Uniformly discrete Lipschitz-free space with AP but no BAP
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Theorem selected for verification:OAI.DiscreteFree.source_endpoints
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Definitions needed to read it
Local definitions the statement names, followed through the definitions they name in turn. The match is by name in the source text, so a name reached only through notation can be missed; the full file is below.
deflipSubmodule (o : M) : Submodule ℝ (M → ℝ) where
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carrier := {f | f o = 0 ∧ ∃ C : ℝ, 0 ≤ C ∧ ∀ x y, |f x - f y| ≤ C * dist x y} zero_mem' := by refine ⟨rfl, 0, le_rfl, ?_⟩ intro x y simp add_mem' := by rintro f g ⟨hfo, C, hC, hf⟩ ⟨hgo, D, hD, hg⟩ refine ⟨by simpa using congrArg₂ (· + ·) hfo hgo, C + D, add_nonneg hC hD, ?_⟩ intro x y change |f x + g x - (f y + g y)| ≤ (C + D) * dist x ycalc _ = |(f x - f y) + (g x - g y)| := by ring_nf _ ≤ |f x - f y| + |g x - g y| := abs_add_le _ _ _ ≤ C * dist x y + D * dist x y := add_le_add (hf x y) (hg x y) _ = _ := by ring smul_mem' := by rintro c f ⟨hfo, C, hC, hf⟩ refine ⟨by simp [hfo], |c| * C, mul_nonneg (abs_nonneg c) hC, ?_⟩ intro x y change |c * f x - c * f y| ≤ (|c| * C) * dist x ycalc _ = |c| * |f x - f y| := by rw [← mul_sub, abs_mul] _ ≤ |c| * (C * dist x y) := mul_le_mul_of_nonneg_left (hf x y) (abs_nonneg c) _ = _ := by ring
defslope (o : M) : Lip0 o →ₗ[ℝ] lp (fun _ : M × M => ℝ) ∞ where
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toFun f := ⟨fun z : M × M => (f z.1 - f z.2) / dist z.1 z.2, byobtain ⟨C, hC, hf⟩ := f.property.2 apply memℓp_infty refine ⟨C, ?_⟩ rintro r ⟨⟨x, y⟩, rfl⟩ change ‖(f x - f y) / dist x y‖ ≤ C rw [Real.norm_eq_abs, abs_div, abs_of_nonneg dist_nonneg] by_cases hxy : x = y · simp [hxy, hC] · exact (div_le_iff₀ (dist_pos.mpr hxy)).2 (hf x y)⟩ map_add' f g := by apply lp.ext funext z change ((f z.1 + g z.1) - (f z.2 + g z.2)) / dist z.1 z.2 = (f z.1 - f z.2) / dist z.1 z.2 + (g z.1 - g z.2) / dist z.1 z.2 ring map_smul' c f := by apply lp.ext funext z change (c * f z.1 - c * f z.2) / dist z.1 z.2 = c * ((f z.1 - f z.2) / dist z.1 z.2) ring
defBlockStatement : Prop := ∀ p : ℕ, 1 ≤ p → ∃ (M : Type) (d : MetricSpace M) (o : M),letI := d Countable M ∧ (∀ x y : M, x ≠ y → 1 ≤ dist x y) ∧ (∀ x y : M, dist x y ≤ blockBound p) ∧ ∃ A : Finset M, o ∈ A ∧ ∀ T : FreeSpace o →L[ℝ] FreeSpace o, Module.Finite ℝ (LinearMap.range T.toLinearMap) → ‖T‖ ≤ (p : ℝ) → ∃ a ∈ A, (1 / 2 : ℝ) ≤ ‖T (delta o a) - delta o a‖
defMainStatement : Prop := ∃ (M : Type) (d : MetricSpace M) (o : M),letI := d Countable M ∧ (∀ x y : M, x ≠ y → 1 ≤ dist x y) ∧ (¬ Bornology.IsBounded (Set.univ : Set M)) ∧ (¬ ProperSpace M) ∧ HasAP (FreeSpace o) ∧ ∀ Λ : ℝ, 1 ≤ Λ → ¬ HasBAP (FreeSpace o) Λ
Possible paper match, with no recorded review
Atlas selected this possible match by comparing words in the Lean statement with every statement in the family. No review of whether the statements mean the same thing is recorded.
