[HN Gopher] Who Can Understand the Proof? A Window on Formalized...
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       Who Can Understand the Proof? A Window on Formalized Mathematics
        
       Author : ColinWright
       Score  : 162 points
       Date   : 2025-01-10 12:21 UTC (10 hours ago)
        
 (HTM) web link (writings.stephenwolfram.com)
 (TXT) w3m dump (writings.stephenwolfram.com)
        
       | francasso wrote:
       | Is there a relation between the "single axiom for boolean
       | algebra" that Wolfram claims to have discovered and the fact that
       | you can express all boolean operations with just NAND?
        
         | ur-whale wrote:
         | > Is there a relation between the "single axiom for boolean
         | algebra" that Wolfram claims to have discovered and the fact
         | that you can express all boolean operations with just NAND?
         | 
         | Seems to be partially answered in the article.
         | 
         | Search for "Is There a Better Notation?"
        
         | markisus wrote:
         | I was sort of puzzled by the meaning of "axiom for boolean
         | algebra" as well, and I looked into this more.
         | 
         | The way I learned boolean algebra was by associating certain
         | operations (AND, NOT, OR, etc) to truth tables. In this
         | framework, proving a theorem of boolean algebra would just
         | involve enumerating all possible truth assignments to each
         | variable and computing that the equation holds.
         | 
         | There is another framework for boolean algebra that does not
         | involve truth tables. This is the axiomatic approach [1]. It
         | puts forth a set of axioms (eg "a OR b = b OR a"). The symbol
         | "OR" is not imbued with any special meaning except that it
         | satisfies the specified axioms. These axioms, taken as a whole,
         | _implicitly_ define each operator. It then becomes possible to
         | prove what the truth tables of each operator must be.
         | 
         | One can ask how many axioms are needed to pin down the truth
         | table for NAND. As you know, this is enough to characterize
         | boolean algebra, since we can define all other operators in
         | terms of NAND. It turns out only one axiom is needed. It is
         | unclear to me whether this was first discovered by Wolfram, or
         | the team of William McCune, Branden Fitelson, and Larry Wos.
         | [2]
         | 
         | [1] https://en.wikipedia.org/wiki/Boolean_algebra_(structure)
         | 
         | [2] https://en.wikipedia.org/wiki/Minimal_axioms_for_Boolean_al
         | g...,.
        
           | jarpschope wrote:
           | Thanks for the wonderful explanation brother!
        
           | rramadass wrote:
           | Nice comment explaining the difference between two
           | viewpoints.
           | 
           | The former one is set theoretic i.e. set of objects (eg.
           | terms) and operations (eg. and/or/not) defined on those
           | objects. The latter is an algebraic specification where a
           | number of properties (expressed by logical formulas which can
           | be axioms or theorems) are expected to be satisfied by the
           | operations.
           | 
           | Also see https://en.wikipedia.org/wiki/Minimal_axioms_for_Boo
           | lean_alg...
           | 
           | PS: I would take any claim by Stephen Wolfram as having been
           | "the first" to discover anything with a boatload of salt.
        
         | Tainnor wrote:
         | The latter is a necessary, but not sufficient condition for the
         | former.
        
       | ur-whale wrote:
       | Here's a meta question about this article: let's try to estimate
       | how many people on earth, say within the next 5 years will ever
       | read the entire article in all of its gory details?
       | 
       | These days, an LLM will, perhaps.
       | 
       | An make it palatable to puny humans.
        
         | philipwhiuk wrote:
         | Or maybe it will fail to recall all of it and make something
         | up. Because it has 300B parameters not infinitely many.
         | 
         | We currently pull out our phones at the pub/table to check
         | something someone makes up to see if it's legitimate. Now we've
         | invented the technology to have something be that thing that
         | creates a half-truth from what it has absorbed.
        
         | astrange wrote:
         | Just train the LLM search engine to tell people it contains the
         | answers to all their questions.
        
         | queuebert wrote:
         | I probably could, but I'm 99% sure it's a thinly veiled self
         | promotion, as is usual from him.
        
       | cjfd wrote:
       | What is this central dot? I thought a central dot in boolean
       | logic means logical and but then the axiom is clearly false.....
       | I don't get what this is about.
        
         | ur-whale wrote:
         | > What is this central dot?
         | 
         | Yeah, I wish he had started by defining that. The is hard to
         | understand without it.
         | 
         | Search for "Is There a Better Notation?" in the article, it
         | seems "." is NAND
        
           | hulium wrote:
           | Technically, his axiom is the definition for what the
           | operator is. Any set together with an operator "*" that
           | satisfies this law is a boolean algebra. Binary logic where
           | *=NAND is one such example because it satisfies the axiom.
        
           | NooneAtAll3 wrote:
           | it's simply "Generic Operator". The only requirements is to
           | follow axioms for all its input values.
           | 
           | NAND isn't THE operator, it is AN operator that can be in
           | that place.
           | 
           | If there's only 1 value that variables can be - "I", then "I
           | \dot I = I" would be a valid operator that follows given
           | axioms
        
         | larschdk wrote:
         | The source uses *, not *, for the NAND operation.
        
         | BetterWhisper wrote:
         | In "The proof as we know" section he states that the dot is a
         | NAND operation
         | 
         | Quote: "the * dot here can be thought of as representing the
         | Nand operation"
        
         | Tainnor wrote:
         | As others have already said, think of it as NAND, although in
         | traditional logic this is typically called the "Sheffer
         | stroke".
        
