[HN Gopher] Surprise computer science proof in combinatorics
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       Surprise computer science proof in combinatorics
        
       Author : theafh
       Score  : 209 points
       Date   : 2023-03-21 14:23 UTC (8 hours ago)
        
 (HTM) web link (www.quantamagazine.org)
 (TXT) w3m dump (www.quantamagazine.org)
        
       | czbond wrote:
       | I'm a practical person. What's the point of spending "time"
       | (brain cycles) on such problems? Is it just a mathematician's
       | version of brain teaser?
       | 
       | What useful development comes out of such?
        
         | kccqzy wrote:
         | Before cryptography, all of number theory was considered just
         | one brain teaser after another. Without those brain teasers we
         | wouldn't have secure private communications.
        
         | nostrebored wrote:
         | Well, you can now use this as a tool to show that if you can
         | reduce part of a problem to creating a progression free set you
         | can use that to show the complexity of a problem.
         | 
         | The ways I've seen combinatorics (and graph theory!) interact
         | with software engineering is typically showing that a problem
         | is too expensive to solve at scale.
        
         | LolWolf wrote:
         | Eh, someone just suggested that a bound of this form might
         | break some cryptographic assumptions for finite fields of
         | (large) prime order. (This is not obvious to me, but it's a
         | point that I think is worth considering, and already would show
         | that such a result is useful.)
         | 
         | It's very hard to know how these things end up being useful.
         | Even if a specific piece of knowledge isn't useful by itself,
         | it can lead to things that _are_ useful down the line. It 's
         | both very hard to know which ones will be, or which ones do
         | lead to actually useful results; for example, think of work on
         | propositional logic which ends up being the bedrock of
         | computation, work on elliptic curves (cryptography), work on
         | PDEs (physics), quantum physics (transistors), photonics
         | (communications), etc.
         | 
         | Some fields have pretty "fast-to-application" times, but it's
         | not always clear which ones will _not_ yield useful results.
         | Plus, and here's the real, honest answer: all of this shit is
         | very fun! Why _not_ do it?
         | 
         | I'm also a (somewhat) practical person, and that guides many of
         | the problems I try to solve, but sometimes there's just such a
         | tantalizing puzzle that it's hard not to resist! It's pretty
         | damn hard to "only" work on "useful" stuff and not be just an
         | ok academic/programmer/etc., you have to let yourself get nerd-
         | sniped into doing random things. With very high probability,
         | these little "side-quests" end up being very useful down the
         | line, for one reason or another.
        
         | semi-extrinsic wrote:
         | The flippant answer is https://abstrusegoose.com/504
        
           | mcguire wrote:
           | Any mention of Lobachevsky requires this:
           | 
           | https://youtu.be/gXlfXirQF3A
        
         | garbagecoder wrote:
         | Understanding mathematics before we understand what problems it
         | solves happens all the time. Maybe nothing will come of this,
         | but because we can't know that, it's worth researching.
         | 
         | People didn't believe there was non-Euclidean geometry and not
         | long after the taboo was broken, we had General Relativity.
         | Einstein was a genius, but he did not invent the math for GR.
         | Mathematicians like Riemann, Minkowski, Hilbert, Ricci, Levi-
         | Civita and others created the mathematics for it first.
         | 
         | Finding the area under a curve or the tangent line of an
         | arbitrary curve were considered two unconnected brain teasers
         | until Calculus was invented by Newton and Leibniz and applied
         | to gravity by Newton.
         | 
         | The "Math First" approach has done more than enough to prove
         | its continued viability and without it you wouldn't have been
         | able to type that here.
        
         | rrobukef wrote:
         | A Hash Table's double hashing [1] creates an arithmetic
         | progression. Improving bounds of this theorem could lead to
         | faster, smaller hash-tables. This is the first wild speculation
         | I could come up with.
         | 
         | [1] https://en.wikipedia.org/wiki/Double_hashing
        
         | dahart wrote:
         | Maybe the question is what useful developments _haven't_ come
         | from mathematical play originally, and can't trace their
         | lineage to abstract brain teasers?
        
         | TheRealPomax wrote:
         | The fallacy is thinking that this was the puzzle. This is just
         | one piece in a puzzle that's so big no one person can see the
         | whole thing, and that we're using as a blueprint for large
         | parts of modern civilization _while_ still figuring it out. We
         | don 't even know whether we've completed most of the puzzle, or
         | whether the puzzle is actually vastly larger than what we've
         | already put together.
         | 
         | If you can't see why this is useful, then great: that's
         | literally what it means to be a layman. But that also means
         | that you don't know enough about the subject field for the real
         | answer (the one that explains what other maths this affects) to
         | satisfy your question because you won't know why _those_ things
         | would matter.
         | 
         | So you're going to get the layman's answer: "because this shows
         | that any work already performed in the assumption of its truth
         | is now known to be valid", which is critically important
         | because a _lot_ of what maths is used for in real life is based
         | on assumptions about the properties of numbers. Now _others_
         | can stop wasting their time trying to determine whether this
         | aspect of number theory can be relied upon, and under which
         | circumstances, and trying to find all expressions of it in both
         | software _and_ hardware in order to determine whether those
         | might have problems on a case-by-case basis. And at the same
         | time, this result allows others still to move forward with work
         | that is known to rely (in part!) on this property either being
         | true or false, for which it was previously uncertain whether it
         | would even be worth the effort because it was unknown whether
         | the results would turn out to be useless because no one knew
         | whether the basis it relied on was flawed.
         | 
         | As for what useful development comes out of things like this:
         | 
         |  _points at the computer you 're using to comment on HN
         | threads, and every single application on it that you've ever
         | used_
         | 
         | That.
        
         | Vt71fcAqt7 wrote:
         | >In late 2021, Kelley and Meka were analyzing the chances that
         | a team of players in a certain cooperative game would be able
         | to win, a standard type of computer science problem. It
         | occurred to them that techniques from research on the size of
         | progression-free sets might be helpful. But they found it
         | easier to directly study those techniques than to apply them to
         | the cooperative game. "My best idea for how to make progress on
         | this problem [was] to actually improve the tool itself, not to
         | use it in a more clever way," Kelley said.
         | 
         | I wish they went into more detail about how this problem was
         | relevant to the other problem.
        
