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Algebra · Result 201

A counterexample to Kurosh’s division-ring problem

1 paper

Constructs a countable characteristic-zero division ring that is algebraic over its center and generated by two elements over that center, but has infinite dimension over it. This answers Kurosh's division-ring problem on local finiteness negatively.

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▶Introduction: the problem and why it mattersin preparation
▶The presented solutionin preparation

Papers 1

First page of A Counterexample to Kurosh’s Division-Ring Problem

A Counterexample to Kurosh’s Division-Ring Problem

OpenAI · September 23, 2026

We construct a countable division ring of characteristic zero that is algebraic over its center, generated by two elements as an algebra over that center, and infinite-dimensional over it. This gives a negative answer to the Kurosh problem for division rings.

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Cite
@misc{OAI:A-Counterexample-to-Kuroshs-Division-Ring-Problem-September-23-2026,
  author = {{OpenAI}},
  title = {{A Counterexample to Kurosh's Division-Ring Problem}},
  howpublished = {OpenAI Math Release preprint
                  \href{https://github.com/openai/math/blob/main/preprints/A-Counterexample-to-Kuroshs-Division-Ring-Problem-September-23-2026/paper.pdf}{OAI:A-Counterexample-to-Kuroshs-Division-Ring-Problem-September-23-2026}},
  year = {2026}
}

Formal verification

No Lean formalization is listed for this result yet. The repository notes that unformalized results could have issues.