         | etwas wrote:
         | The dot is not simply NAND or NOR.
         | 
         | Search for "What Actually Is the "*"?" for the answer, it's
         | quite complex and fascinating.
        
           | bo1024 wrote:
           | I was not able to find anything, can you help with locating
           | what you're talking about?
        
         | NooneAtAll3 wrote:
         | the whole point of this discipline is that this dot is simply a
         | "generic Operator"
         | 
         | you can use whatever symbol you want
         | 
         | all you really know - is the axiom you're given, which
         | transforms one tree structure of operator application into a
         | different one
         | 
         | NAND suggested in replies isn't THE operator, it's AN operator
         | that follows given rules
        
       | robertkoss wrote:
       | As someone who is completely unrelated to the academic world, is
       | Stephen Wolfram actually working on meaningful things? I remember
       | reading an article where he was announcing his Physics Project
       | which got a lot of backlash from the scientific community (at
       | least I think that was the case).
       | 
       | Nonetheless, every time I browse through Wolfram Alpha I am
       | thoroughly impressed of what it can do with only Natural Language
       | as an input.
        
         | meltyness wrote:
         | They've got a YouTube with pretty robust updates. Iirc, during
         | the lock downs, he'd do live coding and stuff.
        
         | pvg wrote:
         | https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
        
           | Tainnor wrote:
           | That's weird, why does Stephen Wolfram gets some sort of
           | special treatment here that nobody else seems to get -
           | including people that are subject to much more common and
           | intense criticism (just the other day there were people
           | bitching about Trudeau, for example - or let's take Elon Musk
           | who is an asshat (IMHO, YMMV), is discussing that off-topic
           | when it comes to how he manages Twitter?).
           | 
           | The question "is Stephen Wolfram being taken seriously by the
           | mathematics community?" seems relevant as a question to gauge
           | whether one should spend time reading a very long article.
           | 
           | edit: an even more relevant analogy - is Mochizuki's big ego
           | irrelevant in a discussion about whether his proof of the abc
           | conjecture, that nobody understands and which he refuses to
           | explain properly, is correct?
        
             | pvg wrote:
             | Because it's highly repetitive and uninteresting,
             | especially in the context of an article that is not about
             | Wolfram. The mod exhortations are a consequence of the
             | repetitiveness rather than some special carveout. Other
             | things that get that repetitive get similar appeals.
        
               | Tainnor wrote:
               | 90% of content on HN is repetitive. "Unit tests suck",
               | "managers forcing return to the office are assholes",
               | "Fauci lied about Covid", ...
               | 
               | I've never seen a single of these things being called
               | out.
               | 
               | This is an article about a proof Stephen Wolfram claims
               | to have discovered. Somebody further upthread already
               | mentioned that this may not actually be true, or that the
               | credit at least should be shared.
        
               | pvg wrote:
               | 90% of everything is repetitive. The generic analogies
               | method is not really that useful in discussing the
               | specific thing you asked about.
               | 
               |  _I 've never seen a single of these things being called
               | out._
               | 
               | Happens all the time plus many repetitive things
               | constantly get moderated away by users and moderators.
               | The goal is a less boring messageboard, but it's
               | aspirational rather than perfectly achievable.
               | 
               | Edit: Ok, fine, let's do analogies. Imagine Elon Musk
               | started writing long, interesting, researched articles
               | about some topic, say, Chinese history. If every such
               | article got flooded with discussions about who does and
               | does not like Elon Musk and by how much, those would
               | start getting modbleatings too. This is what happened
               | except it wasn't Elon Musk but Stephen Wolfram and it
               | wasn't Chinese History and it started about a decade ago
               | (as you can see from the comment dates).
        
               | Tainnor wrote:
               | Maybe the reason why people keep calling out Stephen
               | Wolfram (and have been doing so for a decade) is because
               | he has a history of making grandiose claims that do not
               | always withstand closer scrutiny?
               | 
               | I'm not claiming that Stephen Wolfram is an idiot or that
               | nothing he writes is of value, but his ego clearly does
               | influence his judgement so it makes no sense to me to
               | claim that it is off-topic (in the way that, say, his
               | love life or his opinion on abortion would be).
               | 
               | Also this:
               | 
               | > Happens all the time plus many repetitive things
               | constantly get moderated away by users and moderators.
               | The goal is a less boring messageboard, but it's
               | aspirational rather than perfectly achievable.
               | 
               | No sorry, I've been on HN during the pandemic and I was
               | this close to quitting it forever. These things do _not_
               | get called out in any consistent fashion for many topics.
               | I 'm pretty sure a message board for people interested in
               | technology can handle a couple of "Wolfram sucks"
               | comments a year better than literally hundreds of angry
               | rants about a health advisor that doesn't even have any
               | relevance to anyone who isn't from the US.
        
               | pvg wrote:
               | _Maybe the reason why people keep calling out_
               | 
               | It's not about the reason, it's about the repetitiveness.
               | The boringness of the repetitiveness is one of the
               | organizing principles of HN. Also, people don't actually
               | 'keep calling out' this stuff - these moderator
               | interventions, specifically in the Wolfram case, have
               | been surprisingly effective. Many Wolfram-y articles have
               | neither moderation intervention or bad tangents.
               | 
               |  _These things do not get called out in any consistent
               | fashion for many topics._
               | 
               | You don't see everything, neither do other forum
               | participants, including the moderators. The fact that,
               | collectively, some boring and repetitive stuff is missed
               | doesn't imply we can all use more boring, repetitive
               | stuff.
        
