Plectis Atlas
Search

↑ and ↓ move, Enter opens, Esc closes.

Exact Fourier transforms below \(n\log n\)

OpenAI groups related papers into a “family”. OpenAI’s catalogue describes this one:

Gives a deterministic length-n discrete Fourier transform algorithm using \(O(n(\log n)^{1-\delta})\) operations for every n, with explicit \(\delta=10^{-13}\). The model uses exact complex arithmetic, unrestricted coefficients and a supplied root of unity, and counts scalar preparation and logarithmic-word indexing. (OpenAI’s Lean note)

Lean is a language for mathematical statements and proofs that a computer can verify. The assessments below ask whether those statements express the result OpenAI describes here.

Both independent assessments find that the Lean statements express or imply the whole result described above. Read the assessments

What the papers state

Theorem 1.1

In An explicit power saving for the exact discrete Fourier transform, 25 September 2026

The paper’s main theorem is shown as a possible match to OpenAI’s description. No review confirming the selection is recorded.

There is a single deterministic algorithm which, for every positive integer n and every x\in\C^n, computes F_nx exactly. In the model above, including scalar preparation, schedule construction, and index work, its running time is

O\!\left(n(\log n)^\theta(\log\log n)^{4-\theta}\right)

as n\to\infty. It suffices to supply the specified root \zeta_{D_*} for an explicitly computable integer D_*<1024n^3.

No Lean statement in the release is paired with this theorem.

Corollary 1.3 (Exact convolution and polynomial multiplication)

In An explicit power saving for the exact discrete Fourier transform, 25 September 2026

Possible match to OpenAI’s description, selected because it shares the most wording. No review confirming the selection is recorded.

There is a single deterministic algorithm which, for every positive integer n and every a,b\in\C^n, computes the linear convolution

\begin{gathered}c_k=\sum_{\substack{0\le r,s<n\\r+s=k}}a_rb_s, \qquad 0\le k\le 2n-2.\end{gathered}

Equivalently, it multiplies two complex polynomials of degree less than n. In the exact complex field-operation, specified-root, and address cost model above, with general field multiplication permitted for the pointwise products, the total running time, including scalar preparation, schedule construction, padding, and index work, is

O\!\left(n(\log n)^\theta(\log\log n)^{4-\theta}\right) \qquad(n\to\infty),

and hence is eventually O(n(\log n)^{1-10^{-13}}). This is a bilinear arithmetic algorithm, not an input-linear circuit: its pointwise products multiply a value linear in a by a value linear in b.

The release does not say which paper theorem its catalogue describes. Both statements above are shown whole: the paper’s main theorem first, then the statement that shares the most wording with the description. The atlas has not reviewed either choice.

Two more possible matches

  • Corollary 1.2 in An explicit power saving for the exact discrete Fourier transform, 25 September 2026.
  • Theorem 1.1 in Finite tensor savings and exact Fourier circuits, 25 September 2026.
Reported proof verification
Two Lean statements in the release; independent groups report that Comparator accepted runs for all these files at the version shown here.

Papers

Each paper opens as a reading page in the browser, with the PDF beside it. The statements each paper opens with are on its reading page.

An explicit power saving for the exact discrete Fourier transform

25 September 2026, current edition.

Read it herePDF

We give a deterministic algorithm that computes the discrete Fourier transform at every length n in \(O(n(\log n)^{1-10^{-13}})\) operations. The model uses exact complex arithmetic, unrestricted coefficients, specified Fourier roots, and unit-cost logarithmic-size indexing; scalar preparation and array organization are included.

Finite tensor savings and exact Fourier circuits

25 September 2026, current edition.

Read it herePDF

We construct exact nonuniform Fourier circuits of size \(o(n\log n)\) along an unbounded sequence of lengths, counting every addition, subtraction, and scalar multiplication. This refutes the \(\Omega(n\log n)\) lower bound in the unrestricted complex linear-circuit model. The construction uses a finite tensor saving: a tensor power of some invertible nonmonomial complex matrix can be computed with fewer matrix calls than the standard tensor-axis algorithm on the same coordinates, when invertible monomial maps are allowed freely between calls.

