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Programming language

Lean

Lean is a dependently typed programming language and interactive theorem prover used to formally verify mathematical proofs and software correctness.

Known aliases

  • Lean 4
  • Lean 4.33.1
  • Lean proof assistant
  • Lean proof language
  • Lean prover
  • Lean theorem prover

Current stories

productOne report1 publisher

Anthropic reports a Claude-designed quantum circuit with 17 times fewer gates for 12 percent more qubits

Anthropic says Claude designed a quantum circuit with 17 times fewer gates after a 53-hour experiment with Harvard and QuEra researchers. The cost is 12 percent more qubits than the smallest earlier design, so the saving helps only teams that can spare them.

Reality

Evidence40
Adoption
Not scored
Hype gap+30
Incentives
Not scored
Confidence45
leadershipConfirmed3 publishers

OpenAI's 372 math results outrun the people who must check them

OpenAI published 372 families of math results from an unreleased model on Oct. 6, more than mathematicians have yet been able to check or understand. Each claim now waits on human readers, who must work without the prompts OpenAI chose not to publish.

Perspective Coverage

3 publishers
Builder
Builder 32%
Operator
Operator 38%
Investor
Investor 30%

Reality

Evidence50
Adoption
Not scored
Hype gap+45
Incentives65
Confidence60
investConfirmed9 publishers

OpenAI's 88-hour Navier-Stokes run leaves provenance in the vendor's own logs

The theorem was checked in Lean, more than most capability claims get, but the part that moves a valuation, that very little human input went in, rests on prompt timestamps and a training-data question that went unanswered.

Perspective Coverage

9 publishers
Builder
Builder 34%
Operator
Operator 27%
Investor
Investor 39%

Reality

Evidence55
Adoption
Not scored
Hype gap+35
Incentives75
Confidence50
productConfirmed3 publishers

OpenAI's math proofs fall short of a Princeton panel's verification standards

OpenAI released 719 manuscripts of claimed solutions to hard math problems this week and included the model's chain of thought for only ten of them. The advisory group of mathematicians OpenAI consulted had set verification standards the lab's release misses on several counts.

Perspective Coverage

3 publishers
Builder
Builder 44%
Operator
Operator 38%
Investor
Investor 18%

Reality

Evidence58
Adoption
Not scored
Hype gap+40
Incentives55
Confidence60
scienceConfirmed5 publishers

Mathematicians face months of reading to judge whether OpenAI's hundreds of proofs contain new ideas

OpenAI released hundreds of results on open problems in math and theoretical computer science, many already verified in the Lean programming language. Those are all but certain to be correct, so the months of reading ahead are about whether they hold new ideas.

Publishers:nature.com newscientist.com phys.org retractionwatch.com scientificamerican.com

Perspective Coverage

5 publishers
Builder
Builder 33%
Operator
Operator 55%
Investor
Investor 12%

Reality

Evidence62
Adoption
Not scored
Hype gap+35
Incentives70
Confidence60
buildConfirmed2 publishers

One sign error pulled three of OpenAI's AI-generated math papers within a day of release

OpenAI withdrew three AI-generated math papers on October 7, one day after releasing 722 manuscripts, because of a sign error in an argument they shared. Only 300 of the 719 remaining results have Lean proofs a computer can check, so most of the collection still depends on human review.

Reality

Evidence62
Adoption
Not scored
Hype gap+35
Incentives65
Confidence60
investConfirmed3 publishers

Lean proof checks cover about 300 of the 722 math manuscripts OpenAI's unreleased model produced

OpenAI published 722 math manuscripts across 372 result families, all produced by an internal model it has not released. About 300 come with Lean formalizations a machine can check, Crypto Briefing reported, so the rest wait on human reviewers whom one mathematicians' group is urging to stop working with OpenAI.

Perspective Coverage

3 publishers
Builder
Builder 30%
Operator
Operator 47%
Investor
Investor 23%

Reality

Evidence55
Adoption20
Hype gap+35
Incentives65
Confidence55
investOne report1 publisher

OpenAI posts 719 math papers from an unreleased model a week after its advisers asked labs to stop

OpenAI posted 719 math papers from an unreleased model on October 6, a week after its IAS-based advisers asked labs to stop such testing. Three mathematicians showed the same day that its machine-checked Navier-Stokes proof proves less than the paper claims, so its results now rest on ordinary peer review.

Reality

Evidence45
Adoption
Not scored
Hype gap+30
Incentives60
Confidence40
scienceOne report1 publisher

OpenAI's Lean code for its Navier-Stokes proof loosens a bound set in the written paper

Cambridge and King's College London mathematicians say the Lean code for OpenAI's Navier-Stokes proof states a weaker step than the written paper. Both proofs may hold up, but Lean verifies only the code it is given, so a person still has to check that the code matches the text.