               | Tainnor wrote:
               | > You don't see everything, neither do other forum
               | participants, including the moderators.
               | 
               | The stuff that I mentioned was really hard to miss.
               | 
               | The question OP asked was, essentially, "is Stephen
               | Wolfram actively contributing to the mathematical
               | community?". If you really think that this is off-topic
               | then... I don't know what to say.
        
               | queuebert wrote:
               | Wolfram is essentially the Fauci of physics.
        
         | mr_mitm wrote:
         | No. Even though Mathematica is arguably meaningful. It's very
         | popular with some scientists, and in many aspects it's a
         | respectable piece of software.
         | 
         | A few years ago Sean Carroll was hosting him on his podcast. It
         | was a bit surprising to me because Sean would never give a
         | crackpot the time of the day, and Wolfram is borderline in
         | crackpot territory IMHO, but not quite. He hasn't published
         | anything meaningful in a scientific journal in a long time as
         | far as I know.
        
           | ericbarrett wrote:
           | I am neither a mathematician nor a scientist, so I'm
           | unqualified to judge Wolfram's current theories* of physics
           | and computation. But my impression is that he remains quite
           | rigorous in his work, even if the path he's walking is far
           | from the main. And of course he's quite bombastic, which
           | always seems to raise hackles. In fact, the article on which
           | this discussion anchors is a great example of both.
           | 
           | * Ref: https://www.wolframphysics.org/technical-introduction/
           | The podcast with Sean Carroll that parent mentioned is also a
           | surprisingly accessible lay introduction, definitely worth a
           | listen.
        
           | empath75 wrote:
           | As far as I can tell, he's not a crackpot, and doesn't say
           | anything that isn't _true_, he just wastes a lot of time
           | going down dead ends, and relentlessly promotes himself.
           | 
           | Like all the stuff about Rule 30 that he writes _endlessly_
           | about is both true and about 1/100th as interesting as he
           | evidently thinks it is.
        
         | jlouis wrote:
         | Define "meaningful".
         | 
         | A lot of mathematics is about exploration. You look at some
         | system and try to figure out how it works. If you have a good
         | idea (conjecture), you try proving or disproving it. The goal
         | is to gain some understanding.
         | 
         | Once in a while, it turns out that exploration hits the gold
         | ore in the mine. You get something that applies to solving some
         | problem we've had for years. As an example, algebra was
         | considered meaningless for years. Then cryptography came along.
         | 
         | There are other good examples. Reed-Solomon coding relies on a
         | basis of finite fields.
         | 
         | The problem is we don't really know when we'll strike gold in
         | many cases. So people go exploring. It also involves humans,
         | and they can disagree on a lot of things. Stephen seems to run
         | into disagreements more often than the average researcher, at
         | least historically.
        
           | pepinator wrote:
           | Has he gained interesting understanding of anything?
        
         | j16sdiz wrote:
         | He is trying to do alternative theory of science.
         | 
         | It's like rewriting (and clarifying things here or there,
         | putting in new analogies, etc.. not just translating)
         | everything in Klingon, and creating new Klingon words while he
         | is doing that.
         | 
         | Sure this is "interesting" in academic sense. Good luck finding
         | a journal accept paper written in Klingon.
        
         | the__alchemist wrote:
         | His physics project is high risk, and probably wrong. But very
         | worth it. He's working on things outside what the physics
         | community is focused on. And there are incentives for them to
         | keep working the same angles. IMO you need outsiders to spark
         | progress in cases like this. I will continue reading his work
         | and progress.
         | 
         | I think, specifically, his vision is very different and radical
         | from other things I've seen, which you'd think would lend
         | itself to at least one currently-testable hypothesis, but I
         | haven't seen one. It seems there may overfitting. He has a way
         | for every major principle in physics to fit into his theory,
         | but no _new_ ones, or flaws in current ones; that 's what
         | worries me. I hope he continues working on it. (Unlikely he'll
         | stop after this many decades)
         | 
         | As a comparison, I'm more hopeful for this than String theory,
         | and the latter has been found worthy of physicist's time, so I
         | certainly think this is.
         | 
         | Regarding the _crackpot_ angle: I think that is not an
         | appropriate label: If you look at the people that the label
         | canonically applies to, you will find people who have no idea
         | what they 're talking about, who don't understanding the math
         | and physics etc. That is not the case here; he knows it as well
         | as anyone.
        
       | bmc7505 wrote:
       | Although Wolfram doesn't mention it by name, this is closely
       | related to what he is trying to do:
       | https://en.wikipedia.org/wiki/Reverse_mathematics
        
         | vasco wrote:
         | Wanted to thank you for the share, added "Reverse Mathematics:
         | Proofs from the Inside Out" to my reading list which was
         | referenced in the article you posted:
         | https://www.goodreads.com/book/show/34928283-reverse-mathema...
        
           | bmc7505 wrote:
           | Depending on how comfortable you are with model theory you
           | might also enjoy Dzhafarov and Mummert's textbook, which
           | first brought the subject to my attention.
        
       | sylware wrote:
       | Formal proof is so much important, since currently maths is built
       | on set theory, I wonder how the set theory axioms are written in
       | some of the formal solvers.
        
         | robinzfc wrote:
         | No need to wonder for long, just have a look.
         | 
         | Metamath: https://us.metamath.org/mpeuni/mmset.html#axioms
         | 
         | Isabelle/ZF:
         | https://isabelle.in.tum.de/dist/library/FOL/ZF/ZF_Base.html
        
         | gaogao wrote:
         | You can model types as a set and sets as types in many ways, so
         | a number of the basic set theory axioms are pretty simple to
         | express as lemmas from type axioms. IIRC you get constructive
         | set theory easy, but do have to define additional axioms
         | typically for ZFC.
        
