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OpenCiv3: Open-source, cross-platform reimagining of Civilization III

https://openciv3.org/
624•klaussilveira•12h ago•182 comments

The Waymo World Model

https://waymo.com/blog/2026/02/the-waymo-world-model-a-new-frontier-for-autonomous-driving-simula...
926•xnx•18h ago•548 comments

What Is Ruliology?

https://writings.stephenwolfram.com/2026/01/what-is-ruliology/
32•helloplanets•4d ago•24 comments

How we made geo joins 400× faster with H3 indexes

https://floedb.ai/blog/how-we-made-geo-joins-400-faster-with-h3-indexes
109•matheusalmeida•1d ago•27 comments

Jeffrey Snover: "Welcome to the Room"

https://www.jsnover.com/blog/2026/02/01/welcome-to-the-room/
9•kaonwarb•3d ago•7 comments

Unseen Footage of Atari Battlezone Arcade Cabinet Production

https://arcadeblogger.com/2026/02/02/unseen-footage-of-atari-battlezone-cabinet-production/
40•videotopia•4d ago•1 comments

Show HN: Look Ma, No Linux: Shell, App Installer, Vi, Cc on ESP32-S3 / BreezyBox

https://github.com/valdanylchuk/breezydemo
219•isitcontent•13h ago•25 comments

Monty: A minimal, secure Python interpreter written in Rust for use by AI

https://github.com/pydantic/monty
210•dmpetrov•13h ago•103 comments

Show HN: I spent 4 years building a UI design tool with only the features I use

https://vecti.com
322•vecti•15h ago•143 comments

Sheldon Brown's Bicycle Technical Info

https://www.sheldonbrown.com/
369•ostacke•18h ago•94 comments

Microsoft open-sources LiteBox, a security-focused library OS

https://github.com/microsoft/litebox
358•aktau•19h ago•181 comments

Hackers (1995) Animated Experience

https://hackers-1995.vercel.app/
477•todsacerdoti•20h ago•232 comments

Show HN: If you lose your memory, how to regain access to your computer?

https://eljojo.github.io/rememory/
272•eljojo•15h ago•160 comments

An Update on Heroku

https://www.heroku.com/blog/an-update-on-heroku/
402•lstoll•19h ago•271 comments

Dark Alley Mathematics

https://blog.szczepan.org/blog/three-points/
85•quibono•4d ago•20 comments

Vocal Guide – belt sing without killing yourself

https://jesperordrup.github.io/vocal-guide/
14•jesperordrup•2h ago•6 comments

Delimited Continuations vs. Lwt for Threads

https://mirageos.org/blog/delimcc-vs-lwt
25•romes•4d ago•3 comments

Start all of your commands with a comma

https://rhodesmill.org/brandon/2009/commands-with-comma/
3•theblazehen•2d ago•0 comments

PC Floppy Copy Protection: Vault Prolok

https://martypc.blogspot.com/2024/09/pc-floppy-copy-protection-vault-prolok.html
56•kmm•5d ago•3 comments

Was Benoit Mandelbrot a hedgehog or a fox?

https://arxiv.org/abs/2602.01122
12•bikenaga•3d ago•2 comments

How to effectively write quality code with AI

https://heidenstedt.org/posts/2026/how-to-effectively-write-quality-code-with-ai/
244•i5heu•15h ago•188 comments

Introducing the Developer Knowledge API and MCP Server

https://developers.googleblog.com/introducing-the-developer-knowledge-api-and-mcp-server/
52•gfortaine•10h ago•21 comments

I spent 5 years in DevOps – Solutions engineering gave me what I was missing

https://infisical.com/blog/devops-to-solutions-engineering
140•vmatsiiako•17h ago•62 comments

Understanding Neural Network, Visually

https://visualrambling.space/neural-network/
280•surprisetalk•3d ago•37 comments

I now assume that all ads on Apple news are scams

https://kirkville.com/i-now-assume-that-all-ads-on-apple-news-are-scams/
1058•cdrnsf•22h ago•433 comments

Why I Joined OpenAI

https://www.brendangregg.com/blog/2026-02-07/why-i-joined-openai.html
132•SerCe•8h ago•117 comments