Two Lean statements in this family

Choose one to see it beside the paper theorem it is paired with.

For a configured theorem, the Comparator program tests whether OpenAI’s separate proof proves the exact Lean statement using only the allowed axioms. Some statement files instead configure definitions for comparison by name and type. Acceptance does not establish that a formal statement means the same thing as the paper’s theorem.

ExactFourier

The paper states

Proposition 3.4 (Transfer of a finite win)

In Finite tensor savings and exact Fourier circuits, 25 September 2026

If a finite win exists, there are integers n_m\to\infty and exact linear circuits for F_{n_m} whose scalar gate counts satisfy

L(n_m)=o(n_m\log_2n_m).

In particular the conclusion is in the model charging additions, subtractions, and multiplication by every prechosen complex scalar.

The words they share: charging, gate, circuits, complex, scalar, integers, subtractions, additions, multiplication, log.

Possible Lean counterpart

Selected from shared wording. No review of whether the statements mean the same thing is recorded.

Subsequential savings for exact Fourier circuits

ExactFourier.lean, the release lists it as a main result.

def MainStatement : Prop :=  ∀ c : ℝ, 0 < c → ∀ N₀ : ℕ, 2 ≤ N₀ → ∃ n : ℕ, N₀ ≤ n ∧    ∃ C : Circuit n, C.Computes (fourierMatrix n) ∧      (C.size : ℝ) < c * (n : ℝ) * Real.logb 2 (n : ℝ)theorem main_theorem : MainStatement := by  sorry

This file states the theorem with sorry, a placeholder, in place of its proof. OpenAI supplies a separate proof file. Comparator tests whether that proof proves the statement here.

three independent groups report that Comparator accepted runs for this Lean statement file: cert-machine; MathVet; Neal McBurnett, openai-math-lean-tooling. Who ran the proof-verification program

  • cert-machine records it as “CERTIFIED”.
  • MathVet records it as “comparator-sandboxed-pass”.
  • Neal McBurnett, openai-math-lean-tooling records it as “accepted”.

Read the complete Lean statement

UniformFourier

The paper states

Corollary 1.3 (Exact convolution and polynomial multiplication)

In An explicit power saving for the exact discrete Fourier transform, 25 September 2026

There is a single deterministic algorithm which, for every positive integer n and every a,b\in\C^n, computes the linear convolution

\begin{gathered}c_k=\sum_{\substack{0\le r,s<n\\r+s=k}}a_rb_s, \qquad 0\le k\le 2n-2.\end{gathered}

Equivalently, it multiplies two complex polynomials of degree less than n. In the exact complex field-operation, specified-root, and address cost model above, with general field multiplication permitted for the pointwise products, the total running time, including scalar preparation, schedule construction, padding, and index work, is

O\!\left(n(\log n)^\theta(\log\log n)^{4-\theta}\right) \qquad(n\to\infty),

and hence is eventually O(n(\log n)^{1-10^{-13}}). This is a bilinear arithmetic algorithm, not an input-linear circuit: its pointwise products multiply a value linear in a by a value linear in b.

The words they share: arithmetic, bilinear, circuit, complex, computes, construction, convolution, cost, deterministic, exact, including, input, integer, model, multiplication, positive, preparation, root, scalar, total, work.

Possible Lean counterpart

Selected from shared wording. No review of whether the statements mean the same thing is recorded.

Uniform exact DFT and convolution with a power saving

UniformFourier.lean, the release lists it as a main result.

def DFTGoal : Prop := ∃ order solve W, DFTProgram order solve W ∧ TimeBounds Wtheorem transform_main : DFTGoal := by  sorry

This file states the theorem with sorry, a placeholder, in place of its proof. OpenAI supplies a separate proof file. Comparator tests whether that proof proves the statement here.

The file states one more theorem: convolution_main.

two independent groups report that Comparator accepted runs for this Lean statement file: cert-machine; MathVet. Who ran the proof-verification program

  • cert-machine records it as “CERTIFIED”.
  • MathVet records it as “comparator-sandboxed-pass”.

Read the complete Lean statement

Independent comparisons and proof-verification reports

Does the Lean express the advertised result?

MathVet and cert-machine agree on how much of the advertised result the Lean statements express.