         | luma wrote:
         | Check out mathlib for LEAN, the pace of proofs being added here
         | is breathtaking: https://github.com/leanprover-
         | community/mathlib4
        
         | staunton wrote:
         | > currently maths is built on set theory
         | 
         | most mathematicians will eventually agree with that when
         | pressed. However, almost none of them know the axioms of ZFC by
         | heart (because they don't need them). You can swap out ZFC for
         | something else and nobody will care very much as long as "the
         | same" (does a lot of work here) theorems, which they know and
         | use it their work, remain true.
         | 
         | This is what many theorem provers do. Many aren't based on set
         | theory, for example, but instead on type theory. (You can still
         | do set theory in a framework based on type theory, and vice
         | versa, but the foundations are "different").
        
       | agentultra wrote:
       | One of the perennial questions about proof automation has been
       | the utility of proofs that cannot be understood by humans.
       | 
       | Generally, most computer scientists using proof automation don't
       | care about the proof itself -- they care that one exists. It can
       | contain as many lemmas and steps as needed. They're unlikely to
       | ever read it.
       | 
       | It seems to me that LLMs would be decent at generating proofs
       | this way: so long as they submit their tactics to the proof
       | checker and the proof is found they can generate whatever is
       | needed.
       | 
       | However for mathematicians, of which I am not a member of that
       | distinguished group, seem to appreciate qualities in proofs such
       | as elegance and simplicity. Many mathematicians that I've heard
       | respond to the initial question believe that a proof generated by
       | some future AI system will not be useful to humans if they cannot
       | understand and appreciate it. The existence of a proof is not
       | enough.
       | 
       | Now that we're getting close to having algorithms that can
       | generate proofs it makes the question a bit more urgent, I think.
       | What use is a proof that _isn 't_ elegant? Are proofs written for
       | a particular audience or are they written for the result?
        
         | Davidbrcz wrote:
         | It depends.
         | 
         | A proven conjecture is IMO better than an unproven one.
         | 
         | But usually, a new proof would shed new lights or build bridges
         | between concepts that were before unrelated.
         | 
         | And in that sense, a proof not understandable by humans is
         | disappointing, because it doesn't really fullfil the need to
         | understand the reason behind why it's true.
        
         | crabbone wrote:
         | This isn't a new conundrum. This was a very contentious
         | question in the end of the 19th century, where French
         | mathematicians clashed with the German mathematicians. Poincare
         | is known for describing proofs as texts intended to convince
         | other mathematicians that something is the case, whereas
         | Hilbert believed that automation is the way to go (i.e. have a
         | "proof machine", plug in the question, get the answer and be
         | done with it).
         | 
         | Temporarily, Germans won.
         | 
         | Personally, I don't think that proofs that cannot be understood
         | have no value. We rely on such proofs all the time in our day-
         | to-day interpretation of the world around us, our ability to
         | navigate it and anticipate it. I.e. there's some sort of an
         | automated proof tool in our brains that takes the visual input,
         | feeling of muscle tonus, feeling of the force exerted on our
         | body etc. and then gives an answer as to whether we are able to
         | take the next step, pick up a rock and so on.
         | 
         | But, mathematicians also want proofs to be useful to explain
         | the nature of the thing in question. Because another thing we
         | want to do about things like picking up rocks, is we want to
         | make that more efficient, make inanimate systems that can pick
         | up rocks etc.
         | 
         | ----
         | 
         | NB. I'm not entirely sure how much LLMs can contribute in this
         | field. The first successes of AI were precisely in the field of
         | automated proofs, and that's where symbolic AI seems to work
         | great. But, I'm not at all an expert on LLMs. Maybe there's
         | some way I cannot think about that they would be better at this
         | task, but on the face of it they just aren't.
        
           | rocqua wrote:
           | From what I have heard when talking to the people behind
           | formal analysis of protocol security, the main problem
           | currently with using LLMs to 'interact with the theorem
           | prover for you' is that there is nowhere near enough proofs
           | out there for the LLMs to learn how to generalize from them.
        
         | chii wrote:
         | i would imagine a proof has several "uses": 1) the proof itself
         | is useful for some other result or proof, and 2), the proof is
         | using a novel technique or uses novel maths, or links to
         | previously unlinked fields, and it's not the proof's result
         | itself that is useful, but the technique developed. This
         | technique can then be applied in other areas to produce other
         | kinds of proofs or knowledge.
         | 
         | I suspect it is the latter that will suffer in automated proofs
         | perhaps - without understanding the techniques, or if the
         | technique is not really novel but just tedious.
        
         | knappa wrote:
         | Mathematician here (trained as pure, working as applied). Non-
         | elegant proofs are useful, if the result is important. e.g.
         | People would still be excited by an ugly proof of the Riemann
         | hypothesis.^1 It's important too a lot of other theorems if
         | this is true or not. However, if the result is less central you
         | won't get a lot of interest.
         | 
         | Part of it is, I think, that "elegance" is flowery language
         | that hides what mathematicians really want: not so much new
         | proofs as new proof techniques and frameworks. An "elegant"
         | proof can, with some modification, prove a lot more than its
         | literal statement. That way, even if you don't care much about
         | the specific result, you may still be interested because it can
         | be altered to solve a problem you _were_ interested in.
         | 
         | 1: It doesn't have to be as big of a deal as this.
        