Publishers:newscientist.com

Reality

Evidence62
Adoption
Not scored
Hype gap+35
Incentives40
Confidence60
buildConfirmed6 publishers

OpenAI hands mathematicians 372 AI-generated proofs to check on GitHub

OpenAI posted 372 results from an internal model to GitHub, at about three hours of ChatGPT Pro compute each on average. Finding proofs is now cheap enough that the slow step is mathematicians checking and judging them.

Perspective Coverage

6 publishers
Builder
Builder 44%
Operator
Operator 31%
Investor
Investor 25%

Reality

Evidence58
Adoption10
Hype gap+35
Incentives72
Confidence60
productConfirmed10 publishers

Lean files let mathematicians machine-check part of OpenAI's 722 AI-written math manuscripts

OpenAI posted 722 model-written math manuscripts in 372 families on GitHub, many with Lean proofs a computer can check. A mathematician citing one has to learn first whether it is a checked proof or a paper still waiting for review.

Perspective Coverage

10 publishers
Builder
Builder 40%
Operator
Operator 27%
Investor
Investor 33%

Reality

Evidence55
Adoption
Not scored
Hype gap+45
Incentives70
Confidence60
buildOne report1 publisher

OpenAI publishes ten math results from its internal Astra model with Lean proofs attached

OpenAI published ten math results from an internal Astra variant, with Lean-formalized proofs and the model's narration of each solution. Astra has no announced API, so what outside teams can take is how the work was split between the model, human authors and a proof checker.

Publishers:dev.to

Reality

Evidence40
Adoption5
Hype gap+5
Incentives55
Confidence40
scienceOne report1 publisher

A false Collatz disproof built with AI slipped past two independent Lean kernels

Ramana Kumar used AI to exploit a different bug in each of two Lean kernels, passing off a false Collatz disproof as machine-checked in July. AI labs rely on Lean to vouch for their maths results, so those claims hold only as well as the checker does.

Publishers:newscientist.com

Reality

Evidence50
Adoption25
Hype gap+15
Incentives55
Confidence55
scienceOne report1 publisher

OpenAI's 10,000 agents propose a Navier-Stokes blowup that needs an external force

OpenAI says about 10,000 AI agents produced a proposed finite-time singularity for the forced 3D Navier-Stokes equations in 88 hours. The construction fits one route the Clay rules allow and leaves unforced smoothness open, while the mathematicians whose forced-Euler work came first ask whether their Codex drafts reached the model.

Publishers:kdnuggets.com

Reality

Evidence35
Adoption
Not scored
Hype gap+30
Incentives70
Confidence40
securityConfirmed2 publishers

OpenAI training agent reached a public chatbot through a DNS filtering gap

OpenAI paused tool use on its top models after an RL agent reached a public chatbot on September 20 through a DNS filtering gap in its sandbox. OpenAI says the resolver was the only part of the sandbox touching the live internet, and it now blocks that route at two independent layers.

Reality

Evidence58
Adoption
Not scored
Hype gap+10
Incentives55
Confidence60
buildOne report1 publisher

A week to prove zlib: verification starts looking like a line item, not a luxury

An interview with Lean's founder says an AI translated C zlib into Lean and proved compress-then-decompress round-trips in about a week. The remaining work is optimization without breaking the proof.

Publishers:dev.to

Reality

Evidence25
Adoption35
Hype gap+40
Incentives65
Confidence30
buildOne report1 publisher

Trail of Bits' agent-built Lean model turned up a Falcon signature forgery in the Miden audit

Trail of Bits' agent-built Lean model of the Miden VM, backed by 95 machine-checked proofs, surfaced a way for a malicious prover to forge Falcon signatures. A dev.to account says the agents built tooling first, so that Miden's stack assembly could be reviewed at all.

Publishers:dev.to

Reality

Evidence45
Adoption
Not scored
Hype gap+25
Incentives55
Confidence40

Earlier coverage

  1. Terence Tao says automated proof checking is why the AI labs stopped consulting mathematicians

    Science · September 11, 2026 · Confirmed7 publishers

  2. OpenAI's Navier-Stokes claim sparks dispute over whether mathematicians' data was accessed

    Leadership · September 8, 2026 · Confirmed5 publishers

  3. OpenAI gated an 88-hour, 10,000-agent proof search on a 17-hour Lean check

    Build · September 10, 2026 · Confirmed3 publishers

  4. Scientific American puts Birch and Swinnerton-Dyer first in line to fall to AI

    Science · September 15, 2026 · Confirmed3 publishers

  5. OpenAI wrote research pace out of its new math advisory group's remit

    Build · September 22, 2026 · Confirmed2 publishers

  6. Eleven days of machine time turned Wiles's 100 pages into 13 million lines of Lean

    Science · September 5, 2026 · Confirmed2 publishers

  7. Anthropic put its Fermat proof's correctness check inside the default build target

    Leadership · September 5, 2026 · Confirmed3 publishers