Comment by stschaef
13 hours ago
This reads very vibecoded, but putting that aside...
1. How does this benefit from GPU parallelism? I don't know much about implementing proof assistant, as I am just a user, but its my understanding that these tasks aren't amenable to running on a GPU.
2. The comparison to Lean/Agda/Isabelle/etc have no meaning without understanding what programs are being used for comparison. I also so far have no reason to believe large-scale verified programs would ever adapt to Bend. For instance, I have a large software verification project written in Cubical Agda https://github.com/um-catlab/cubical-categorical-logic it's not clear to me how one would even begin to port this over to Bend, especially given the dependence on cubical
3. Single commit history is hella sus
4. Bend uses "an affine dependent type theory". Substructural dependent type systems are an active area of research. If this weren't slop, I'd expect such a system to be worthy of publication at a top programming languages conference. It sounds quite unlikely that a random vibecoded project with a Fable-written paper has worked out all of the kinks
5. I would've at least expected this paper to be cited https://arxiv.org/abs/2401.15258 but it is noticeably absent
I'm glad you're having fun vibecoding, and I like that you're interested in this area of research/engineering, but you are wildly overstating what you have here and sound sus af
Yes, there's a lot of vibe-coding in many places, but the critical parts (compiler, runtime, kernel) are human designed, and the kernel has been extensively audited by human. All of it is my own design and architecture, and I'm a human, I think. We'll prune AI slop over time. The project is big, and we're a small team.
1. The paper explains it well (sadly it is written by Claude for now, but it is accurate):
https://github.com/bendlang/bend/blob/main/paper/BendRT.pdf
In short, we implemented a complete allocator, garbage-collector, closure evaluator and functional evaluator, on the GPU (with zero interaction net overhead this time). We then use a very simple (for now) scheduler that spreads binary recursive calls as to saturate all CPU or GPU cores, depending on where it is running. This is the simplest thing that works fast. In the future, we want to have a more flexible task stealing queue, but contention destroys GPU performance, so, that's the best thing that works, for now.
2. Benchmarks aside, large scale verified programs would run much faster on Bend for a simple reason: Bend is fully explicit. It has no tactics, and it does zero compile-time search. As always: the less a computer does, the faster it runs. This is a tradeoff. In exchange, Bend code is substantially more verbose than Lean, and it is more laborious to write Bend proofs. I argue this is the right tradeoff, because AI write proofs, and AI time is cheap, while bugs take human time, which is expensive.
3. Sorry I'm not proud of the commit history
4. I don't think it is worthy publication because the core idea is simple. We just use QTT-like linear types to fully prohibit runtime closures. So, paradoxes like Russel's and Girard's are blocked. In exchange, functions like List.map are not expressive (without templates). So it is not a research breakthrough. I just made a conscious trade here, which makes Bend way closer to C or Rust, than to Haskell or Lean.
5. Will patch.
Great questions actually, and surprisingly respectful. I appreciate it a lot.
1. thanks, I'll try to take a look later at this. Most of my skepticism was rooted in a personal-hell I endured when trying to parallelize SAT-solving with GPUs...which didn't go well because its hard to share across workers effectively. Another thing to note, I'd frown upon using Claude-written works for communication between humans. If the ideas are yours then it should be feasible to write the paper. Many people will take "Claude wrote this paper" as a big sign telling them to ignore it
2. With no offense, but until it is demonstrated that this is useful for larger verified software projects I will be intensely skeptical; and, I'd advise not making claims like this until you have empirical evidence
4. Assuming this all holds air and isn't AI-bs (I'll make no claims in either direction), then yeah I'd say its valid research. To be clear with what you're claiming here, you're giving the impression that you have a GPU-accelerated proof assistant that is 2 orders of magnitude faster than Lean. If true, then that's a big and interesting contribution
Best of luck with everything. I certainly understand the frustration with how slow proof assistants can be, and I hope that we as a community can significantly speed them up
2 isn't a big claim though, I think anyone developing Lean or Agda would agree these would be much faster with zero inference, unification or search? They'd just complain the language would become unergonomic, and that's true. Bend is very verbose.