           | The_suffocated wrote:
           | _" It doesn't have to be as big of a deal as this."_
           | 
           | Agree. The truthfulness of the four-colour theorem is good to
           | know, although there is not yet any human-readable proof.
        
             | rocqua wrote:
             | I feel like the four-color theorem automated proof is much
             | more 'human-readable' than the proofs done with automated
             | theorem provers. Because with the four-color theorem, there
             | is a human readable proof that says "if this finite set of
             | cases are all colorable, then all planar graphs are
             | colorable". And then there is some rather concrete code
             | that generates all the finite cases, and finds a coloring
             | for them. Every step in there makes sense, and is fully
             | understandable. The fact that the exhaustive checking
             | wasn't done by hand doesn't mean its hard to understand how
             | the proof works, or what is 'actually going on'.
             | 
             | For a general theorem prover, reading the code doesn't
             | explain anything insightful about why the theorem is true.
             | For the 4 color theorem, the code that proved it actually
             | gives insight in how the proof works.
        
           | LegionMammal978 wrote:
           | Then again, even an 'elegant' proof can be surprisingly
           | inflexible. I've recently been working through Apery's proof
           | that z(3) is irrational. It's so simple that even a clueless
           | dabbler like me can understand all the details. Yet no one
           | has been able to make his construction work directly for
           | anything else (that hasn't already been proven irrational).
           | C'est la vie, I suppose.
        
             | rocqua wrote:
             | There was a post yesterday of a quanta article:
             | https://news.ycombinator.com/item?id=42644896.
             | 
             | The article explains that two mathematicians were able to
             | place Apery's proof that z(3) is irrational into a much
             | wider (and hence more powerful) framework. I doubt that
             | framework is as easy to understand as the original proof.
             | But in the end something with wider applicability did come
             | out of the proof.
        
               | LegionMammal978 wrote:
               | Yeah, many of the fancy analytic methods are beyond my
               | level of dabbling. I've been trying to learn more about
               | them, so I can solve the myriad exercises left to the
               | reader in all the Diophantine approximation papers.
               | 
               | Still, the newer methods publicized in the Quanta article
               | definitely get more involved, and at least from my
               | perspective they don't establish things as elegantly as
               | Apery's z(2) and z(3) arguments do. Hopefully they turn
               | out to be powerful in practice, to make up for it.
        
           | User23 wrote:
           | One thing that many mathematicians today don't think about is
           | how deeply intertwined the field has historically been with
           | theology. This goes back to the Pythagoreans at least.
           | 
           | That survives in the culture of mathematics where we continue
           | to see a high regard for truth, beauty, and goodness. Which,
           | incidentally, are directly related to logic, aesthetics, and
           | ethics.
           | 
           | The value of truth in a proof is most obvious.
           | 
           | The value of aesthetics is harder to explain, but there's no
           | denying that it is in fact observably valued by
           | mathematicians.
           | 
           | As for ethics, remember that human morality is a proper
           | subset thereof. Ethics concerns itself with what is good. It
           | may feel like a stretch, but it's perfectly reasonable to say
           | that for two equally true proofs of the same thing, the one
           | that is more beautiful is also more good. Also, obviously,
           | given two equally beautiful proofs, if only one is true then
           | it is also more good.
        
             | Xcelerate wrote:
             | > That survives in the culture of mathematics where we
             | continue to see a high regard for truth, beauty, and
             | goodness
             | 
             | As a non-mathematician, I've noticed this as well, and I
             | have a suspicion the historical "culture" is holding the
             | field back. Godel proved there are an infinite number of
             | true arithmetic statements unprovable within any
             | (consistent, sufficiently powerful) formal system. But our
             | "gold standard" formal system, ZFC, has about as many
             | axioms as we have fingers -- why is finding more axioms not
             | the absolute highest priority of the field?
             | 
             | We struggle to prove facts about Turing machines with only
             | six states, and it's not obvious to me that ZFC is even
             | capable of resolving all questions about the behavior of
             | six state Turing machines (well, specifically just ZF, as C
             | has no bearing on these questions).
             | 
             | Yet Turing machines are about as far from abstract
             | mathematics as one can get, because you can actually build
             | these things in our physical universe and observe their
             | behavior over time (except for the whole "infinite tape"
             | part). If we can't predict the behavior of the majority of
             | tiny, _deterministic_ systems with ZFC, what does that say
             | about our ability to understand and predict real world
             | data, particularly considering that this data likely has an
             | underlying algorithmic structure vastly more complex than
             | that of a six state Turing machine?
             | 
             | More formally, my complaint with the culture of mathematics
             | is:
             | 
             | 1) We know that for any string of data, I(data : ZFC) <=
             | min(K(data), K(ZFC)) + O(1)
             | 
             | 2) K(ZFC) is likely no more than a few bytes. I think the
             | best current upper bound is the description length of a
             | Turing machine with a few hundred states, but I suspect the
             | true value of K(ZFC) is far lower than that
             | 
             | 3) Thus K(data) - K(data | ZFC) <= "a few bytes"
             | 
             | Consider the massive amounts of data that we collect to
             | train LLMs. The totality of modern mathematics can provide
             | no more than a few bytes of insight into the "essence" of
             | this data (i.e., the maximally compressed version of the
             | data). Which directly translates to limited predictability
             | of the data via Solomonoff induction. And that's _in
             | principle_ -- this doesn 't even consider the amount of
             | time involved. If we want to do better, we need more
             | axioms, full stop.
             | 
             | One might counter, "well sure, but mathematicians don't
             | necessarily care about real world problems". Ok, just apply
             | the same argument to the set of all arithmetic truths. Or
             | the set of unprovable statements in the language of a
             | formal system (that are true within some model). That's
             | some interesting data. Surely ZFC can discover most "deep"
             | mathematical truths? Not very likely. The deeper truths
             | tend to occur at higher levels of the arithmetic hierarchy.
             | The higher in the hierarchy, the more interesting the
             | statement. And these are _tiny_ statements too: [?]x [?]y
             | [?]z [...]. Well we 're already in trouble because ZFC can
             | only decide a small fraction of the P_2 statements that can
             | fit on a napkin and it drops off very quickly at higher
             | levels than that. Again, we need more axioms.
        