Show HN: R3forth, a ColorForth-inspired language with a tiny VM

https://github.com/phreda4/r3
70•phreda4•12h ago•14 comments

Female Asian Elephant Calf Born at the Smithsonian National Zoo

https://www.si.edu/newsdesk/releases/female-asian-elephant-calf-born-smithsonians-national-zoo-an...
28•gmays•7h ago•11 comments

Learning from context is harder than we thought

https://hy.tencent.com/research/100025?langVersion=en
176•limoce•3d ago•96 comments

FORTH? Really!?

https://rescrv.net/w/2026/02/06/associative
63•rescrv•20h ago•22 comments
Open in hackernews

Almost all Collatz orbits attain almost bounded values

https://mathvideos.org/2023/terence-tao-almost-all-collatz-orbits-attain-almost-bounded-values/
96•measurablefunc•2mo ago

Comments

throwaway81523•2mo ago
youtube link https://youtu.be/k-dtx8s2ehM
tux3•2mo ago
The paper (2019): https://arxiv.org/abs/1909.03562
noduerme•2mo ago
Does this have some significance for back propagation or something, or is it just an interesting trick of arithmetic? //not that it needs to have a technical use, it's still neat.
huhtenberg•2mo ago
Hailstone numbers has been a popular subject in computing circles since forever. Not much practical application, just a very simple, but curious construct.
robot-wrangler•2mo ago
Collatz, busy-beavers, and algorithmic information theory are all related. To the extent they offer insight into the sparseness or density of irreducible complexity in the space of all computation.. this has many implications for what can be computed efficiently, what can be learned efficiently, program-synthesis, what can be analyzed "at a distance" without just trying it and potentially needing to wait forever, etc.

Whether it will say anything very significant practically or only philosophically is a different question. Maybe it is something like the discovery of transcendentals.. finding out that most of the number line won't have a tidy algebraic closed-form isn't exactly a make-or-break deal for the program of mathematics itself, and it also doesn't matter much to people who are doing engineering

ur-whale•2mo ago
> Does this have some significance for back propagation or something

You're right!

What could darn possibly matter these days, in the whole entirety of the realm Mathematics, if it does now somehow have a measurable impact on backprop ?

WhyOhWhyQ•2mo ago
This guy's kid hits a homerun in the little league game and he bemoans that the kid is wasting his talents not working on backprop.
noduerme•2mo ago
Sigh. You're making the wrong assumption about why I asked the question.
Dylan16807•2mo ago
Asking because you think everyone else is so focused on AI that "high level of interest" implies AI is just as bad, probably worse.
noduerme•2mo ago
I'm not saying otherwise. I'm a bit tired of the subject dominating the front page (and every industry conversation, and the news). Ten years ago, I would have asked with some suspicion "does this relate to blockchain?" Sign of the times. Just as bad as what, personally only being interested in something if it relates to the hot topic of the day? I asked a genuine question, without leaping to any conclusions about the OP. Seems everyone leapt to the conclusion about me which I refrained from.
Dylan16807•2mo ago
Well I'm not leaping to conclusions, I'm going on the reason you said you asked.

> Just as bad as what, personally only being interested in something if it relates to the hot topic of the day?

On topics that don't inherently suggest any AI application, asking about AI applications from an AI-cynical perspective is even worse than asking from an AI-hype perspective. They both suck even if they're genuine, and the cynicism pushes it a little bit further.

noduerme•2mo ago
The cynicism is just asking what the underlying motive is [for the interest in this algorithm]. Whatever metric you're using for judging an honest question as "better" or "worse", you didn't answer the question (someone else did), you misinterpreted it, and you still feel the need to judge its validity. Whatever reasons you have for doing so and then trying to turn it into a morality play or a spectacle, as in, how dare you ask if this relates to back propagation? Oh it's even worse than I thought! - all of that calls your motivation into doubt and brings up a whole galaxy of questions as to why you'd find it necessary to attack someone for asking a plain technical question. None of which I care about kmowing the answers to.

At school they say: There are no stupid questions, only stupid answers. Consider what negative value you have brought to this conversation, without providing any insight whatsoever.

Dylan16807•2mo ago
> you didn't answer the question (someone else did), you misinterpreted it

> doing so and then trying to turn it

Do you have me confused with someone else? I did not reply until after you said why you asked. I didn't misinterpret anything.

I'm not trying to do any sneaky redirection. I just think it's bad to bring up AI on non-AI topics!