Thanks and your feedbacks are reasonable, I appreciate
After looking through things a little more, I think I may have had some misunderstandings. Would you be willing to answer a few more questions? I will also take a closer look at the papers at some point, so apologies if these are redundant
1. When I see a comparison of a new proof checker to something like Agda/Lean, I initially evaluate them as systems for formalized mathematics, but I don't think you're making claims of that nature. Would you say that you'd expect, say, the new giganto proof of Fermat's Last Theorem to be expressible in Bend and faster than the corresponding Lean proof?
2. If the answer to the last one is no, that's not expressible, then what is the class of propositions/types that you express? My initial reading was that it was the whole of affine dependent type theory
3. Is the GPU used at both runtime and compile time?
1. I do, but probably not in the current version, since I believe these proofs probably need full closure cloning to be ergonomic.
2. You can express anything actually, because you can clone data, just not functions. So, anything you could implement with datatypes (i.e., without cloned closures), you could probably also prove. But again, people use and abuse closure cloning a lot in Lean. So, how ergonomic would that be? I don't know. It is less about expressivity and more about ergonomics.
3. No, just in the runtime for now. Checking proofs on the GPU will happen when we implement Bend in itself.
Hey, I get a 404 from that link.
fixed ty
Funny seeing you here--I'm in 590 with Max and Eric. I saw Agda and guessed it was someone from the group :)
Commit history is back!
Victor Taelin has been doing interesting PLT research for 10+ years.
I suggest you read his history: https://gist.github.com/VictorTaelin/77fd5a2a8a4a07e1da6157e...
before making slop accusations. Older variant of what became Bend is 5 years old, so definitely not "vibe coded": https://github.com/HigherOrderCO/HVM1
This is a very strange comment
First, I think everything I said was respectful and rooted in the content of the Bend page rather than an assault of Victor as a person. I’m very confused by your random appeal to the author’s reputation here. He seems like a smart and cool dude, and I still have things to say in response to what’s presented here for Bend
Second, the paper is openly written by Fable 5.1, so I’m not making any unfounded accusations
To pick on a few examples:
> a random vibecoded project
> If this weren't slop...
> I'm glad you're having fun vibecoding, and I like that you're interested in this area of research/engineering
These impute both his motives ("fun") and particularly his level of seriousness ("random project" and "I like that you're interested"—imputing passivity, as opposed to "are studying" or "are researching," which would be more appropriate given the amount of time invested). They're all dismissive and patronizing.
I would actually regard this as bullying. Some feedback.
(I suspect you're an academic, either a researcher or student. I know from my own experience that bullying is endemic in many academic research environments, so if you find the negativity you're receiving "strange," I suggest finding a therapist, who may help you understand how your communication habits could be negatively affecting other people and unintentionally damaging your relationships.)
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Victor put 5+ years of research into this. You can find many of previous versions (which use different approach, do a different kind of a thing, etc.) on the github. "Bend2" in particular have been in development for 2 years.
Calling this "a random vibecoded project" is rather disrespectful, don't you think?
Regarding the paper, he states it clearly "designed by the human author". That's not at all the same as just asking Fable to write a paper. I mean the important thing is ideas, not the way they are described.
Please tell me how "I'm glad you're having fun vibecoding" is not disrespectful?
I thought that you thought Bend web site is all that is to it and wanted to point to relevant information. But if you think that "having fun vibecoding" is an appropriate thing to say to somebody who spent many years doing research, I don't know what else to say.
Again, as a "proof of research" take a look at : https://github.com/VictorTaelin/Interaction-Type-Theory that's 3 year old, pre-dates Fable, but OMG doesn't look like a paper.
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You expect an arxiv only paper to be cited? Do you even know fuck all about scientific research? Do you think someone can slap "Foundations of" in an arxiv title and we are mandated to cite it?
Yes, I'd expect a 2 year old preprint from a rising research in this utlra-niche field to likely be discussed when someone is claiming to have a sweeping solution on exactly the same research question
Maybe not necessarily so, but while looking through the paper's bibliography I get the sense that these were AI-gathered references because there seems to be gaps in the current literature on this topic