               | nyssos wrote:
               | > Yet Turing machines are about as far from abstract
               | mathematics as one can get, because you can actually
               | build these things in our physical universe and observe
               | their behavior over time (except for the whole "infinite
               | tape" part)
               | 
               | The infinite tape part isn't some minor detail, it's the
               | source of all the difficulty. A "finite-tape Turing
               | machine" is just a DFA.
        
               | Xcelerate wrote:
               | > is just a DFA
               | 
               | Oh is that all? If resource bounded Kolmogorov complexity
               | is that simple, we should have solved P vs NP by now!
               | 
               | I debated adding a bunch of disclaimers to that
               | parenthetical about when the infinite tape starts to
               | matter, but thought, nah, surely that won't be the
               | contention of the larger discussion point here haha
        
               | User23 wrote:
               | It's an LBA, a Linear Bounded Automata.
        
               | mb7733 wrote:
               | > > That survives in the culture of mathematics where we
               | continue to see a high regard for truth, beauty, and
               | goodness
               | 
               | > As a non-mathematician, I've noticed this as well, and
               | I have a suspicion the historical "culture" is holding
               | the field back.
               | 
               | Holding the field back from what? If the goal of the
               | practitioners of the field is to seek mathematically
               | beauty, then well, that is what they will focus on.
               | 
               | Besides that, I don't really follow your argument about
               | Godel & information theory & that adding more axioms is
               | the key to moving math forwards. In the vast majority of
               | cases, the difficulty in finding a proof of a statement
               | is not that the statement isn't provable under a given
               | formal system, it's that we simply can't find it. But
               | maybe I misunderstand you?
        
           | dataflow wrote:
           | > Part of it is, I think, that "elegance" is flowery language
           | that hides what mathematicians really want: not so much new
           | proofs as new proof techniques and frameworks. An "elegant"
           | proof can, with some modification, prove a lot more than its
           | literal statement. That way, even if you don't care much
           | about the specific result, you may still be interested
           | because it can be altered to solve a problem you _were_
           | interested in.
           | 
           | Do you feel this could be a matter of framing? If you view
           | the "proof" as being the theorem prover itself, plus the
           | proof that it is correct, plus the assumptions, then whatever
           | capability it gains that lets it prove your desired result
           | probably _is_ generalizable to other things you were
           | interested in. It would seem like a loss if they 're
           | dismissed simply because their scratch work is inscrutible.
        
         | QuesnayJr wrote:
         | I think mathematicians want something more basic, though
         | elegance and simplicity are appreciated. They want to know
         | _why_ something is true, in a way that they can understand.
         | People will write new proof of existing results if they think
         | they get at the  "why" better, or even collect multiple proofs
         | of the same result if they each get at the "why" in different
         | ways.
        
           | agentultra wrote:
           | In my limited experience it seems like the "why" of a proof
           | requires a _theory of mind_ from the perspective of the
           | author of the proof.
           | 
           | What I mean is that one could choose a particular tactic to
           | proving a lemma or even rely on certain lemma where that
           | choice is intended for the audience the author has in mind in
           | order to help them understand the steps better.
           | 
           | The _context_ an LLM uses is limited (though growing).
           | However its context is lacking the ability to understand the
           | mind of the interlocutor and the proof they would expect or
           | find helpful.
           | 
           | "Why this proof?" also has a more _global_ context as well.
           | It seems there are have been styles and shifts in cultural
           | norms over the years in proofs. Even though the Elements
           | stood up until the 19th century we don 't necessarily write
           | proofs in the style of Euclid even though we may refer to
           | those themes and styles, on purpose, in order to communicate
           | a subtle point.
        
         | flatline wrote:
         | Hypothesis: an LLM capable of generating a correct proof in a
         | formal language, not through random chance but through whatever
         | passes for "reasoning," should also be capable of describing
         | the proof in a way meaningful to humans. Because LLMs have a
         | limited context window and are trained on human behavior, they
         | will generate solutions similar to what humans would generate.
         | 
         | We have already accepted some proofs we cannot fully
         | understand, such as the proof of the four color theorem that
         | used computational methods to explore a large solution space
         | and demonstrate that no possible special-case combinations
         | violate the theorem. But that was just one part of the proof.
         | 
         | I wonder what we know about proof space generally, and if we
         | had an ASI that reasoned in a substantially different way than
         | humans, what types of proofs it would be likely to generate. Do
         | most proofs contain structural components that humans find
         | pleasing? Do most devolve into convoluted case analyses? Is
         | there a simplest form that a set of correct proofs could be
         | reduced to?
        