           | jmblpati wrote:
           | I don't know what specific problem Kelley and Meka were
           | working on, but the connection between arithmetic progression
           | free sets and computer science (especially communication
           | complexity) is somewhat well established. See for example
           | this paper[1] which gives new constructions of "corner-free
           | sets" (which are closely related to 3 arithmetic progression-
           | free sets) by thinking about a specific communication
           | protocol.
           | 
           | [1] https://drops.dagstuhl.de/opus/volltexte/2021/14276/pdf/L
           | IPI...
        
         | phtrivier wrote:
         | We're mortals, the only relevantquestion is "is it a better use
         | of brain cycles than X".
         | 
         | Considering that way vaster amounts of brain cycles are devoted
         | to making people watch one more TikTok video, then, I think
         | this kind of brain-scratching is more useful than much of what
         | most of us do.
        
         | retrac wrote:
         | Mathematics continually surprises us when seemingly disparate
         | areas suddenly become linked, sharing some sort of relationship
         | that was not appreciated until much later.
         | 
         | Some think mathematics is something like a physical law, or
         | property of the universe. So figuring out such things may be
         | like fundamental physics research. Hard to quantify the value,
         | but there is value. Seemingly unrelated developments in
         | mathematics have had a habit of helping to solve problems in
         | physics in the past, at least. I don't think anyone really
         | expected the exciting new mathematics of statistics in the 18th
         | century, to one day be relevant to physics. But it would be.
        
           | chasd00 wrote:
           | > Some think mathematics is something like a physical law, or
           | property of the universe
           | 
           | my kid asked me if math was invented or discovered. i said
           | "invented", i hope i'm right considering he views me as some
           | all knowing oracle of information. just a little bit of
           | pressure there.
        
             | psychoslave wrote:
             | You missed a great opportunity to answer a simple "yes". ;)
        
             | truckerbill wrote:
             | Given the fact the rules exist whether we know about it or
             | not, I'm team discovered
        
             | layer8 wrote:
             | Computers were invented, but you could also say that we
             | discovered how universal computation works. It's not like
             | there's some fundamentally different form of computation
             | that we could have invented instead. Even more so in math,
             | the _truths_ in math are discovered, not invented.
        
               | claytongulick wrote:
               | The mathematical realm is a purely human construct.
               | 
               | There's no such thing as "one" in nature: there's not
               | "one" apple. An apple is a monstrously complex collection
               | of cells and dynamic chemical processes, it's not "one".
               | 
               | The concept of numbers are a tool that humans use to
               | categorize, summarize and model the world around us.
               | 
               | The "truths" we discover in math are only true in the
               | mathematical realm, which is an inexact model of the
               | physical realm. Useful, but undeniably a human construct.
               | 
               | So yes, math is invented.
               | 
               | Though we constantly discover new ways to use it in the
               | physical world.
        
               | mik1998 wrote:
               | > which is an inexact model of the physical realm
               | 
               | Mathematics have nothing to do with the real world.
               | 
               | The set of all true statements provable with a set of
               | axioms is determined only by the axioms. All the true
               | statements are already true whether we know they are or
               | not; in that sense math is like exploring the unknown
               | land that exists outside of the physical realm. It's
               | discovered.
        
               | layer8 wrote:
               | Just as one (no pun intended) example, the fact that
               | there are exactly five platonic solids in three-
               | dimensional space is not something that is invented. It
               | is discovered. And facts like that govern what is
               | possible in the physical world, for example what kind of
               | crystalline atomic structures can form. There is nothing
               | "invented" about that.
               | 
               | The fact that the physical space we live in has three
               | dimensions also isn't invented. These numbers, three and
               | five here, are not a human invention. They correspond to
               | facts we discovered, and they represent truths that are
               | independent of human existence or inventions.
               | 
               | Maths is exactly about that, discovering the fundamental
               | truths that, based on logic, we find couldn't have been
               | any other way.
        
               | claytongulick wrote:
               | It's a bit of a difficult concept to wrap our head around
               | because we've been taught to associate "number symbols"
               | and names with "things" since we were toddlers, but they
               | absolutely aren't the same thing.
               | 
               | There's no such thing as "three", other than a
               | categorization that we, as humans, apply to model the
               | physical phenomenon.
               | 
               | We've developed language and symbols over time to more
               | precisely model the things we observe, but it's important
               | to remember that our symbols are different from the
               | things they are invented to represent.
               | 
               | It's really hard to separate this abstract concept from
               | our observed reality when they are so tightly coupled -
               | the idea of "three dimensional space" is a model we've
               | constructed to categorize and represent, in a convenient
               | way, observed phenomenon that is too difficult to talk
               | about in other terms.
               | 
               | We didn't "discover" that there are three dimensions, for
               | example. We developed language and a mental framework for
               | categorizing space in such a way that we could more
               | easily reason about it and communicate our reasoning
               | effectively with others.
               | 
               | We didn't "discover" Ohm's law. We created a set of
               | units, names and concepts that would allow us to model
               | the relationship in an analytic way, between other
               | concepts such as current, voltage and resistance. Ohm's
               | law isn't not a fundamental law of nature. Above all
               | else, it's a series of struggles with language to
               | describe things we observe. "Ohm" as a unit of
               | resistance, "Voltage", "Amperage" - all of this was
               | invented in order to be able to reason about things we
               | were seeing, and it seems to be a good mental model and
               | tool for getting things done, but it is very different
               | than the actual reality.
               | 
               | We didn't "discover" the number three - we created the
               | concept of numbers and refined their meaning over time.
               | For a very long time, in most civilizations there wasn't
               | a concept of "zero" in number symbols. We needed a way to
               | communicate that concept though, so invented a symbol to
               | represent it.
               | 
               | Number systems and the symbols that represent them have
               | varied wildly throughout human history, and there appears
               | to be a neurological attachment in the human brain that
               | associates quantity with physicality (specifically
               | fingers) [1] that makes grokking this concept especially
               | difficult. When we become sophisticated enough that using
               | our fingers wasn't sufficient to reason and communicate,
               | we started using bone tally marks as a quantity
               | representation - but all of these things, fingers, tally
               | marks, glyphs - are just symbols that humans have created
               | over time to imperfectly model physical phenomena.
               | 
               | It's no different than any other sort of naming. We look
               | at differences between birds, and attach a symbol of
               | "hawk" to one, and "eagle" to another. There's no such
               | thing as "hawk" or "eagle" in nature, these are human
               | invented symbols that help us categorize and communicate
               | in a short-hand way, differences between species we
               | observe. Numbers are the same, but we've also invented a
               | bunch of rules for manipulating those symbols to
               | communicate more advanced concepts: addition,
               | subtraction, etc...
               | 
               | Now it's true, of course, that we discover new things all
               | the time. Frequently we need to invent new ways of
               | describing it. We discovered, by observing the stars,
               | that planets follow an elliptical orbit. We couldn't
               | describe that well using the tools we had, so invented
               | Calculus.
               | 
               | [1] https://en.wikipedia.org/wiki/History_of_ancient_nume
               | ral_sys...
        
