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Number theory

How closely can a fraction approximate pi?

OpenAI research collection · 1 manuscript · Source checked 2026-10-19

The idea in plain language

Fractions can get very close to pi, but how close depends on their denominator. This manuscript claims to pin down the best possible long-run rate of approximation, settling the irrationality exponent of pi at two.

Why it matters

A familiar constant becomes a demanding test of new reasoning. The result concerns approximation limits; it does not make pi rational or change its digits.

Read the technical source claim

Proves that the irrationality exponent of π is exactly 2: for every ε > 0 and all sufficiently large denominators q, every rational p/q satisfies |π-p/q|≥ q^{-2-ε}. This also proves convergence of the Flint–Hills series \sum_{n\ge1}1/(n^3sin^2 n), with angles in radians.

Read the manuscripts

Short excerpts below come from OpenAI's abstracts. The full abstract and original PDF preserve the paper's precise scope.

MANUSCRIPT 01

The irrationality exponent of pi is 2

We prove the conjecture that the irrationality exponent of π is 2. As a consequence, the classical Flint–Hills series \sum_{n\ge1}1/(n^3sin^2 n) converges, with angles in radians.

This exact PDF is not listed in the imported formalization catalogue. Family scope notes may contain further information.

One signal in the wider AGI picture

New mathematical reasoning could help AI tackle harder scientific and computational problems. How reliably these skills transfer beyond mathematics will determine how much they contribute to general intelligence.

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