           | ndriscoll wrote:
           | To me this seems obvious. Copilot might generate _wrong_
           | things, but what I 've seen tends to be human-readable. My
           | experience with Lean is that it feels very much like a
           | functional programming language like Scala, so I'd have to
           | assume that a coding assistant that also knows Lean
           | syntax/libraries would work just like any other programming
           | language.
           | 
           | There will perhaps need to be a transition period where we
           | might need to look at basic type theory augmenting or
           | replacing material in introductory proof classes. Instead of
           | truth tables and ZFC, teach math-as-programming. Propositions
           | are types, implications are functions, etc. If you have the
           | right foundation, I think the stuff ends up being quite
           | legible. Mathlib is very abstract which makes it harder to
           | approach as a beginner, but you could imagine a sort of
           | literate programming approach where we walk students through
           | building their own personal Mathlib, refactoring it to use
           | higher abstractions as they build it up, etc. In a sense this
           | is what a math education is today, but with a kind of half-
           | formal, half-natural language and with a bunch of implicit
           | assumptions about what techniques the student really knows
           | (since details are generally omitted) vs. letting them use
           | whatever macros/tactics/theorems they've learned/created in
           | other courses.
           | 
           | This could all be especially powerful if the objects you're
           | working with have good Widgets[0][1] so you could visualize
           | and interact with various intermediate expressions. I see
           | tons of potential here. The Lean games[2] also show the
           | potential for a bright future here that's kind of along the
           | lines of "build your own library around topic X" (the NN game
           | has been posted here a few times, but it's actually a
           | framework with other games too!).
           | 
           | [0] https://lean-
           | lang.org/lean4/doc/examples/widgets.lean.html
           | 
           | [1] https://github.com/leanprover-
           | community/ProofWidgets4/blob/m...
           | 
           | [2] https://adam.math.hhu.de/
        
         | math-ias wrote:
         | I believe knowing a proof exists will bring us closer to
         | elegant human proofs.
         | 
         | I wanted to justify this with the "Roger Bannister Effect". The
         | thought is that we're held back psychologically by the idea of
         | the impossible. It takes one person to do it. And now everyone
         | can do it, freed from the mind trap. But further reading shows
         | we were incrementally approaching what Roger Bannister did
         | first: the 4 minute mile. And the pause before that record was
         | likely not psychological but physical with World War Two. [0]
         | And this jives with the TFA when Mr. Wolfram writes about a
         | quarter of a century not yielding a human interpretation of his
         | computer's output.
         | 
         | All I'm left with is my anecdotes. I had a math professor in
         | college who assigned homework every class. Since it was his
         | first time teaching, he came up with the questions live. I'd
         | come to class red in the face after struggling with questions
         | all night. Then the professor would sheepishly reveal some of
         | his statements were false. That unknown sapped a lot of
         | motivation. Dead ends felt more conclusive. Falsehood was an
         | easy scapegoat.
         | 
         | [0] https://www.scienceofrunning.com/2017/05/the-roger-
         | bannister...
        
           | QuesnayJr wrote:
           | I think there is something to this idea. There have been
           | cases where person A was working on proving a result but
           | struggled, then person B announced a proof of the result, and
           | then person A was inspired to finish their proof. (Sadly, I
           | don't remember the specifics.)
        
         | glenstein wrote:
         | >One of the perennial questions about proof automation has been
         | the utility of proofs that cannot be understood by humans.
         | 
         | I'm skeptical of an in-principle impossibility of understanding
         | complex proofs. I think computers likely will have, or already
         | do have, a capability for explaining proofs piecemeal, with
         | explanations that bridge from the proof itself to familiar
         | intuitions.
         | 
         | Needing to understanding by increasingly sophisticated bridge
         | explanations may be us getting further removed from immediate
         | understanding but I don't think it crosses a magical threshold
         | or anything that fundamentally calls into question how
         | operational/useful the proofs are.
        
         | youoy wrote:
         | An ugly proof is super useful. It turns a statement into a
         | theorem.
         | 
         | There is a famous quote by Riemann: "If only I had the
         | theorems! Then I should find the proofs easily enough. "
         | 
         | Once you have a proof, simplifying it should be much easier,
         | even for computers.
        
       | bumbledraven wrote:
       | > as we'll discuss, it's a basic metamathematical fact that out
       | of all possible theorems almost none have short proofs
       | 
       | Where in the article is this discussed?
        
         | Tainnor wrote:
         | For any possible definition of "short", there's only finitely
         | many (and typically few) theorems that have a short proof,
         | while there are infinitely many theorems (not all of them
         | interesting).
         | 
         | More in detail: Proofs are nothing more than strings, and
         | checking the validity of a proof can be done mechanically (and
         | efficiently), so we can just enumerate all valid proofs up to
         | length N and pick out its conclusion.
        
         | optimalsolver wrote:
         | >of all possible theorems almost none have short proofs
         | 
         | Ok, but what about the theorems humans would actually care
         | about?
        
       | coonjecture wrote:
       | Perhaps using Grobner basis for formal proofs [1],[2] could be
       | similar to what appears here, that is during the proof the length
       | of the terms (or polynomials) can grow and then at the end there
       | is a simplification and you obtain a short grobner basis (short
       | axioms).
       | 
       | A simple question, since * is nand, the theorem
       | ((a*b)*c)*(a*((a*c)*a))=c, can be proved trivially computing the
       | value of both sides for the 8 values of a,b,c. Also there are
       | 2^(2^2)=16 logic functions with two variables so is trivial to
       | verify that the theorem is valid iff * is nand. Perhaps the
       | difficulty is proving the theorem using rules?, there must be
       | something that I don't see (I just took a glimpse in a few
       | seconds).
       | 
       | Automatic formal proofs can be useful when you are able to test
       | [1] https://doi.org/10.1016/j.jpaa.2008.11.043 [2] https://ceur-
       | ws.org/Vol-3455/short4.pdf
        
         | supernewton wrote:
         | The thing you're missing is that at no point is it assumed that
         | there are exactly two elements in a boolean algebra. In fact
         | you can have a boolean algebra with four elements (see
         | https://en.wikipedia.org/wiki/Boolean_algebra_(structure)).
        