               | layer8 wrote:
               | Math fundamentally isn't about the "names", it's about
               | the "things". We are doing it because we want to know
               | about the "things". The "names" are only incidental.
               | Saying that math is invented and not discovered gives the
               | impression that it is building fantasy castles in the
               | sky, whereas it really is about gaining knowledge about
               | absolute and objective truths, truths that exist
               | independent from any human inventiveness or creativity,
               | or from the choice of "names". The "names" are merely a
               | vehicle, a tool for that purpose.
               | 
               | To take an example from computer science, we discovered
               | that comparison sorting algorithms have a time complexity
               | of O(n log n). This discovery is independent from the
               | notation we use to express it, and independent from the
               | programming languages we use and independent of the
               | choice of sorting algorithm. It is a fundamental fact of
               | the matter, and there is nothing invented about it. Any
               | alien intelligence would end up with exactly the same
               | insight about sorting.
               | 
               | Or to give a more hands-on example: If you have two,
               | three, or four balls of the same size, you can arrange
               | them such that each ball touches all of the other balls
               | (a tetrahedron shape in the case of four balls). But you
               | can't do that with five or more balls. Convincing
               | yourself that that's true is an essential example of
               | doing math. And it is true regardless of what "names" you
               | use. You can also use apples and oranges if they are
               | approximately spherical and of the same size (or,
               | alternatively, "look the same from all angles").
               | 
               | For these reasons, when chasd00 tells their kid that math
               | is invented, not discovered, they are misrepresenting
               | what math is really about. The above example with balls
               | could be one way to illustrate to a kid how math isn't
               | invented. (I'm sure there are much better examples, this
               | is just from the top of my head.)
        
               | mypalmike wrote:
               | > The fact that the physical space we live in has three
               | dimensions also isn't invented
               | 
               | The concept of "three orthogonal dimensions" is a pretty
               | good model of the physical reality that is space.
        
               | sosein wrote:
               | While counting apples might be a useful example for
               | teaching children, they're hardly the only thing there is
               | to count. The putative abstraction isn't even in the
               | number "one", the abstraction you're complaining about is
               | in the chosen category of "apple". In other words, the
               | fact that something can be comprised of many things does
               | not change how many of that thing there are, nor does it
               | reveal some deep unnaturalness of numbers. It at best
               | casts doubt on our delimitation of objects.
        
             | nomemory wrote:
             | That is a good question for a kid.
             | 
             | Ask him back, if it's discovered, where was it "stored" all
             | this time.
             | 
             | If it's invented, does it mean that other potential
             | sentient species will have a different math than ours ?
        
             | anonymousDan wrote:
             | That's a really insightful question for a kid to ask! Not
             | sure I agree with your answer though, for me that's the
             | kind if thing it would be hard to prove either way
             | (ironically).
        
           | JohnMakin wrote:
           | not to nitpick, but there's a ton of stuff in mathematics
           | that is just defined out of convenience or convention, it's
           | not natural law. Rather, a better definition would be that
           | mathematics is a description of reality, rather than law
           | itself.
        
             | msm_ wrote:
             | Isn't it the same? Laws of physics describe how the
             | physical world works, similarly to "laws of math" that
             | describe how the mathematical world works. In both cases we
             | tend to define our laws in a way that's easy for humans to
             | use and understand.
        
         | jjtheblunt wrote:
         | The gist of the insight of exercise is that one is conditioned,
         | even if the exercise itself seemed pointless, for the
         | unpredictable in later situations.
        
         | chriswarbo wrote:
         | > What's the point of spending "time" (brain cycles) on such
         | problems?
         | 
         | What's the point of anything?
         | 
         | > Is it just a mathematician's version of brain teaser?
         | 
         |  _All_ of mathematics can be characterised as  "brain teasers".
         | Make of that what you will.
         | 
         | > What useful development comes out of such?
         | 
         | I'm not qualified for this particular example. However, it
         | seems quite number-theoretic, and number-theory has given us
         | such "practical" things as asymmetric encryption and universal
         | computation (Turing's famous paper from 1936 was titled "On
         | Computable Numbers", after all).
        
           | johnfn wrote:
           | > What's the point of anything?
           | 
           | Not that I disagree with you, but some things have an impact
           | on people's quality of life: nutrition, healthcare, and
           | psychological well-being.
        
             | YetAnotherNick wrote:
             | Psychological well being is definitely improved if people
             | could work on something they like and get praised/rewarded
             | for it. And I believe that is way people could get
             | interested in something. Best engineers I know of, had got
             | into their field because they are driven by solving problem
             | just for the sake of it.
        