Words of the Lean statement, its names split into words, that also appear in the theorem: ap, finite, countable, metric, bap and space. Found in the paper’s title, which its main theorem states: free and bounded. Shared only with the release’s name for the Lean statement or OpenAI’s note on it: unbounded, distinct, fails and pointed.
Theorem 1.1 of A uniformly discrete counterexample to bounded approximation in Lipschitz-free spaces
Theorem
There is a countable, unbounded, nonproper pointed metric space (M,d,o) such that d(x,y)\ge1 for distinct points and \F(M) has AP but fails \lambda-BAP for every finite \lambda\ge1.
There is a countable, unbounded, nonproper pointed metric space $(M,d,o)$
such that $d(x,y)\ge1$ for distinct points and $\F(M)$ has AP but fails
$\lambda$-BAP for every finite $\lambda\ge1$.
Other possible paper matches, closest wording first
Proposition 2.1 of A uniformly discrete counterexample to bounded approximation in Lipschitz-free spaces. Words of the Lean statement, its names split into words, that also appear in the theorem: zero, map, delta, countable, linear, 1/2 and four more. Shared only with the release’s name for the Lean statement or OpenAI’s note on it: distinct and pointed.
Theorem 1.2 of A uniformly discrete counterexample to bounded approximation in Lipschitz-free spaces. Words of the Lean statement, its names split into words, that also appear in the theorem: finite, delta, bounded, integer, linear, 1/2 and three more. Shared only with the release’s name for the Lean statement or OpenAI’s note on it: pointed.
Corollary 1.3 of A uniformly discrete counterexample to bounded approximation in Lipschitz-free spaces. Words of the Lean statement, its names split into words, that also appear in the theorem: real, map, integer, 1/2, norm and bap. Shared only with the release’s name for the Lean statement or OpenAI’s note on it: fails.
How Atlas selects possible matches: it compares words in the Lean statement with every statement in the family. It also splits Lean names into words. The release’s label and note receive less weight; a main theorem wins a close match. If the Lean wording yields no clear match, Atlas uses the catalogue description. This selects passages to compare; it does not establish that they mean the same thing.
Reported Comparator runs
three independent groups report that Comparator accepted runs for this Lean statement file: Carlos Toledo’s cert-machine; MathVet; Neal McBurnett’s openai-math-lean-tooling. Each group reports its own Comparator run for this statement file. Atlas has not repeated the runs.
For a configured theorem, Comparator tests whether OpenAI’s proof proves the exact Lean statement. Some files instead configure definitions for comparison by name and type. Acceptance does not establish that the statement means the same thing as the paper’s theorem.
Every Comparator challenge re-run on Linux with nanoda switched on, decided by a preregistered rule; every family’s challenge statements read against OpenAI’s headline, clause by clause. Decider: Comparator (leanprover/comparator d03acab1 = tag v4.34.0, built with the release’s toolchain v4.34.1), lean4export 076e8e57, landrun 811cfff5, nanoda_lib 3a240721 — on GitHub’s Linux runners (.github/workflows/openai-math-kernel.yml), one j…
AcceptedTheir term: “CERTIFIED”.
Re-run through Comparator with the independent nanoda kernel switched on: Lean’s kernel and nanoda both accept OpenAI’s solution.
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. Its protocol describes a planned error-rate study; this import does not establish that the study has been completed.
AcceptedTheir term: “comparator-sandboxed-pass”.
Re-run through Comparator in a sandboxed virtual machine: accepted.
Each challenge’s solution is built and checked by Comparator at the pinned release, on Lean leanprover/lean4:v4.34.1, recording the verdict, the check time and the peak memory; the run was still in progress at this snapshot (192 accepted, 224 pending).
AcceptedTheir term: “accepted”.
Re-run through Comparator with Lean’s kernel: accepted (the check took 86 s; peak memory 6.2 GiB).
If Comparator is run under this configuration and accepts, the solution proves the configured theorem using only the allowed axioms, and the Lean kernel accepts every step.