MathVet and Carlos Toledo’s cert-machine independently assessed whether this family’s Lean statements express the whole result OpenAI describes in its catalogue. These are assessments of the family as a whole, not of each paper theorem separately.

MathVet finds that the Lean statements express or imply the whole advertised result (their term: “full”).

Their note: UniformFourier.transform_main (DFTGoal) states that one fixed pair of closed RAM programs (order, solve) outputs dft n x exactly for every n > 0 and every x, with total work including root-order selection (d.work) and scalar preparation at most W n, where W =O n(log n)^(1−10^-13) (also the paper’s θ-bound and o(n log n)); unfolding DFTGoal, DFTProgram and TimeBounds is the only step, and convolution_main likewise states Corollary 1.3. ExactFourier is the separate subsequential circuit result (for each c and N₀ some n ≥ N₀ has an exact circuit with fewer than c n log₂ n gates), which is the other paper’s theorem and not the headline claim.

Definitions the group asks readers to compare with the paper: UniformFourier RAM model (Tape, Bill, Atom, Code, Code.run, Prog, run): bespoke typed point-free RAM with unit-cost exact complex field operations and unit-cost word operations; the meaning of ‘O(...)’ rests entirely on its cost semantics. I found no undercharging: every Code node and Atom pays at least 1, tab/sow pay 1+len, loops and bounded descents pay per iteration/level, and arrays are never copied for free; UniformFourier.DFTProgram / ConvProgram: the program itself selects the root order d = run order n (0 < d < 1024 n³, its work counted) and then receives root d := ExactFourier.zeta d for free; the target is dft n with ζ_n, and every scalar the program can form lies in ℚ(ζ_d), so d must give ζ_n ∈ ℚ(ζ_d) (n | d, or d odd and n | 2d); matches the paper’s ‘specified root ζ_{D_*}, D_* < 1024 n³’; UniformFourier Atom set: the only complex constants are 0 (cz) and 1 (cone); every other scalar must be prepared from the supplied root by counted add/sub/scale/inv on scalar registers; data registers (Paint.left/right/both) cannot become scalars or integers, and ifz tests only integers, so control flow is data-independent; 'cross’ (data × data) exists only when allow = true (convolution), and only left × right ↦ both; UniformFourier Bill.valid (a Prop): the side condition that every inv has a nonzero argument on the executed path; DFTProgram and ConvProgram require d.valid and result.valid, so division by zero is excluded rather than tested; UniformFourier cap := (n+2)^cBound with ∃ cBound: forces work, root order and every produced integer (peak) to be polynomial in n, i.e. O(log n)-bit words; this is the ‘logarithmic-word indexing’ of the summary; UniformFourier TimeBounds: W =O paperTime ∧ W =O decimalTime ∧ W =o nlogn with natural logs; asymptotic only (finitely many n are constrained only by correctness and cap); paperTime uses the paper’s constants m = 10^6, W_* = 2^71, Δ = 6871402692000000 and θ = log(m − Δ/W_*)/log m; decimalTime n = n (log n)^(1 − 10^-13); UniformFourier dft / conv: dft n x j = Σ_k ζ_n^(jk) x_k with ζ_n = exp(+2πi/n) (unnormalized, same sign convention as the paper’s F_n); conv is the full linear convolution on Fin (2n−1); ExactFourier Gate / Program / Circuit: linear scalar DAG with n inputs, an extra constant 0, free reuse and fan-out, outputs naming any available value (permutations free), and scale (c : ℂ) with arbitrary complex c at cost one; coefficient generation is uncharged (nonuniform); standard for the paper’s model; ExactFourier MainStatement: subsequential (∃ n ≥ N₀ for each c and N₀), not an all-length bound; this is the intended statement of the finite-tensor paper’s thm:main

“full”, in their words: The challenge statements imply the headline claim after unpacking definitions or one routine step.

Their method: An independent, model-assisted, pre-referee reading of each family’s challenge statements against its headline claim under a published rubric (PROTOCOL.md), with its own Comparator runs per challenge.

cert-machine finds that the Lean statements express or imply the whole advertised result (their term: “MATCHES”).

