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<title>Coder Legion - Recent posts tagged numerical-verification</title>
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<title>Making Equation (2.2) of the OpenAI Erdős Result Executable</title>
<link>https://coderlegion.com/18955/making-equation-2-2-of-the-openai-erdos-result-executable</link>
<description>&lt;h3 id=&quot;why-a-proved-theorem-still-needs-reproducible-claim-custody&quot;&gt;Why a proved theorem still needs reproducible claim custody&lt;/h3&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=2108443327152872531&quot; alt=&quot;open ai&quot;&gt;&lt;/p&gt;
&lt;p&gt;On May 20, 2026, &lt;a rel=&quot;nofollow&quot; href=&quot;http://%20https://openai.com/index/model-disproves-discrete-geometry-conjecture/&quot;&gt;OpenAI announced&lt;/a&gt; that an internal reasoning model had produced a counterexample to the Erdős planar unit-distance conjecture.&lt;/p&gt;
&lt;blockquote&gt;&lt;p&gt;The problem is easy to state: given $n$ points in the plane, how many pairs of points can be exactly distance $1$ apart?&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;For nearly eighty years, the prevailing expectation was that square-grid-type constructions were essentially optimal up to a slowly growing exponent. OpenAI’s announcement changed that. Its internal reasoning model produced an infinite family of examples giving a polynomial improvement, and the proof was checked and written up in mathematical form by external mathematicians.&lt;/p&gt;
&lt;p&gt;In this article, “the remarks paper” refers to the companion PDF by Alon, Bloom, Gowers, Litt, Sawin, Shankar, Tsimerman, Wang, and Matchett Wood, linked from OpenAI’s announcement.&lt;/p&gt;
&lt;p&gt;The proof-level result belongs to those authors and the source papers.&lt;/p&gt;
&lt;p&gt;My focus here is narrower: equation (2.2) in that remarks paper, and whether its explicit numerical value can be reproduced as executable code.&lt;/p&gt;
&lt;p&gt;This is not about proving the theorem again. It is about what happens after a theorem contains a fragile numerical claim.&lt;/p&gt;
&lt;hr&gt;
&lt;h3 id=&quot;the-proof-is-not-the-artifact&quot;&gt;The proof is not the artifact&lt;/h3&gt;
&lt;p&gt;A mathematical proof and a software artifact do different jobs.&lt;/p&gt;
&lt;p&gt;The proof establishes the theorem. It gives the definitions, the argument, the dependencies, and the mathematical reason why the result holds.&lt;/p&gt;
&lt;p&gt;A software artifact should not pretend to replace that.&lt;/p&gt;
&lt;p&gt;But some claims inside a mathematical paper have a finite, numerical, or computationally checkable surface. Those claims can be preserved differently. They can be run. They can be tested. They can fail when precision is wrong.&lt;/p&gt;
&lt;p&gt;That is the narrow role of an executable reproduction artifact: not proof replacement, not automated peer review, and not authority over the theorem, but a reproducible object for the part of the claim that can be computed.&lt;/p&gt;
&lt;hr&gt;
&lt;h3 id=&quot;the-specific-target-equation-2-2-&quot;&gt;The specific target: equation (2.2)&lt;/h3&gt;
&lt;p&gt;In the OpenAI Erdős result, one checkable surface is equation (2.2) of the remarks paper.&lt;/p&gt;
&lt;p&gt;For the explicit choice&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=7138879423288234316&quot; alt=&quot;math1&quot;&gt;&lt;/p&gt;
&lt;p&gt;the remarks paper gives an explicit numerical lower bound on the exponent excess above the classical Erdős exponent:&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=13849924454096937923&quot; alt=&quot;math2&quot;&gt;&lt;/p&gt;
&lt;p&gt;These parameters are taken directly from the remarks paper without modification. The artifact does not derive the multiquadratic choice; it reproduces the finite numerical calculation built from that choice.&lt;/p&gt;
&lt;p&gt;This is not the later stronger explicit bound associated with Sawin’s separate preprint. It is not $\delta \approx 0.014$. It is the numerical value appearing in equation (2.2) of the remarks paper.&lt;/p&gt;
&lt;p&gt;That narrowness is important. It is exactly what makes the claim suitable for executable reproduction.&lt;/p&gt;
&lt;hr&gt;