> At school they say: There are no stupid questions, only stupid answers. Consider what negative value you have brought to this conversation, without providing any insight whatsoever.

You said you dislike the AI dominating the front page, right?

You're contributing to that when you ask questions like the above.

Questions are usually good but sometimes a question is so off-topic that it detracts from the conversation.

phyzome•2mo ago
Crazy how AI has infected every conversation these days.
noduerme•2mo ago
I was just asking because I wondered if the high level of interest here was due to a connection with AI, not because I'm an AI evangelist. I tend to agree with you.
tromp•2mo ago
The closely related function Col' which also divides 3n+1 by 2 in the odd case, is concisely represented by the 65-bit lambda calculus term λ1(λλλ31(λλ2(421)))(λλ1)1(λλ1) operating on Church numerals [1]. It starts from the pair of numbers n and 0 and then performs n iterations of swapping the numbers after incrementing the first. Its lambda diagram is

    ┬───────────────┬──
    │ ┬────────── ─ │ ─
    │ ┼─────┬──── ┬ │ ┬
    │ ┼─┬───┼──── │ │ │
    │ └─┤ ┬─┼─┬── │ │ │
    │   │ ┼─┼─┼─┬ │ │ │
    │   │ │ └─┤ │ │ │ │
    │   │ │   ├─┘ │ │ │
    │   │ ├───┘   │ │ │
    │   ├─┘       │ │ │
    └───┤         │ │ │
        └─────────┤ │ │
                  └─┤ │
                    └─┘
[1] https://github.com/tromp/AIT/blob/master/fast_growing_and_co...
measurablefunc•2mo ago
Does it terminate for all n?
tromp•2mo ago
Yes; the Col' function trivially terminates for all n, since Col n' is just

    (if odd n then 3*n+1 else n) `div` 2
measurablefunc•2mo ago
That's good then. It shouldn't difficult to bootstrap that to the full Collatz conjecture.
tromp•2mo ago
Since the Collatz conjecture is not (known to be) finitely refutable, we cannot encode it as a program whose termination decides the conjecture. If the existence of diverging orbits were disproven though, then we could.
measurablefunc•2mo ago
That's a good point & also surprising that such a simple dynamical process can not be proven one way or the other to be an instance of a terminating or non-terminating computation.
im3w1l•2mo ago
I thought that diagram was giving me crazy strong synaesthesia, but turns out it was subpixel rendering and it really did have color.
anonymous2024•2mo ago
Someone has also noticed another curiosity: The number of bits of the biggest number (in binary notation) in a path is less than the number of bits of the initial number (in binary notation) * 3 + 1
tromp•2mo ago
If that were true, then every number would lead to a cycle (possibly a different one from 1-4-2). It would make the decision problem (whether a given initial number leads to 1) decidable, and the Collatz conjecture finitely refutable.
wizzwizz4•2mo ago
This isn't true. Take 9_A = 1001_2. 28_A = 11100_2, which is 5 bits long (3 set). The biggest number in this path is 52_A = 110100_2, which is 6 bits long (3 set). 5 ≯ 6, and 3 ≯ 3: neither of my interpretations of your statement holds.
taberiand•2mo ago
Not to say their statement is true but I don't see any reason to count the initial zeroes.

11100 == 111 == 11100000000, in terms of the next odd iteration

Even numbers don't really count in the process surely? All collatz does is essentially ignore those zeroes

wizzwizz4•2mo ago
Valid point: it depends what invariants you're trying to construct. Considering only the odd elements of the sequence does yield a slightly different set of insights compared to other approaches. (9 / 28 / 52 still describe a counterexample to the proposed invariant, even in this scheme.)
fhars•2mo ago
There is another interpretation, reading "bits" as "set bits" and assuming that textual description (especially the operator "of the") has a higher precedence than multiplication, then your initial number is 9 with 2 bits set, and the largest number is 52 with 3 bits set, and 3 < 2 * 3 + 1 = 7.
anonymous2024•2mo ago
What I understood was: 9_A = 1001_2 needs 4 bits, set or not set as the minimum length of the binary representation. 52_A = 110100_2 needs 6 bits 6 bits is less than 4*3+1=13 bits
wizzwizz4•2mo ago
At that point, the conjecture's just numerology: 27 takes 5 bits, and 9232 takes 14 bits (two shy of 3×5+1 = 16). 27 is the peak of the average ratio between start and maximum, because the +1s are so significant when the numbers are small: past that point, we're relying on extreme outlier behaviour to get each new high-score. Those only start showing up often enough to matter once we get into the thousands.