             | jaqalopes wrote:
             | It's a big world, not everyone needs to be a
             | farmer/doctor/psychologist so some people who have other
             | skills do other things. Sometimes those other things help.
             | A lot of time they don't. For better or worse we live in a
             | society.
        
             | mcguire wrote:
             | So? What is the point of living?
             | 
             | :-)
        
             | n4r9 wrote:
             | I'd say there's a strong case that this has a positive
             | impact on the psychological well-being of anyone who's
             | interested in number theory.
             | 
             | Perhaps not that many people in the world understand the
             | formulation of the problem, but then not many people "get"
             | abstract art, either.
        
             | an_d_rew wrote:
             | > ... but some things have an impact on people's quality of
             | life: nutrition, healthcare, and psychological well-being.
             | 
             | I would perhaps classify that as "immediate" impact, not
             | "lack of impact".
             | 
             | Number theory has driven computer science, calculus,
             | statistics, and so on.
             | 
             | CS, calculus, stats... they all drive (for example)
             | "nutrition". For example, how do you know what a "vitamin"
             | is? How do you measure it? How do you quantify it's effects
             | on the body (and mind)? A whackload of analysis DEPENDS on
             | number theory for us to understand almost everything about
             | the natural world!
        
           | eddsh1994 wrote:
           | Farming provides food. Predicting the probability of water
           | spontaneously combusting, while interesting, provides much
           | less food.
        
             | TheRealPomax wrote:
             | You know what does though? Irrigation. You know what allows
             | you to optimally irrigate so you don't waste money that you
             | could be spending either on growing more crops or your
             | family? Maths.
             | 
             | Only a fool pretends the ground floor of a house is
             | worthless because they live on the second floor.
        
               | eddsh1994 wrote:
               | I'm not saying Math is useless, I'm saying there must be
               | tiers for topics in how useful they are such that someone
               | can say "Hey, that's pointless!" and one can't follow
               | with "Therefore all things are pointless". Or, that allow
               | me to rank niche topics in their usefulness.
               | 
               | Irrigation is very important. Now, is Irrigation Maths
               | more important to us as a species than Terrence Taos work
               | on spontaneously combusting water? Probably! Would it be
               | more useful to have PhDs be funded in optimizing food
               | routes between countries after climate change over game
               | theory applications for blackjack? Probably!
        
               | TheRealPomax wrote:
               | Unfortunately, no. Maths is so vast that what might seem
               | a trivial and silly brain teaser can turn out to unlock a
               | _massive_ problem in a seemingly completely unrelated
               | subfield of mathematics, and we won 't know until someone
               | discovers that link.
               | 
               | What someone might call "a silly little brain teaser"
               | today could actually result in a breakthrough paper weeks
               | (or centuries) from now in a different subfield because
               | someone far smarter than us realized that part of the
               | problem they were working was actually analogous to a
               | number theory related problem that was simplified, even a
               | tiny bit, by this solution. (Hell, Nash built his entire
               | career on spotting those kind of links and then telling
               | other mathematicians to focus on working out the
               | individual pieces)
               | 
               | Maths plays out over "we don't even know how long or
               | short" time scales. What's the use? We don't know, it's
               | probably completely useless. Until someone suddenly
               | realizes that it's not.
        
               | msm_ wrote:
               | >Now, is Irrigation Maths more important to us as a
               | species than Terrence Taos work on spontaneously
               | combusting water? Probably! Would it be more useful to
               | have PhDs be funded in optimizing food routes between
               | countries after climate change over game theory
               | applications for blackjack? Probably!
               | 
               | I imagine you would be equally annoyed at Euler in 1736
               | when he was wasting his time with bridge brain teasers
               | (and invented graph theory in the process) instead of
               | solving bubonic plague or optimizing irrigation. Science
               | just doesn't (in general) work the way you propose.
        
               | eddsh1994 wrote:
               | And the majority of science sit in empty libraries with
               | maybe a single citation by a postdoc trying to write
               | enough papers to get the next postdoc...
        
               | Invictus0 wrote:
               | OP didn't say all math was useless, just this math, which
               | yes is most likely completely useless.
        
               | gspencley wrote:
               | The interesting thing about the question is that there
               | really aren't any right or wrong answers.
               | 
               | People pointing out that maths is full of advancements
               | that had no immediately identifiable use at the time, but
               | that came to be useful later, is correct. Yet it doesn't
               | even begin to answer the OP's question.
               | 
               | I doubt very much that many people choose to pour their
               | lives into endeavours that they don't particularly enjoy
               | just because some hypothetical person at some
               | hypothetical future point in time might hypothetically
               | find a hypothetical use (hypothetically ;P).
               | 
               | The answer is that "value" presupposes the question
               | "valuable to who and why?"
               | 
               | Newton invented Calculus because he had an immediate use
               | for it. Other mathematicians pour themselves into solving
               | problems because they enjoy it and find a lot of reward
               | in the prospect of solving a previous unsolved problem.
               | Both are "valuable", just to different people for
               | different reasons.
        
               | Invictus0 wrote:
               | Yeah it's fine for mathematicians to amuse themselves,
               | the problem is when they demand salaries to do that and
               | taxpayers like OP rightfully ask "whats in it for me?"
               | And when the answer is "IDK but maybe in a century we
               | might have a problem this math is useful in solving" then
               | it's not surprising that no one wants to fund pure math
               | research. It's not the 20th century anymore when math
               | research was going to meaningfully improve someone's life
               | through the invention of things like electrical devices.
        
               | burnished wrote:
               | Thats a pretty myopic view of history there champ.
               | 
               | The pragmatic, practical perspective here is that funding
               | the egg heads has had incredible outcomes (and its so
               | cheap too), so dont let the simpletons shake the golden
               | goose down just because they don't understand anything
               | they cant fuck, fight, or eat.
        
               | Ar-Curunir wrote:
               | In which world do you think mathematicians are raking in
               | taxpayer money? Mathematics requires very little funding:
               | a blackboard, some chalk, a pen and paper, a desk, some
               | coffee. That's it.
        