&lt;h3 id=&quot;where-the-numerical-fragility-comes-from&quot;&gt;Where the numerical fragility comes from&lt;/h3&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=4133600104991436468&quot; alt=&quot;4&quot;&gt;&lt;/p&gt;
&lt;p&gt;The numerical fragility comes from the exact form of equation (2.2), not from a large computation.&lt;/p&gt;
&lt;p&gt;Immediately after the published expression, the parameters are:&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=7110299839676694670&quot; alt=&quot;math3&quot;&gt;&lt;/p&gt;
&lt;p&gt;and&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=483384573840666881&quot; alt=&quot;math 4&quot;&gt;&lt;/p&gt;
&lt;p&gt;With the paper’s definitions of $u, v$, and $\delta$  substituted into equation (2.2), the exponent excess reduces to:&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=2715587953765822422&quot; alt=&quot;math5&quot;&gt;&lt;/p&gt;
&lt;p&gt;The constant $36$ is not introduced by the implementation. It is already present in the remarks paper’s equation (2.2), both in the numerator term $u\pi/(36v)$ and in the denominator term $\log(36/\delta^2).$&lt;/p&gt;
&lt;p&gt;After substituting $u = K/r^2, v = r/2$, and $\delta = 101^{-2K}$, the numerator simplifies to $\log(K\pi / 18r^3)$, while the denominator becomes $\log 36 + 4K \log 101$.&lt;/p&gt;
&lt;p&gt;Here the $101$ comes from the finite prime in $S = {101, \infty}$.&lt;/p&gt;
&lt;p&gt;In other words, this artifact does not derive the constant $36$ from first principles; it reproduces the published equation with the stated substitutions.&lt;/p&gt;
&lt;p&gt;The precision problem is in the numerator:&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=11575553626952662327&quot; alt=&quot;math 7&quot;&gt;&lt;/p&gt;
&lt;p&gt;Because $K$ is the ceiling of $18r^3 / \pi$, the ratio $K\pi / 18r^3$ is only barely larger than $1$.&lt;/p&gt;
&lt;p&gt;More precisely:&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=10827487014404388139&quot; alt=&quot;math8&quot;&gt;&lt;/p&gt;
&lt;p&gt;For $r = 510510$,&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=13091608971449808775&quot; alt=&quot;math 9&quot;&gt;&lt;/p&gt;
&lt;p&gt;So the numerator is effectively $\log(1 + \varepsilon)$ with $\varepsilon$ at the  $10^{-18}$scale.&lt;/p&gt;
&lt;p&gt;IEEE 754 double precision has machine epsilon around $2.2 \times 10^{-16}$. A naive &lt;code&gt;float64&lt;/code&gt; computation therefore cannot reliably distinguish the near-one ratio from  $1$. The ratio rounds to $1$, leading to $\log(1) = 0.$&lt;/p&gt;
&lt;p&gt;The exponent excess disappears before the computation reaches the value stated in the paper.&lt;/p&gt;
&lt;p&gt;This is not a flaw in the mathematics. It is a precision failure in the numerical evaluation of a valid expression. That is the reason the artifact evaluates equation (2.2) using &lt;code&gt;mpmath&lt;/code&gt; at 200-bit precision.&lt;/p&gt;
&lt;p&gt;A PDF can state the value. A verifier can expose when the value disappears.&lt;/p&gt;
&lt;hr&gt;
&lt;h3 id=&quot;what-we-built&quot;&gt;What we built&lt;/h3&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=9321543817991300315&quot; alt=&quot;last&quot;&gt;&lt;/p&gt;
&lt;p&gt;We built:&lt;/p&gt;
&lt;p&gt;&lt;a rel=&quot;nofollow&quot; href=&quot;https://github.com/Flamehaven-Labs/openai-erdos-eq22-reproduction&quot;&gt;https://github.com/Flamehaven-Labs/openai-erdos-eq22-reproduction&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;The purpose is deliberately narrow: reproduce the finite, explicitly checkable numerical surface of equation (2.2) in the OpenAI Erdős unit-distance disproof remarks.&lt;/p&gt;
&lt;p&gt;The package evaluates the expression using &lt;code&gt;mpmath&lt;/code&gt; at 200-bit precision and returns:&lt;/p&gt;
&lt;pre&gt;&lt;code&gt;6.2391e-38
&lt;/code&gt;&lt;/pre&gt;
&lt;p&gt;This matches the published two-significant-figure value $\approx 6.24 \times 10^{-38}$ to $1.4 \times 10^{-4}$ relative error.&lt;/p&gt;
&lt;p&gt;The repository includes 60 unit tests, 21 verifier checks, a frozen per-source-file SHA-256 manifest, GitHub Actions CI across Ubuntu and Windows, Python 3.11 / 3.12 verification, and a frozen-report mode that prints a verdict without mutating tracked evidence.&lt;/p&gt;
