# Harmonic Aristotle

10 Hacker News commenters recommended Harmonic Aristotle and 2 criticized it, November 2025 to November 2026. It was recommended in 4 of 13 months. It meets the Hacker Approved badge rule.

**Verdict:** Recommended for math proofs whose answers are checked in Lean, so people can trust the results. It is used to formalize theorems and proofs from papers.

## Why people recommend it

- Outputs checked in Lean (2 comments): "Aristotle's output is formally verified in Lean, so you can run it for days on a hard problem and be assured that the answer is right" ([source](https://news.ycombinator.com/item?id=46562018)) "there is no doubt that the proof is correct" ([source](https://news.ycombinator.com/item?id=46561569))
- Strong at formalizing proofs (4 comments): "I recommend trying Aristotle for yourself to see how reliably it can formalize these theorems" ([source](https://news.ycombinator.com/item?id=46561969)) "Codex formalizes much better than any tool with exception of Aristotle from Harmonic." ([source](https://news.ycombinator.com/item?id=48072297)) "recently opened a public API that got 10/12 problems on this year's Putnam exam" ([source](https://news.ycombinator.com/item?id=46296801))
- Essential to others' research (3 comments): "Aristotle ( https://arxiv.org/abs/2510.01346 ) is key here folks." ([source](https://news.ycombinator.com/item?id=46560911)) "Aristotle ( https://arxiv.org/abs/2510.01346 ) is key here folks" ([source](https://news.ycombinator.com/item?id=46560869)) "It could not be done without Aristotle" ([source](https://news.ycombinator.com/item?id=46560983))
- Impressive power people underestimate (2 comments): "people - even here, of all places - keep underestimating just how much power there is in that" ([source](https://news.ycombinator.com/item?id=46561391)) "This deserves a HN thread in its own right!" ([source](https://news.ycombinator.com/item?id=46561314))

## Alternatives hackers recommend

- [Leanstral by Mistral](https://hackerapproved.com/p/leanstral-1-5.md): 15 recommend
- [DeepSeekMath-V2](https://hackerapproved.com/p/deepseekmath-v2.md): 10 recommend

## Where to get it

- [Visit the official site](https://www.harmonic.fun/)

## Cite as

Hacker Approved, "Harmonic Aristotle", https://hackerapproved.com/p/aristotle/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).