“MATCHES”, in their words: The challenge statements state the headline as OpenAI wrote it.

Their method: Every Comparator challenge re-run on Linux with nanoda switched on, decided by a preregistered rule.

OpenAI’s own note on what its Lean covers

The formalized result gives exact discrete Fourier transforms with arbitrarily small normalized circuit cost along an unbounded sequence of lengths. For every $c>0$ and every cutoff $N_0\ge2$, some $n\ge N_0$ has a circuit computing the unnormalized DFT with fewer than $cn\log_2 n$ gates. Addition, subtraction, and multiplication by a predetermined complex scalar each cost one gate; diagonal scalings are charged. The result is subsequential, with no all-length, bounded-coefficient, conditioning, or bit-complexity claim.

A separate uniform formalization gives fixed deterministic programs for every positive length $n$, computing the canonical discrete Fourier transform and the full convolution of two length-$n$ complex vectors exactly. Their work is $O(n(\log n)^{1-10^{-13}})=o(n\log n)$, including root-order selection and scalar preparation. The chosen root of unity is supplied; the model permits exact complex arithmetic and unrestricted coefficients, while integer values and indices remain polynomially bounded in $n$. The synthesis appendix’s extraction, search, and printer uniformization is outside these selected statements.

AI-drafted comparisons, with no recorded human review

  • Subsequential savings for exact Fourier circuits ExactFourier

    Unreviewed AI draft: states a paper’s theorem as the paper does. States the main theorem: along an unbounded sequence of lengths, exact DFT circuits with fewer than cn log₂ n gates for every c > 0.

  • Uniform exact DFT and convolution with a power saving UniformFourier

    Unreviewed AI draft: states a paper’s theorem as the paper does. States the power-saving paper’s main theorem with its corollaries: one fixed program computing the DFT at every length, and exact convolution, in O(n(log n)^{1−10^{-13}}) operations.

Who ran the proof-verification program?

These groups report running Comparator with the release’s Lean statement files. For a configured theorem, it verifies OpenAI’s separate proof against the exact statement; some files instead configure definitions for comparison by name and type. Each row is the named group’s report. Atlas has not repeated the runs.

These reports do not list the software versions, proof-verification programs, axioms, time or memory in separate fields. Any such details in a report’s prose are reproduced below.

Subsequential savings for exact Fourier circuits ExactFourier

Three reports, all at the release’s recorded version.

Reported byTheir wordTheir accountDateOriginal report
cert-machine“CERTIFIED”Re-run through Comparator with the independent nanoda kernel switched on: Lean’s kernel and nanoda both accept OpenAI’s solution.10 October 2026Original report
MathVet“comparator-sandboxed-pass”Re-run through Comparator in a sandboxed virtual machine: accepted.8 October 2026Original report
Neal McBurnett, openai-math-lean-tooling“accepted”Re-run through Comparator with Lean’s kernel: accepted (the check took 195 s; peak memory 6.6 GiB).11 October 2026Original report

Uniform exact DFT and convolution with a power saving UniformFourier

Two reports, all at the release’s recorded version.

Reported byTheir wordTheir accountDateOriginal report
cert-machine“CERTIFIED”Re-run through Comparator with the independent nanoda kernel switched on: Lean’s kernel and nanoda both accept OpenAI’s solution.10 October 2026Original report
MathVet“comparator-sandboxed-pass”Re-run through Comparator in a sandboxed virtual machine: accepted.10 October 2026Original report

Other proofs and exact calculations

These reports examine claims in the papers using exact calculations for finite claims, independently of the release’s Lean proofs. Read each report for the exact claim it covers.

  • Lemma A.1 of An explicit power saving for the exact discrete Fourier transform, 25 September 2026

    Reported by
    cert-machine
    Method
    Exact computation
    Their verdict
    “NEEDS DATA” Cannot be decided from the release: the specific object the argument relies on is not published.
    Original report
    Their report

Explanations by others

Explanations of this family written elsewhere, by the people named. Each is their own reading of the mathematics.

  • Scientific American (byline not recorded), The most exciting claims from OpenAI’s heap of new proofs, 8 October 2026. Source

    The article explains that paper 130 lowers the log n factor in the n log n Fourier transform to a power just below 1, a tiny improvement that nonetheless breaks a barrier of the 1960s.

