Hannah Cairo: 17-year-old teen refutes a math conjecture proposed 40 years ago

389 pointsposted 15 hours ago
by leephillips

99 Comments

bradly

11 hours 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.

TechnicalVault

9 hours ago

It doesn't help what we've designed a rather silly academic system where principal investigators are forced to spend a good deal of their time thinking where they'll be applying for their next grant. We also optimise the system for short term thinking rather than long games. There are some exceptions in research institutes but I think young people are the ones who have the clearest minds because of it.

Qem

3 hours ago

I wonder how many years on average people can dedicate themselves to think deep about research problems, before they must stop thinking and start managing, or quit the race.

thelock85

41 minutes ago

You could replace “research” with nearly any term not undergirded by a direct profit motive (eg civics, politics, education, community health, urban planning). Or maybe it’s just (and you may be saying this) that one can only dedicate themselves up until a clear profit opportunity appears.

jebarker

9 hours ago

Whenever I hear this claim about younger mathematicians I wonder if it still holds true (or really did historically). For example, Andrew Wiles proved Fermat’s Last Theorem in his 40s and there are numerous examples of productive older mathematicians. But also I think the claim skews towards big flashy problems rather than the work of building mathematical frameworks, finding structural insights and finding connections between disparate areas (which requires broad experience rather than just young intensity).

Qem

3 hours ago

> there are numerous examples of productive older mathematicians

Curious about the extreme cases. Did any centenarians ever managed to come with an outstanding original math result? If it didn't happen before, I hope to see it happening in the next decades, given current demographic trends.

sebmellen

an hour ago

Erdős? I’m sure the Ritalin helped.

loeber

6 hours ago

I think this hasn't been true in a long, long time. The most recent example of major contributions coming from someone in their 20s would be Evariste Galois around the time of the French Revolution.

Teens? No way, not really ever.

kevinventullo

6 hours ago

Peter Scholze received his Fields Medal at 30 for work he carried out through his 20’s. However he is not the youngest recipient: J.P. Serre received his Fields medal at 27.

getnormality

3 hours ago

Before we get too excited about the Fields Medal as an indicator for age of great mathematical achievements, let's remember that it's only awarded to people under 40 for work done earlier, potentially many years earlier.

codedokode

7 hours ago

Probably it is because the first solved problem seems like fun, but solving problems daily as a job quickly become boring?

paulpauper

13 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

12 hours ago

Anything original, for that matter.

ledauphin

13 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

11 hours 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.

andy99

9 hours ago

Modern PhDs are not designed for people that are smart like this. She's a math savant that obviously has a unique and demonstrably effective way of looking at things, why destroy that with "training how to do research".

I hope she's found a program that will support her while realizing she's smarter than whomever is setting the rules, rather than something stifling.

mkl

9 hours ago

This is not true at all. Maths PhDs are excellent for this kind of person, and foster and grow such abilities. No matter how smart you are, training on how to do research is going to improve your capabilities and success.

parpfish

12 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.

beezlebroxxxxxx

10 hours ago

> I can’t imagine hiring them as a prof when they’re so young

Many institutions would actually jump at the chance. That's way better than a 35 or 37 year old burnt out from just finishing their PhD and getting onto the tenure track suffer-fest. Think of how many years of productive research she has in her. It used to be way more common until academia became so professionalized and bureaucratic.

j7ake

10 hours ago

In math or theoretical fields it’s not unheard of to have young professors. Terence Tao was full professor at 24. Wolfram at 21

parpfish

8 hours ago

She could still do a few years of PhD training and still be a super young prof like those two.

At 17 she’s so young that a uni hiring her would need to think about child labor laws

ics

12 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.

daxfohl

8 hours ago

Noam Elkies too, the youngest ever tenured prof at Harvard. Another parallel he had a pretty famous contradiction proof, of Euler's conjecture. But he didn't find that until age 22, so seems like this girl has a good head start!

ekaryotic

7 hours ago

theodore kacsynski started teaching at 22. a damn bright spark before he was victimised by the mind control experiment.

tehjoker

10 hours ago

When she graduates she'll probably be between 20 to 23 years old.

jovial_cavalier

5 hours ago

What does someone do with a PhD at age 35? Go into industry? Continue as a postdoc? Open a juice bar? It doesn't matter what she's going to "do" with it. It's accreditation of a certain degree of academic achievement, which she has achieved. Arguing that she doesn't deserve it or needs to earn it the "normal" way is stupid.

nextos

13 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

12 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

11 hours ago

PhD by publication usually takes a bit more work. I think they tend to want 3 related papers in a field.

stogot

11 hours ago

What level or type of publication is required?

pclmulqdq

11 hours 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.

almostgotcaught

11 hours ago

That's a rule of thumb for applied sciences. Plenty of theory PhDs graduate with 1 or 0 papers.

pclmulqdq

11 hours 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.

pcrh

9 hours ago

A PhD thesis is itself a publication.