               | gspencley wrote:
               | Yeah, if you force other people to pay for something then
               | you had better offer them an attractive value
               | proposition. Though public funding of mathematics and
               | other sciences is not what I thought we were discussing
               | :)
        
               | czbond wrote:
               | You described my thinking very well, and much better than
               | I. Thank you
        
               | TheRealPomax wrote:
               | Until it's not, because someone suddenly realizes that a
               | seemingly completely unrelated problem in a completely
               | different subfield that's holding up a major proof is
               | actually analogous to a problem where this result removes
               | a bunch of roadblocks.
               | 
               | That's the problem with math from a "so what is this good
               | for?" perspective: we don't know yet, but we sure have a
               | litany of instances where seemingly useless proofs had a
               | profound impact anywhere from weeks to centuries later.
        
               | JohnMakin wrote:
               | They were trying to solve a real world problem using this
               | kind of math, and then decided it'd be easier to improve
               | upon the math itself than to continue to pound at the
               | problem - so by definition, I'd say you're absolutely
               | wrong here, or they never would have started this proof
               | in the first place.
        
             | mcguire wrote:
             | What is the point of providing food? Surviving? Existing?
             | Is that the highest achievement? Is remaining breathing for
             | a few more seconds the greatest goal?
        
             | pixl97 wrote:
             | >Predicting the probability of water spontaneously
             | combusting, while interesting, provides much less food.
             | 
             | Unless you can make a prediction that water will combust in
             | low energy conditions, in which you can use this combusting
             | water to generate excess power. Then use that power to
             | compress nitrogen into ammonia, and then use that product
             | as fertilizer.
             | 
             | The British show Connections went over how completely
             | different things sometimes 'connect' and bring fruitful new
             | ideas.
             | 
             | The problem space of reality has emergent behaviors that
             | are not (easily?) predictable. Sometimes you have to
             | iterate large portions of it.
        
         | renewiltord wrote:
         | One can see it as peeking behind the veil to view the
         | underlying structure of the universe we live in. It permits
         | certain things and does not permit others.
        
         | Ar-Curunir wrote:
         | Most of the other comments focus on how and why theory research
         | often leads to "practically useful" outcomes down the line, so
         | I'll instead say that not all research has to be practical.
         | Sometimes people do things just because they're interesting and
         | fun.
         | 
         | Why do people play board games, or video games, or sports? Why
         | do people read fiction? Why do people have hobbies which
         | strictly distract from productive work time? The answer to any
         | of these questions is the same as the answer for "Why do people
         | do theoretical research?": it's fun.
        
         | sebzim4500 wrote:
         | It's normally extremely hard to guess the applications of this
         | kind of research. Having said that, almost all modern
         | cryptography relies on maths that was not obviously applicable
         | at the time.
        
         | ChuckMcM wrote:
         | Understanding the fundamental nature of numbers and sets will
         | allow a person to avoid working on solutions to their "real
         | world" problems which would be precluded by that nature.
         | 
         | Take cryptography for instance. Why large prime numbers? Why
         | elliptic curves? If you have proven the fundamental mathematics
         | behind factoring large primes, then you have a basis for
         | thinking that a cryptographic system based on large primes will
         | be reasonably secure.
         | 
         | Many of the developments you use everyday are based on the
         | understanding of just such "brain teasers" :-).
        
         | [deleted]
        
         | ramesh31 wrote:
         | >What useful development comes out of such?
         | 
         | Mathematicians aren't concerned with that at all. If something
         | they do ends up being useful to science and engineering, then
         | wonderful. But it's not the point.
        
         | davnicwil wrote:
         | I've spent a lot of time and brain cycles over the last decade
         | writing software, entire products actually, that now sit as
         | motionless bits on a disk somewhere, unused and useless.
         | 
         | In the process of creating them I had a lot of fun, honed my
         | existing skills and picked up new ones, broke out of various
         | boxes I had been stuffed into in terms of how to architect
         | systems, and just generally worked out my creative muscles.
         | 
         | I've also written a lot of software that is useful and used,
         | and in a practical sense makes (lots of) money.
         | 
         | It's meaningless to break out the time and cycles spent on one
         | Vs the other. The necessary skills required were enabled by one
         | another. Moreover it would have been to a large extent
         | impossible to determine _a priori_ which would be which.
         | 
         | Am I an impractical person because I've spent time and cycles
         | on the former?
        
           | pixl97 wrote:
           | Yep, 'fun training' is one of those things you never know if
           | it could pay off, but because you know the information now
           | there is a much higher chance it is going to pay off for you.
        
         | alecst wrote:
         | I have a friend working on lidar for a military contractor. He
         | uses these exact theorems to design beam pulses for measuring
         | distances of asteroids and stuff. The idea is to construct
         | beams so that you can tell by the autocorrelation function the
         | exact distance away an object is. It turns out that these weird
         | kinds of integer sequences can help you design beams that give
         | the autocorrelation function this property.
        
           | czbond wrote:
           | This sounds really interesting, thanks for sharing.
        
         | pnut wrote:
         | Lazy loading solutions doesn't work when there's no library of
         | solutions to pull from.
         | 
         | Humanity already tried thinking it was better than the selfless
         | pursuit of knowledge, that path leads nowhere good.
        
         | aaomidi wrote:
         | This has significant implications for randomness and entropy.
         | 
         | I can already see it being useful for verifying entropy and for
         | verifying anonymization of statistical data.
        
         | ubj wrote:
         | Neural networks were first prototyped in the 1950's [1]. How
         | practical was it to study them back then?
         | 
         | Aleksandr Lyapunov's theory of stability for dynamical systems,
         | which forms the bedrock for much of control theory, was first
         | proposed in 1892 and went unnoticed until the 1930's [2]. How
         | practical was it for Lyapunov to study that topic?
         | 
         | It's virtually impossible to predict which mathematical tools
         | will be "practical" or "useful" in the future. The point is
         | that if someone needs the tool down the road, they'll have
         | access to the solution due to the efforts of these
         | mathematicians.
         | 
         | [1]: https://en.wikipedia.org/wiki/Neural_network#History
         | 
         | [2]: https://en.wikipedia.org/wiki/Lyapunov_stability#History
        
           | ilamont wrote:
           | Many other fields too.
           | 
           | Mendel's discoveries weren't appreciated until after he died.
           | When Narinder Singh Kapany invented fiber optic cable in the
           | 50s he had no idea it would lead to revolutions in computer
           | networking, gastroenterology, and other fields.
        
