OpenAI's Unreleased Model "Astra" Solves 10 Unsolved Mathematical Problems for $2000
On August 1st, OpenAI made an unusual announcement. Their next flagship model, "Astra," which is not yet publicly available, solved 10 problems in the fields of mathematics and theoretical computer science that had remained unsolved for over 10 years, and released all of them with "machine-verifiable certificates." For engineers, what makes this news interesting is not the results themselves, but "why this time it can be believed."
The Deep-Seated Distrust of "Another AI Solves Math Problem"
Many engineers must have felt a sense of déjà vu upon hearing this news. In fact, in October 2025, an OpenAI executive at the time announced that "GPT-5 had solved 10 unsolved problems of the Erdős conjecture." However, this announcement crumbled within days. Mathematician Thomas Bloom's verification revealed that the model had merely "searched" for solutions from existing literature and had not constructed its own proofs. What makes Astra's announcement different is that Bloom himself has described it as "important news." The mechanism that convinced him and the entire mathematics community is the core of this announcement.
Providing proofs in a "verifiable" format, not just a "readable" one
The key technical point is that all ten proofs were formalized using Lean 4, a "theorem proving assistance system" (a tool that allows mathematical proofs to be written in a format that a computer can verify line by line, like a program).
Normally, mathematical proofs generated by AI can only be judged by human mathematicians as "likely correct." However, with Lean-format proofs, readers can mechanically verify whether the proof is truly correct simply by running the code on their own laptops. The repository released by OpenAI reports zero occurrences of the reserved word "sorry," which indicates incomplete parts of the proof—meaning that all logical steps are complete and without omissions.
This represents a significant practical shift from "believing" in AI output to "verifying" it.
The Highlight: A Group Theory Problem Unsolved for 27 Years
The 10 results span a wide range of fields, including group theory, von Neumann algebras, higher-dimensional geometry, quantum computation, lattice cryptography, and extreme value combinatorial theory. The highlight is the first concrete example of a group construction called a "non-Sophic group."
This was a central unsolved problem in group theory, which no one had been able to prove or disprove for 27 years since mathematician Mikhail Gromov proposed the concept of "Sophicity" in 1999. This problem has now been finally resolved.
The Significance of a Computational Cost of Only $2000
According to OpenAI's research leader, Sebastian Bubek, the computational cost to derive all 10 solutions was approximately $2000 in terms of the company's API fees. This is a symbolic figure. A problem that has baffled human intellect for decades has been solved for the cost of a few hundred cups of coffee.
However, there are points to keep in mind before blindly accepting this figure. This is merely the "cost of the tokens used to derive the solution, based on their list price," and does not include the enormous research and development costs invested in training the model.
Mixed Welcome and Cautious Expectations from the Mathematical Community
This result is not simply being consumed as self-proclaimed by AI companies. In June 2026, the "Leiden Manifesto," a document endorsed by the International Mathematical Union and signed by prominent mathematicians such as Terence Tao, Peter Scholz, and Scott Aaronson, was published. This manifesto lists five risks in the relationship between AI and mathematics: low reliability of results, lack of sources, reliance on closed commercial systems, exaggerated claims, and loss of scientific independence.
Astra's announcement is designed to directly address at least three of these five risks. The proof is verifiable in Lean format, and a 249-page technical document and a 62-page explanatory document detailing how the model constructed its reasoning have been released. The stance isn't "just show us the results and believe it," but rather "we'll give you the verification process, so feel free to question it."
What Engineers Should Consider
The essence of this news isn't that "AI can now solve math problems." It's that "a system is beginning to take shape that allows third parties to independently and mechanically verify the results produced by AI."
When integrating the output of generative AI into practical work, many engineers face the hurdle of "how to verify whether this output is truly correct." While this case is a success in the highly verifiable field of mathematics, the idea of "how to provide verifiable backing for AI output" is likely to be applied to more familiar development environments, such as code generation and design document reviews.
OpenAI has also announced that it will provide 100,000 academic researchers with free access to its frontier models until 2027. While this could be seen as a move to lock research infrastructure into its own platform, if the culture of "verifiable proof" becomes the standard way in which AI and mathematical research interact, then this is a welcome direction in itself.