PhDs "by publication" refers to not having to submit work additional that already published to the examining committee.

almostgotcaught

10 hours ago

> Nobody gets a PhD by publication with 0 publications.

Do you have a PhD from a theory department? I do. You're wrong.

pclmulqdq

9 hours ago

Lots of people get PhDs with no publications.

Nobody gets a PhD by publication without publications. It's literally axiomatic.

almostgotcaught

8 hours ago

It's amazing how many people on hn are experts on things they do not have the qualifications to be expert on.

> It's literally axiomatic.

You've made up some axiomatic definition of "by publication" that does not bear any resemblance to the actual definition. Consider that it's possible to

1. Submit a preprint to arxiv and have it count

2. Submit a preprint to a journal and defend before it accepted (or rejected)

3. Not submit anything anywhere and have the PhD itself count (almost all PhDs get an ORCID)

CJefferson

3 hours ago

I agree, you seem to be claiming to be an expert on something.

"PhD by publication" is a specific thing, it's in italics in the previous post.

My Universities offer a "PhD by publication". You basically staple together a bunch of your publications, and write a brief intro. It saves you writing a full PhD document. But, the standard on those publications is quite high -- you certainly wouldn't get one from preprints to arxiv at any University I've ever worked at.

Of course, you can get a PhD with no publications, just write a good PhD. Lots of students do taht.

almostgotcaught

3 hours ago

Did you know that there are universities outside of Europe? And that in those universities, "3 publications plus intro and conclusion for a PhD" is also called (usually) PhD by publication (sometimes it is called a kitchen-sink PhD). And my point was that that rule of thumb does not apply to theory students.

Note the italics please.

So I'm sorry you're right I'm not in expert in Europe's monopoly on the phrase "PhD by publication" but who would want to be an expert in trivial bs like that (answer: apparently you and the other guy!)

pclmulqdq

8 hours ago

Are you aware that "PhD by publication" is a real thing that is a separate path than a normal PhD? It is relatively common for schools in some European countries to offer these, but not that common outside Europe.

This is a process where you can write your "dissertation" by putting an intro and a conclusion on ~3 papers you have already published and get a PhD that way. You enroll in the school for ~3 months, write the missing parts, and that's it. This is a flexible path to a PhD for industry researchers or other people who have a lot of expertise and have pushed the boundaries of a field but did not do a formal PhD program.

I have never heard of anyone doing this with ArXiV preprints or any school accepting this path if they are not referreed papers. I would love to see an actual counterexample if you have one.

pcrh

8 hours ago

>You enroll in the school for ~3 months, write the missing parts, and that's it.

There are degree mills that do what you describe.

There is also the format in countries such as Germany or the Netherlands where one typically "bundles" one's publications into a thesis. However, the work is typically done in the context of supervised doctoral programmes and no less rigorous than that done under different PhD studies formats.

skissane

8 hours ago

A PhD by publication sounds very similar to a higher doctorate (DSc, DLitt, etc). Substantive (as opposed to honoris causa) higher doctorates are awarded based on publication record only. To be eligible for a substantive higher doctorate, you generally are expected to have a PhD first - but it might not be an absolute requirement. You’d generally expect a bunch of papers, but in principle a single publication (if sufficiently groundbreaking) could be enough. While this is very impressive for a 17 year old (I wish I could have done that at 17, or at any other age for that matter), it probably isn’t significant enough for a higher doctorate all by itself. If she’d proved P=NP, different story. (Who knows, maybe she shall-well, probably not, but I’d be very happy to be proven wrong about that.)

daxfohl

11 hours ago

A PhD is as much a stamp of endurance as it is a stamp of intelligence or accomplishment.

eviks

11 hours ago

There is no deep theory here, bureaucracy doesn't think deep.

YeGoblynQueenne

10 hours ago

A PhD can be an opportunity to learn, or an opportunity to brag. I'm guessing the teen in the article is going to go for the first one.

MPSFounder

11 hours 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

vladms

9 hours ago

I do not think there is "one" purpose for a PhD, and not everyone gets the same thing from it - it depends on what are a person's strong and weak points. I have seen very smart people not able to explain at all their work and during a PhD they were forced to improve. I have seen very good presenters that were forced to do some actual work. I have seen people that were convinced they can solve anything (as in some parts of the world the bachelor and master focus to much on solvable problems) understand that sometimes there just isn't a clear, nice solution to a problem.

On average someone that does have a PhD will have a wider set of skills, like understanding of the complexities of the field, resistance to frustration, capability to do research and ability to communicate.

user

13 hours ago

[deleted]

tomjen3

13 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

11 hours 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.

gopher_space

8 hours ago

I give all of my hard problems to juniors.

cjensen

2 hours ago

The best thing about juniors is they don't know a problem is impossible, so they just do it.

scythe

14 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

12 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

12 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

schoen

9 hours ago

That's a funny coincidence that the "Radon" there is a person's name and not the radioactive element or its emanations.

echoangle

9 hours ago

Not really related but similar situation and I found it funny when I realized it:

The Poynting-Vector (https://en.wikipedia.org/wiki/Poynting_vector) indicates the direction of the energy flow of a magnetic field, but it’s named after a physicist called „Poynting“, not because it is „pointing“ somewhere. I thought the „y“ in poynting was a typo when I first read it.

lordnacho

10 hours ago

How often does someone produce work that is normally taught to people who are older than the person who discovered it?

