Walsh–Hadamard and Fourier below n log n: Sussman's Lean proofs
- lower bound ≈ 0.00053992by jacobalansussmangithub.com
- lower bound ≈ 0.00074745by jacobalansussmangithub.com
- lower bound ≈ 0.00087625by jacobalansussmangithub.com
- Last checked
Cite this frontier
DiscoverIA. Walsh–Hadamard and Fourier below n log n: Sussman's Lean proofs [Frontier, checked on Oct 12, 2026]. DiscoverIA registry. https://discoveria.ai/en/frontieres/walsh-hadamard-lean/
Only the lower bound is tracked. The lower bound has moved 3 times since 2026, most recently on Oct 10, 2026.
1 − z, where one fixed program computes the Walsh–Hadamard transform of length n = 2^k in O(n (log n)^z) operations (z < 1) in the exact RAM model of OpenAI's family 130, with a Lean proof accepted by the kernel; a proof gives a lower bound on the best saving 1 − z.
The WHT statement is Sussman's (about 60 lines of definitions added to OpenAI's RAM model, kept verbatim): OpenAI states only the DFT. The repository's DFT-of-every-length (and convolution) values are shown off the staircase (comparable: false), one ten-billionth below the WHT; they reuse OpenAI's statement (UniformFourier.lean) with the exponent replaced. Proofs are accepted by the Lean kernel, the official comparator and Compare.lean; no line-by-line human review (README). Asymptotic exponent savings, not running times; no claim on bit complexity or numerical stability.
Linked announcement in the registry
- Not evaluated describes the scope of the Lean formalization
Every step, as a table : Lower bound (8 points)
Best saving 1 − z proved in Lean for the WHT (start: constant of OpenAI's tensor engine).
| Date | Exact value | Nature | Authors | Source |
|---|---|---|---|---|
| Oct 10, 2026 | 8762479/10000000000 Current record | merged | jacobalansussman | github.com |
| Oct 10, 2026 | 8762478/10000000000 | merged (≠) | jacobalansussman | github.com |
| Oct 10, 2026 | 7547361/10000000000 | proposed | chafreaky | PR #2 |
| Oct 9, 2026 | 7474546/10000000000 | merged (≠) | jacobalansussman | github.com |
| Oct 9, 2026 | 7474547/10000000000 Current record | merged | jacobalansussman | github.com |
| Oct 9, 2026 | 5399225/10000000000 Current record | merged | jacobalansussman | github.com |
| Oct 6, 2026 | 2/100000000000 Current record | published | OpenAI | github.com |
| Sep 25, 2026 | 1e-13 | published (≠) | OpenAI | github.com |
(≠): value measured in another setting; shown, not counted in the bounds.
Other tracked problems (8)
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