           | riku_iki wrote:
           | there is a huge chance this advancements could be invented
           | maybe in more efficient form when need and time come.
        
             | deredede wrote:
             | Proofs (both results and techniques) are a mathematician's
             | ammo. It is not good strategy to wait for a war to start
             | before building ammo.
        
               | riku_iki wrote:
               | And then you open ammo storage when you need it and see
               | it is polluted by 99.9% of irrelevant garbage.
               | 
               | Math is like code: technical debt makes moving forward
               | much harder.
        
           | phendrenad2 wrote:
           | > It's virtually impossible to predict which mathematical
           | tools will be "practical" or "useful" in the future
           | 
           | On a long enough timeline, you're right! But if we limit
           | ourselves to, say, the next 5,000 years, it gets a lot easier
           | to accomplish. ;)
        
             | asynchrony wrote:
             | How does limiting the timeline to 5,000 years enhance our
             | ability to predict the future?
        
               | phendrenad2 wrote:
               | The more you limit your timeline, the easier is is to
               | predict the future. That's why we only have 10-day
               | weather forecasts.
        
             | ubj wrote:
             | Good point, maybe a better way of phrasing it would have
             | been "It's virtually impossible to predict which tools will
             | _not_ be useful" :)
             | 
             | Fast Fourier transforms, complex numbers, complexity
             | classes, etc. are clearly useful. It's much harder to
             | rigorously claim that a result will _never_ be practical or
             | useful.
             | 
             | Just to be clear, I think it's fair to say that a result
             | isn't _immediately_ useful. But who can say whether or not
             | it will have a more practical application down the road?
             | Only time will tell.
        
           | pciexpgpu wrote:
           | And the entire works of Church and Turing...
        
             | xen2xen1 wrote:
             | Or the guy who just wanted to extend the works of
             | Aristotle, and created binary...
        
               | llamaz wrote:
               | Leibniz did that from memory, although the stoics deserve
               | the credit for propositional logic (which can be reduced
               | to a collection of truth tables). and contrary to popular
               | belief Boole actually extended Aristotle's syllogisms
               | (reduced the conventional syllogisms to computation using
               | matrices of 1s and 0s) rather than create a today's
               | binary logic.
        
         | the88doctor wrote:
         | Some number theory results about sequences and progressions can
         | be applied to create more efficient algorithms to approximate
         | the solutions to multi-dimensional integrals that come up in
         | physics (especially solid state physics on lattices).
         | 
         | Solid state physics problems of that sort are used in the
         | process of engineering new materials (e.g. a more efficient
         | dielectric for capacitors, a magnetic material that can store
         | magnetic memory data at higher temperatures without
         | destablizing, a higher temperature superconductor, etc). Idk if
         | this particular result has such an application, but I wouldn't
         | be surprised if it did.
         | 
         | In addition to solid state physics, "special functions" show up
         | in many areas of applied math and physics, including the
         | design, calibration, and data analysis of/from MRI machines and
         | antennas. Many special functions including the hypergeometric
         | functions can be approximated more efficiently using fancy
         | number theory algorithms.
         | 
         | There is also a broad category of physics and chemistry
         | problems that are best solved by Monte Carlo simulations, and
         | sometimes Monte Carlo approximations can be made using many
         | fewer iterations by choosing a set of points within the sample
         | space that satisfy number theoretic constraints.
         | 
         | Also, physics models often inspire machine learning models so
         | it's not impossible that some niche ML algorithm could
         | eventually benefit from a faster algorithm that uses this
         | result or a derivative of it.
         | 
         | None of these directly answer your question about a definitive
         | application for this particular number theory result, but I
         | hope it gives you an idea of what it could potentially be used
         | for. The closest analogy I know if is that certain multi-
         | dimensional Monte Carlo integral approximations can be done
         | orders of magnitude more quickly if you choose lattice points
         | whose coordinates satisfy some similar-ish constraints to the
         | ones described for this problem.
        
         | screye wrote:
         | All fundamental research is odd like that. Someone has to make
         | significant progress on a 'useless' topic before some semblance
         | of usefulness starts becoming visible.
        
         | burnished wrote:
         | There is no direct practical reason. Other people are giving
         | you the long term outlook view, why it is valuable in
         | aggregate, but if you were aiming for immediately practical
         | results neither math nor CS would fit the bill.
         | 
         | I can't speak for others but for me math is kind of like a
         | brain teaser on crack. It is immensely satisfying to think
         | about and I would imagine most mathematicians get a similar
         | kick out of it. Not a mathematician myself mind you.
        
         | ano88888 wrote:
         | lets just hope that politicions who controls the flow of
         | resource are not as shortsighted as you or we are doomed. The
         | computer and all the software won't be exist without this
         | boring and pointless mathemathics from a long time before
        
         | haha69 wrote:
         | Very similar answer to this - https://www.themarysue.com/tyson-
         | space-exploration/
        
         | alfalfasprout wrote:
         | The point is to advance knowledge of mathematics. Knowledge is
         | a practical pursuit in and of itself.
        
         | bena wrote:
         | Sometimes, discovering these proofs makes the math easier. If
         | we know X is the case for all Ys, and X is easier to compute,
         | you can use X where you would use Y before. Of if you know X is
         | true for all Ys, you can skip the part where you have to verify
         | that your Y has X property. Because we now know it must have
         | it.
         | 
         | And it's math all the way down in computers. So anything that
         | makes math easier or quicker has the potential to affect
         | anything a computer can process.
        