  • seaworld008, seaworld008/openai-math-top30: thirty selected families explained in Chinese, 7 October 2026. Source

    Chinese-language explainer for general readers, with a beginner’s section, a specialist section, background on why the problem was hard and a diagram; it ends by saying it paraphrases OpenAI’s summary and does not represent consensus.

What these papers cite in the release, and what cites them

These links come from the papers’ bibliographies. A citation records that one paper cites another; how each cited result is used has not been examined here.

Within this family

Papers elsewhere in the release that this family’s papers cite

Papers elsewhere in the release that cite this family’s papers

No paper elsewhere in the release cites this family’s papers.

Follow-up work by others

  • danadran01, exact-dft-power-saving, 9 October 2026. Source

    A repository claims an exact discrete Fourier transform saving of about 3.2 millionths in the exponent against the manuscript’s one ten-trillionth, verified in Lean; it is a claim by the owner and not independently checked.

  • Jacob Sussman, jacobalansussman/wht-power-saving-lean: Lean proofs for the DFT and Walsh-Hadamard transform saving, 9 October 2026. Source

    Lean-checked saving of 8.76e-4 for the all-length DFT (the five-stage network).

  • Ryan Shea, shea256/fourier-transform-below-nlogn, 9 October 2026. Source

    The project rebuilt the Lean proof of Sussman and Boukhalfa’s five-stage theorem: the release’s UniformFourier statement with the saving raised from 10^-13 to 0.000754736. Its 91 imported OpenAI files are byte-identical at fd4aeeb2. The comparison used Sussman’s Compare.lean rather than OpenAI’s Comparator, and human review is pending.

  • Ryan Shea, shea256/fourier-transform-below-nlogn, 8 October 2026. Source

    A conditional exponent saving for the exact discrete Fourier transform built on the community integer multiplication network, published as an unreviewed research draft with verifiers.

  • chris1234555, chris1234555/ncc-certificate: Lean certificate that the Li-Li network coding conjecture is false, 7 October 2026. Source

    Lean refutation of a consequence of the network coding conjecture using the family 130 DFT circuits.

References outside the release

Each paper’s outside references are listed with it on its reading page, where each citation is placed. Every outside work cited in the release: References outside the release

Explain a result, compare statements or propose a correction

Atlas has no contributed explanation for this family yet. You can offer one with a GitHub account. You receive named credit and disclose any AI assistance.

Each button opens a GitHub form with this page and its source version filled in. Opening the form does not reserve the work.

Offer to write an explanationCompare one Lean statement with its paper: ExactFourier, UniformFourierSuggest a source attributionSuggest a change

What people have said

Commentary on this family by others, dated and credited. It is commentary, not a finding.

  • An unsigned public tier list, the OpenAI Math Tier List, classes it as a algorithm and rates its significance, if it holds up, as “Career-defining publication”. The page says that nothing on it is verified.

    Author not stated. Source

  • Scientific American (byline not recorded), The most exciting claims from OpenAI’s heap of new proofs, 8 October 2026. Source

    Paper 130 reduces the log factor in the fast Fourier transform to a power just under 1, a tiny improvement that breaks a long-standing barrier.

Questions awaiting review

Each item identifies a statement, definition or report that needs further review. Its link opens a GitHub form with the source version already recorded.

Read the Lean statement against the paper

  • An AI agent drafted an assessment of which part of the paper this Lean statement expresses. No named human review is recorded. Open the form
  • An AI agent drafted an assessment of which part of the paper this Lean statement expresses. No named human review is recorded. Open the form

Identify the theorem the catalogue describes

  • Family 130 The theorem shown was selected from shared wording with OpenAI’s description. Atlas records no review confirming that it is the theorem the description means. Open the form

Address a question raised in an independent assessment

Compare the proposed paper and Lean matches

  • Family 130 Atlas records no review of whether each linked Lean statement and paper theorem mean the same thing. Open the form

Investigate a calculation that did not decide the claim

  • Family 130 An independent calculation did not decide the claim, or needs data absent from its source. Open the form