Euler was 41 when he discovered his famous identity, the kind of thing people learn in school.

Even Newton was 21 when he invented calculus, the sort of stuff that you might find late teens learning.

Galois by a couple of years? He died at 20, and I suppose they teach that stuff sometime mid uni?

louistsi

9 hours ago

Galois Theory was a third year second semester course at my university when I studied there, which corresponds to 20-21yo in the UK system.

make3

2 hours ago

I would assume by having parents involved one way or another early on, with things like private, 1:1 education or the parents themselves being researchers

You also need the young person needs to also be extremely motivated and have what it takes. So both the contextual and individual means.

chengiz

10 hours ago

> The conjecture was widely believed to be true — if so, it would have automatically validated several other important results in the field — but the community greeted the new development with both enthusiasm and surprise: the author was a 17-year-old who hadn’t yet finished high school.

This article is quite poorly written. Case in point above. If the conjecture was believed to be true, refuting it would be news in itself, deserve more than half a sentence, and have nothing to do with the age of the refuter. It should have been simple to add a line about the "other important results" and not violate show not tell. AlsO I fail to see the relevance of mentioning the Spanish academy? The researcher is from Bahamas/USA, it's just the writer is from Spain?

MarcelOlsz

10 hours ago

>This article is quite poorly written.

Her last name is misspelt in the very first paragraph as well.

libraryofbabel

10 hours ago

Oh come on. This is in the Spanish newspaper El Pais. Context and audience matters. It’s simultaneously news about a math problem, an article about a young mathematician, and an article about things that happened at a math conference in Spain, which is where they presumably interviewed her.

uselesswords

8 hours ago

Sure context and audience matters, but even outside of that the article is rather poorly written. This part in particular should really emphasize that she disproved the conjecture, as it stands it almost sounds like she proved it:

> Cairo solved the so-called Mizohata-Takeuchi conjecture, a problem first proposed in the 1980s that had kept the harmonic analysis community had been working on for decades. The conjecture was widely believed to be true — if so, it would have automatically validated several other important results in the field — but the community greeted the new development with both enthusiasm and surprise: the author was a 17-year-old who hadn’t yet finished high school.

tzs

4 hours ago

From the first paragraph of the article:

> "After months of trying to prove the result, I managed to understand why it was so difficult. I realized that if I used that information correctly, I might be able to refute the claim. Finally, after several failed attempts, I found a way to construct a counterexample [a case that does not satisfy the studied property and therefore proves it is not universally true]."

That makes it quite clear that she refuted it.

billforsternz

7 hours ago

This excerpt features a terrible typo, so I agree it's poorly written, or at least not properly proof read. I don't agree with your specific criticism of the excerpt though. I think the excerpt makes it perfectly clear she disproved the conjecture by highlighting how that was potentially a disappointing outcome.

The writer introduced and resolved the potential disappointment much more elegantly and in far fewer words than I can manage here by paraphrasing. I admire that and feel it's indicative of good writing, albeit spoiled by an earlier typo.

tzs

4 hours ago

> It should have been simple to add a line about the "other important results" and not violate show not tell.

Only a very tiny fraction of the publication's readers will have any idea what the heck the Mizohata-Takeuchi conjecture is. Naming the important results that Mizohata–Takeuchi being true would have validated would have been just technobable to nearly everyone reading the article.

user

9 hours ago

[deleted]

user

10 hours ago

[deleted]

waym0re

5 hours ago

Anyone have a link to her supposed first paper on number theory? I have my doubt on her counter-example. It uses asymptotic methods rather loosely.

raincom

12 hours ago

Great achievement. Now Princeton Math department will ask her to join their school for Ph.D.

Keyframe

13 hours ago

Original title is more informative than the edited one here.

leephillips

12 hours ago

I submitted under an approximation of the original title, and it was edited within seconds.

miles

12 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

user

10 hours ago

[deleted]

layer8

10 hours ago

As the submitter, you can re-edit the title after submission (for some limited time period).

kemitchell

13 hours ago

Refuted?

zahlman

13 hours ago

Yes, either proving a true conjecture or refuting a false one is "solving" it.

qsort

13 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

12 hours ago

She found more than one way of disproving it in the process.

gilleain

13 hours ago

Yes, found a counterexample to the conjecture.

old_man_cato

14 hours ago

[flagged]

dang

10 hours ago

Could you please stop posting unsubstantive comments to Hacker News? we're trying for something different here.

andrewinardeer

10 hours ago

"Ciaro says it required several tools, including fractals, and she had to arrange everything very carefully."

Article could at least spell her name correctly.