         | fooker wrote:
         | A practical person doesn't usually discover or invent something
         | which turns out to be practical in the long run.
        
         | heikkilevanto wrote:
         | For a long time certain mathematicians took great pride in
         | studying the most useless part of their field, prime numbers.
         | Without their studies we would not have modern cryptographic
         | techniques (RSA, SSL, HTTPS). And no bitcoin either.
        
       | giantg2 wrote:
       | Ok, but what's the use of this data set? Like how does this
       | improve something in the world?
       | 
       | Edit: why disagree... with me asking questions?
        
         | dang wrote:
         | " _Please don 't post shallow dismissals, especially of other
         | people's work. A good critical comment teaches us something._"
         | 
         | https://news.ycombinator.com/newsguidelines.html
        
           | giantg2 wrote:
           | I'm not posting a shallow dismissal. I'm legitimately asking
           | what this applies to since I didn't see anything in the
           | article about potential application. It's fine if there
           | aren't any potential applications too, just like the
           | videos/articles about Rubik's Cubes solving - the
           | people/solutions are impressive even if it doesn't have any
           | practical applications.
        
         | BeetleB wrote:
         | > Ok, but what's the use of this data set?
         | 
         | Same use as the rest of mathematics: Entertainment for those
         | interested in the topic.
        
         | burnished wrote:
         | You must be confused, the title specifies computer science and
         | mathematicians - the default assumption here should be that if
         | it is useful no one is going to realize for some decades.
        
       | mabbo wrote:
       | I feel like Quanta just has Terry Tao on speed dial at this
       | point, and that he loves to answer the call. They always ask him
       | about this stuff for their math articles and he always gives
       | great answers.
       | 
       | > That Kelley and Meka managed to spot the strength of once-
       | overlooked ideas shows the often fitful nature of mathematical
       | progress -- a quality that to Tao is more of a blessing than a
       | curse. "It's not always the case that math just gets harder and
       | harder and harder," he said. "Thank God."
        
         | uptownfunk wrote:
         | Hey nothing wrong with that! Huge fan of Terry Tao. Something
         | magical about how their brains work.
        
           | mabbo wrote:
           | It definitely wasn't a complaint, haha.
        
       | paulpauper wrote:
       | This is why America's obsession with trying to boost math scores
       | is possibly a waste of time and money. No amount of math literacy
       | will ever approach anything like this. Those who are gifted and
       | motivated enough will learn the material anyway and there are
       | enough professors who can teach it.
       | 
       | People who are professionals are so way far above and beyond
       | anything done by non-professionals. It's not like that with
       | reading or writing, in which knowing how to read means you can in
       | theory appreciate almost any book.
       | 
       | I think more emphasis should be on learning the basics, which
       | enough kids find hard enough to do. No reason to try to make high
       | schoolers learn algebra 1 & 2.
        
         | tmhn2 wrote:
         | The authors of the paper are academics in university CS
         | departments with heavy math backgrounds (one with a B.S. in
         | mathematics, another was a visiting professor at MIT dept of
         | mathematics). I don't understand what you mean or how it
         | relates to the article or surrounding circumstances.
        
         | permo-w wrote:
         | >there's no point planting seeds because plants will grow
         | anyway
         | 
         | did you have a bad maths teacher at some point?
        
       | mherdeg wrote:
       | I had a bit of trouble grappling with this.
       | 
       | What is the largest AP-3-free set for, say, the integers from 1
       | to 100? What is the largest N where we've computed it explicitly
       | / how expensive is that to do?
        
         | LegionMammal978 wrote:
         | According to the OEIS [0], the set has size 27; you can find
         | its terms in the Dybizbanski reference [1]. Presumably, it's
         | been computed up to N = 211, where the B-file ends.
         | 
         | [0] https://oeis.org/A003002
         | 
         | [1] https://doi.org/10.37236/2061
        
       | unsupp0rted wrote:
       | > Though both Bloom and Sisask had other pressing matters to
       | attend to at the time they received the email -- Bloom had just
       | adopted a puppy, while Sisask was in the middle of moving -- they
       | quickly set to work verifying the new paper.
        
       | thirdmunky wrote:
       | Source paper: https://arxiv.org/abs/2302.05537
        
         | n4r9 wrote:
         | Plus much shorter write-up from Bloom and Sisask:
         | https://arxiv.org/abs/2302.07211
        
           | [deleted]
        
           | red_trumpet wrote:
           | I think you mean this one: https://arxiv.org/abs/2302.07211
        
             | n4r9 wrote:
             | Yes, thank you!
        
             | rml wrote:
             | automatic conversion to web page available at
             | https://ar5iv.labs.arxiv.org/html/2302.07211
             | 
             | (more info about the conversions at
             | https://ar5iv.labs.arxiv.org)
        
               | eternalban wrote:
               | TIL. Thank you for this.
               | 
               | https://ar5iv.labs.arxiv.org/
        
         | lixtra wrote:
         | The first half page finally made me understand the problem. I
         | didn't get it from the article.
        
           | n4r9 wrote:
           | The statement in the article:
           | 
           | > a limit on the size of a set of integers in which no three
           | of them are evenly spaced
           | 
           | This misses a key detail. You can trivially find arbitrarily
           | large such sets e.g. take the first however many powers of 2:
           | 1, 2, 4, 8, 16 ...
           | 
           | The missing constraint is that the set of integers must be a
           | subset of { 1, 2, ... , N }.
        
             | monktastic1 wrote:
             | I thought it was pretty clear from this:
             | 
             | > Erdos and Turan wanted to know how many numbers smaller
             | than some ceiling N can be put into a set without creating
             | any three-term arithmetic progressions.
        
         | charlieyu1 wrote:
         | [flagged]
        
           | Ar-Curunir wrote:
           | What nonsense. Would you have even heard of this paper if not
           | for Quanta?
           | 
           | Also, no mathematician or computer scientist I know has
           | anything negative to say about Quanta.
        