           | coonjecture wrote:
           | It seems the author is using the word logic, so logic boolean
           | algebra suggests the classical case. Perhaps what is not
           | trivial is that one can use that rule to deduce the other
           | axioms. So that is not the theorem what is important but that
           | one can prove any tautology using that simple axiom.
        
       | User23 wrote:
       | I wonder if he's familiar with Peirce's alpha existential graphs.
       | They are a complete propositional logic with a single axiom and,
       | depending how you count them, 3-6 inference rules. They use only
       | negation and conjunction.
       | 
       | They also permit shockingly short proofs compared to the
       | customary notation. Which, incidentally was also devised by
       | Peirce. Peano freely acknowledges all he did is change some of
       | the symbols to avoid confusion (Peirce used capital sigma and pi
       | for existential and universal quantification).
        
         | bwfan123 wrote:
         | Can you share a good reference to peirce's work on existential
         | graphs ? also, can you share references to how Peano relates to
         | Peirce's work.
         | 
         | I loved Peirce's essays, but have not tried to read his work on
         | logic or semiotics.
        
           | User23 wrote:
           | John Sowa is a good resource. Here is his annotation of
           | Peirce's tutorial[1]. Another paper explores the influence of
           | EG on Sowa's Conceptual Graphs[2]. I happen to find the
           | juxtaposition of Frege's notation with Peirce's interesting.
           | Sowa's commentary on yet another Peirce manuscript has some
           | fun historical tidbits about the influence of Peirce on the
           | design of SQL[3]. Here is another reference that mentions
           | Peano's adoption of Peirce's notation[4].
           | 
           | That should be plenty to get you started! Digging through the
           | references in those papers and the bibliography on Sowa's
           | site will find you plenty more modern Peirce scholarship. I
           | think Peirce would be pleased that his seemingly abstract
           | approach to logic ended up inspiring one of the most
           | pragmatically useful classes of software ever, the relational
           | database.
           | 
           | [1] https://www.jfsowa.com/pubs/egtut.pdf
           | 
           | [2] https://www.jfsowa.com/pubs/eg2cg.pdf
           | 
           | [3] https://www.jfsowa.com/peirce/csp1885.HTM
           | 
           | [4] https://www.jfsowa.com/pubs/csp21st.pdf
        
             | bwfan123 wrote:
             | thanks !
        
       | graycat wrote:
       | In proofs in math, there is the old: "Elegance is directly
       | proportional to what you can see in it and inversely proportional
       | to the effort it takes to see it."
        
       | sega_sai wrote:
       | I have not fully read the whole page, but I wonder if this type
       | of tree of expressions leading to a proof can be explored
       | efficiently with the same idea as Monte-Carlo Tree Search in
       | chess. I.e. surely you can explore all the possible combinations
       | of existing axioms/lemmas, but if you have something like NN, it
       | can suggest the most interested branches of the tree, so you can
       | go deeper in the tree/graph without exponential effort.
        
       | unkulunkulu wrote:
       | In the bisubstitution example, I cannot see the difference
       | between the source lemma and the target lemma. It looks like A=>A
       | proof. Am I blind?
        
       | philzook wrote:
       | It's interesting how sometimes it feels like a topic starts
       | showing up super often all of the sudden. It probably isn't a
       | coincidence, since my interest and probably this post's interest
       | is due to Tao's recent equation challenge
       | https://teorth.github.io/equational_theories/ .
       | 
       | I was surprised and intrigued to find Wolfram's name when I was
       | reading background literature doing this blog post
       | https://www.philipzucker.com/cody_sheffer/ where I translated my
       | friend's Lean proof of the correspondence of Sheffer stroke to
       | Boolean algebra in my python proof assistant knuckledragger
       | https://github.com/philzook58/knuckledragger (an easier result
       | than Wolfram's single axiom one).
       | 
       | I was also intrigued reading about the equational theorem prover
       | Waldmeister https://www.mpi-inf.mpg.de/departments/automation-of-
       | logic/s... that it may have been acquired by Mathematica? It's
       | hard to know how Mathematica's equational reasoning system is
       | powered behind the scenes.
       | 
       | Mathematica can really make for some stunning visuals. Quite
       | impressive.
        
       | ogogmad wrote:
       | It's probably nothing, but one of the pivotal lemmas is
       | (a|(a|(a|b))) = (a|b). Imagine replacing (a|b) with x to get
       | (a|(a|x)) = x; then this identity can be read as "x reflected
       | through 'a' twice gives x". It reminds me of O Loos's axiomatic
       | approach to Symmetric Spaces where the operation | means reflect.
       | It axioms are (x|x) = x; (x|(x|y)) = y; (x|(y|z)) =
       | ((x|y)|(x|z)); and finally that "|" should be a smooth function
       | over some manifold.
       | 
       | But then again, when "|" is NAND, it follows that (a|b)|(a|b)
       | means NOT (a|b), which breaks the apparent link to symmetric
       | spaces, because x reflected through itself should give back x.
        
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