&lt;p&gt;The basic reproduction path is:&lt;/p&gt;
&lt;pre&gt;&lt;code class=&quot;language-bash&quot;&gt;git clone &amp;lt;https://github.com/Flamehaven-Labs/openai-erdos-eq22-reproduction&amp;gt;
cd openai-erdos-eq22-reproduction
pip install -e &quot;.[dev]&quot;
python -m erdos_ant.verify
&lt;/code&gt;&lt;/pre&gt;
&lt;p&gt;Expected output includes:&lt;/p&gt;
&lt;pre&gt;&lt;code&gt;Verdict: PASS
Checks: 21/21 passed
eq (2.2) exponent excess: 6.2391e-38
&lt;/code&gt;&lt;/pre&gt;
&lt;p&gt;This is not a large system. That is part of the point. A small claim with a clear boundary is easier to inspect than a broad claim that blurs proof, computation, and interpretation.&lt;/p&gt;
&lt;hr&gt;
&lt;h3 id=&quot;from-reproduction-to-custody&quot;&gt;From reproduction to custody&lt;/h3&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=9085427059880693022&quot; alt=&quot;2&quot;&gt;&lt;/p&gt;
&lt;p&gt;This repository was not built as a one-off reaction to an OpenAI announcement. We are not announcing a grand framework here; we are showing the discipline in miniature.&lt;/p&gt;
&lt;p&gt;For us, the work is part of a longer routine: take a mathematical or technical claim, isolate the checkable surface, pin the environment, and make drift visible.&lt;/p&gt;
&lt;p&gt;That is intentionally plain work.&lt;/p&gt;
&lt;p&gt;Read the source.&lt;/p&gt;
&lt;p&gt;Extract the claim.&lt;/p&gt;
&lt;p&gt;Reproduce the computation.&lt;/p&gt;
&lt;p&gt;Record the boundary.&lt;/p&gt;
&lt;p&gt;Let the verifier fail if the result disappears.&lt;/p&gt;
&lt;p&gt;To execute this routine reliably, the scope must be uncomfortably narrow. This repository intentionally leaves the proof of Theorem 1.1, the construction of the infinite tower, and Sawin’s separate $\delta \approx 0.014$  preprint to their respective sources. It does not pretend to be peer review.&lt;/p&gt;
&lt;p&gt;This is not just a disclaimer. It is the point of the artifact.&lt;/p&gt;
&lt;p&gt;A sharp, restricted boundary is exactly what makes a claim inspectable, repeatable, and challengeable. This is what I mean here by claim custody.&lt;/p&gt;
&lt;p&gt;It addresses a technical governance question, but not in the policy sense: what exactly is being trusted, from which source, and what makes the claim fail if the implementation changes?&lt;/p&gt;
&lt;blockquote&gt;&lt;p&gt;&lt;strong&gt;A PDF can state the value. A verifier can expose when the value disappears.&lt;/strong&gt;&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;We claim no authority over the broader theorem. We simply maintain a reproducible boundary around the fragile numerical claim inside it.&lt;/p&gt;
&lt;hr&gt;
&lt;h3 id=&quot;closing&quot;&gt;Closing&lt;/h3&gt;
&lt;p&gt;&lt;img src=&quot;https://coderlegion.com/?qa=blob&amp;amp;qa_blobid=9984717360298612367&quot; alt=&quot;repo&quot;&gt;&lt;/p&gt;
&lt;p&gt;The theorem was proved in the mathematical papers.&lt;/p&gt;
&lt;p&gt;This repository asks a smaller question: can the numerical value in equation (2.2) survive execution?&lt;/p&gt;
&lt;p&gt;In &lt;code&gt;float64&lt;/code&gt;, it does not. The exponent excess collapses to zero.&lt;/p&gt;
&lt;p&gt;At 200-bit precision, with the source parameters pinned and the verifier running under CI, the artifact recovers:&lt;/p&gt;
&lt;pre&gt;&lt;code&gt;6.2391e-38
&lt;/code&gt;&lt;/pre&gt;
&lt;p&gt;matching the published value to $1.4 \times 10^{-4}$ relative error.&lt;/p&gt;
&lt;p&gt;That is the point.&lt;/p&gt;
&lt;p&gt;Not a new theorem. Not a proof replacement.&lt;/p&gt;
&lt;p&gt;A reproducible claim surface for one precision-sensitive number in a major AI-assisted mathematical result.&lt;/p&gt;
&lt;p&gt;Repository:&lt;/p&gt;
&lt;p&gt;&lt;a rel=&quot;nofollow&quot; href=&quot;https://github.com/Flamehaven-Labs/openai-erdos-eq22-reproduction&quot;&gt;https://github.com/Flamehaven-Labs/openai-erdos-eq22-reproduction&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;Paper / Zenodo:&lt;/p&gt;
&lt;p&gt;&lt;a rel=&quot;nofollow&quot; href=&quot;https://doi.org/10.5281/zenodo.20383217&quot;&gt;https://doi.org/10.5281/zenodo.20383217&lt;/a&gt;&lt;/p&gt;
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<pubDate>Tue, 26 May 2026 06:28:06 +0000</pubDate>
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