             | pmezard wrote:
             | I do not really understand the unconditional love for
             | Quanta. Sure it is better it exists than not but I find the
             | articles vague and mostly about people/institution name
             | dropping. "Someone someone from the prestigious MIT said
             | <this is a tremendous result!>". Cool I guess?
             | 
             | Take this one:
             | 
             | - No clear explanation of the problem to solve. Could have
             | given an example or something to hammer out what is an
             | arithmetic progression of 3 numbers. - No detail about the
             | actual form of the previous bound and the new one. - Not
             | much detail about the actual technique. I get that it
             | become very technical very quickly. But that is the actual
             | job of a science/math journalist to distill this. "They
             | used a well know technique of increasing density, etc.". If
             | it is well know, why not try to describe how it works.
             | 
             | I wonder what someone like 3blue1brown would make of this.
        
               | impendia wrote:
               | > I wonder what someone like 3blue1brown would make of
               | this.
               | 
               | Although I am not Grant Sanderson (3blue1brown creator),
               | I would wager very good money that he would strongly
               | approve.
               | 
               | I am a research mathematician, I do read Quanta, and I've
               | been interviewed for them also. Overall my impression is
               | that they do a good job of making at least _something_ of
               | contemporary research mathematics accessible to the
               | general public. Most people have _very_ little concept of
               | what we do.
               | 
               | It is a notoriously hard task, it is a vitally important
               | one, and it is one that too few people are attempting.
               | Quanta does the best job of it of any publication I know,
               | and for that I am very grateful.
        
           | compacct27 wrote:
           | True, but we wouldn't be discussing this without the
           | journalism in the first place
        
       | bennysonething wrote:
       | Please stop with the click bait headlines :(
        
         | perihelions wrote:
         | "Theorem shows how 3-term arithmetic progressions inevitably
         | arise in large sets"
         | 
         | "Improved upper bound on density of integer sets containing no
         | subset a,a+b,a+2b"
        
         | tines wrote:
         | Did you read the article? The headline is pretty accurate, if
         | not pretty abstract.
        
           | colechristensen wrote:
           | It's click bait because it contains zero information about
           | what was actually done.
        
             | permo-w wrote:
             | it may be clickbait but it does provide information about
             | the crossing over of fields, which is interesting,
             | particularly when those fields are computer science and
             | maths
        
             | [deleted]
        
             | yborg wrote:
             | It's only bait if you bite on it, as you did. I did as
             | well, because I could see it was a Quanta link, and found
             | it quite interesting. Would I have clicked on it if the
             | title was "The Kelley--Meka bounds for sets free of three-
             | term arithmetic progressions?" Probably not. So in this
             | case, I consider myself fortunately baited.
        
               | phendrenad2 wrote:
               | So wait, you're saying that people should just accept
               | that headlines are uselessly hyperbolic, and either (A)
               | click every one of them to see if they're worth your time
               | or (B) never click any, to avoid "biting" and getting
               | "baited"?
               | 
               | Eminently practical approach, but we can hope for a
               | better world where this isn't necessary...
        
               | yborg wrote:
               | It seems that there is actually (C) somewhere in there,
               | which would be "apply some judgement" i.e. look at the
               | source, and maybe (D) let someone else on HN bite on it
               | and get a synopsis there.
        
               | permo-w wrote:
               | i feel like you've lost sight of what "bait" is
        
         | dang wrote:
         | Ok, we've unstunned the mathematicians and added combinatorics
         | to the title above.
        
         | TylerE wrote:
         | Any headline containing the word "bombshell", "destroys",
         | "shocking" or things of that ilk are ALWAYS poorly written
         | fluff, because editors are generally competent.
         | 
         | If there was an actual bombshell that would be the headline!
         | 
         | It wouldn't be "Surprise Computer Science Proof Stuns
         | Mathematicians" it would be "Scientist solves Fermat's Last
         | Theorem" or something
        
           | permo-w wrote:
           | this is actually untrue. yes it's a decent signal of
           | bollocks, but this is a perfectly interesting and well-
           | written article
           | 
           | those headlines and similar clickbait techniques are
           | annoying, but they're seen as a necessary evil by plenty of
           | "good quality" content creators and editors
           | 
           | this is especially evident on youtube, where it appears as if
           | you literally cannot gain mass success without surprising
           | facial expressions in your video thumbnails
           | 
           | if you think I'm exaggerating, open Youtube in a private tab
           | and see how many of the recommended videos _don't_ have
           | someone pulling an unusual facial expression in them
           | 
           | plenty of these videos are of perfectly good quality, but in
           | order to succeed they have to follow a shadowy pattern
        
           | Ar-Curunir wrote:
           | I mean, this is a pretty big result in combinatorics, solving
           | a 70-yr old problem.
        
             | TylerE wrote:
             | Then the head line should have said "combinatorics" instead
             | of the off-brand Buzzfeed "stuns mathematicians".
        
           | zamadatix wrote:
           | I always thought a set of satirical articles like "Mayor
           | Slams Opponents on Support of Budget Cuts" which then go into
           | said mayor being in custody for assault charges or other
           | similarly overly literal interpretations of the original
           | meaning would be good fun. Well, it probably exists I just
           | haven't seen them yet :).
           | 
           | It's great headlines aren't using the overly technical
           | description (that honestly doesn't help much either) but it
           | is a bit depressing the reason for doing so is "nobody clicks
           | those" not "it could be made clearer to the average person"
           | so we end up with things that are so vague you have no clue
           | what it could actually be about yet is written to ensure it
           | should be interesting enough for you to click. After that
           | they don't really care what you get out of it, you've loaded
           | another article and ads instead of leaving. This article
           | actually bucks the trends a bit by being decent enough with
           | what content is in the body at least.
        
           | tines wrote:
           | I mean, not every big result is FLT. This headline actually
           | tells me, a non-mathematician, much more than something more
           | accurate like "Strong Bounds for 3-Progressions". I have no
           | context for interpreting that phrase at all, but I can
           | appreciate the one chosen (if it's true, which it is).
        
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