Plugging in values from OEIS A006884, it looks like the maximum ratio between the maximum and starting values goes down until around 4255, then picks up again, gradually increasing from there. Eyeballing the growth rate, I suspect there's a counterexample to this interpretation somewhere before 10^1000. (Does anyone have an element of A006884 greater than 2358909599867980429759? That's 140 bits maximum to 71 bits starting.)

littlestymaar•2mo ago
Do you have a source for that?
exomonk•2mo ago
In case people don't know the Collatz Conjecture, It's based on a simple rule: take any natural number n. If it is even, divide it by 2. If it is odd, multiply by 3 and add 1. The conjecture states that no matter what number you start with, you will eventually reach the number 1.

It would seem simple, but many simple iterative calculations get us to Turing machine territory regarding computability.

keepamovin•2mo ago
It's like gravity, collisions, and interstellar objects. Some starting points escape and go on ... forever.

Some kind of structure there that Collatz probing is sketching

apetresc•2mo ago
Except the Collatz Conjecture is almost certainly true, and there are no starting points that go on forever. Or did I miss the point of the analogy?
keepamovin•2mo ago
No you didn't misunderstand, I think. I thought there were some values that went on forever!

edit: however we could consider the weaker definition of "forever", and consider there are some outliers that go on "for a long time" per post title, probing structure with these loops and spokes. :D

sfblah•2mo ago
The conjecture is that there are no values that go on forever, but it's as yet unproven.
keepamovin•2mo ago
There probably are some very large values that go on forever. It's interesting how the structure of numbers must change at some point. Seemingly just based on magnitude, but in huge scales, some kind of density of structures related to factors builds up and eventually hits a critical point. And "island of forever". Collatz island, above what we've tested. It will be cool to discover that. I wonder how big it is? Probably hundreds of millions of decimal digits. But it's likely dense enough that if you randomly search and land on the island, you probably have a good chance.
madars•2mo ago
Good background reading/watching - Terence Tao's "The Notorious Collatz conjecture" talk. https://www.youtube.com/watch?v=X2p5eMWyaFs Slides: https://terrytao.wordpress.com/wp-content/uploads/2020/02/co...

I especially like how he highlights that Collatz conjecture shows that a simple dynamical system can have amazingly complex behavior; also 3n-1 variant has two known cycles - so "any proof of the Collatz conjecture must at some point use a property of the 3n+1 map that is not shared by the 3n-1 map." And this property can't be too general either - questions about FRACTRAN programs (of which Collatz conjecture is a special case) can encode the halting problem.

If you haven't seen it, FRACTRAN itself is amazing - https://www.cs.unc.edu/~stotts/COMP210-s23/madMath/Conway87.... and the paper is pure joy to read.

Xcelerate•2mo ago
As a non-mathematician, I’m confused why so many people think the conjecture (whether true or false) is provable within PA. To me, it seems like something that would be very nicely just right outside the boundary of PA’s capability, sort of like how proving all Goodstein sequences terminate requires transfinite induction up to ε_0. Add that to the fact that the Collatz Conjecture seems to fall in the same “category” of problem as the Turing machines that the Busy Beaver project is having a hard time proving non-halting behavior of, and the heuristic arguments all seem to point to: Collatz is independent of PA.

But I’m interested in hearing the counterarguments that Collatz likely is provable within PA and why this would be the case.

throwaway81523•2mo ago
The Collatz conjecture is "obviously" (i.e. probabalistically) true, so it's frustrating to not be able to turn that into a proof. PA doesn't matter, there's no known approach to proving it with stronger theories either. Of course many other propositions like the twin prime conjecture are in the same situation.

Goodstein's theorem by contrast is obviously provable in slightly stronger theories than PA, and it involves a fast-growing sequence which suggests it's out of weaker theories' reach. In fact it encodes ordinals up to eps_0 in a natural way, so its equivalence to CON(PA) is unsurprising. The Collatz conjecture is nothing like that. It's beguilingly simple by comparison.