This configuration lists no definition holes, so every definition the statement uses is compared as it is written in this file.
Acceptance leaves open whether the Lean statement means the same thing as the paper’s theorem, whether the paper’s other claims are correct, and whether the result is new. Those questions require comparing the definitions and statements, reviewing the paper’s arguments, and reading the earlier literature.
Do family 330’s Lean statements express the advertised result?
These assessments compare all the family’s Lean statements with the whole result OpenAI describes in its catalogue. They do not assess this statement alone. Each group uses its own published rules.
MathVet and cert-machine agree on how much of the advertised result the Lean statements express.
Finds the whole advertised result stated or impliedTheir term: “full”.
The challenge statements imply the headline claim after unpacking definitions or one routine step. Their record
Their note: MainStatement (inside source_endpoints) gives a countable metric space M with all distinct distances ≥ 1, unbounded and not proper, such that the real Lipschitz-free space FreeSpace o has HasAP but ¬ HasBAP for every Λ ≥ 1, exactly the summary; BlockStatement (finite quantitative blocks) and the ℓ¹ renorming with 2B_p-BAP but not p-BAP are the retained earlier results.
Definitions the group asks readers to compare with the paper: FreeSpace o := closure of span {evaluation o x} ⊆ (Lip0 o →L[ℝ] ℝ) with Lip0 o normed by the slope map into ℓ^∞(M × M): hand-built Lipschitz-free space, standard; HasAP/HasBAP state approximation of the identity on every compact set by finite-rank operators (with ‖T‖ ≤ Λ for BAP)
OpenAI’s own note on what this Lean statement covers
“The formalization constructs a countable metric space with all distinct points at distance at least one whose real Lipschitz-free space has the approximation property but fails every bounded approximation bound. The metric space is unbounded and not proper.”
An AI agent drafted an interpretation of that note, classifying this statement as “states a paper’s theorem as the paper does”. No human review of the draft is recorded.
Supporting material
The complete Lean statement file
163 lines, copied from release version fd4aeeb. A name defined in this file links to its line; pointing at the name shows its definition.
Declared in this fileOpenAI’s library at fd4aeebOther linked names open the current documentation for Mathlib, Lean’s mathematical library.
Links in the file: 35 to its own declarations, 109 to Mathlib’s documentation. 13 declared names also link to the same declaration in OpenAI’s library. 4 identifiers stay plain because they resolve to no single declaration: variables Lean binds automatically, notation, or names the scan of the pinned sources did not find. OpenAI uses Mathlib version d13f23b. The linked documentation describes the current version, so names that have since changed may be missing there.
There is a countable, unbounded, nonproper pointed metric space (M,d,o) such that d(x,y)\ge1 for distinct points and \F(M) has AP but fails \lambda-BAP for every finite \lambda\ge1.
There is a countable, unbounded, nonproper pointed metric space $(M,d,o)$
such that $d(x,y)\ge1$ for distinct points and $\F(M)$ has AP but fails
$\lambda$-BAP for every finite $\lambda\ge1$.
Theorem
For each integer p\ge1, there are a bounded countably infinite pointed metric space (M_p,d_p,o) and a finite set A_p\subseteq M_p containing o such that
For each integer $p\ge1$, there are a bounded countably infinite pointed
metric space $(M_p,d_p,o)$ and a finite set $A_p\subseteq M_p$ containing
$o$ such that
\[
d_p(x,y)\ge1\quad(x\ne y),\qquad
\operatorname{diam}M_p\le B_p:=300p^2+150p+5,
\]
and every bounded finite-rank linear operator
$T_0:\F(M_p)\to\F(M_p)$ with $\norm{T_0}\le p$ satisfies
\[
\max_{a\in A_p}\norm{T_0\delta_a-\delta_a}\ge\frac12.
\]
Corollary
For each integer p\ge1, real \ell_1 has an equivalent norm \norm{\cdot}_p such that
\tfrac12\norm{c}_1\le\norm{c}_p\le B_p\norm{c}_1,
and (\ell_1,\norm{\cdot}_p) has 2B_p-BAP but fails p-BAP. For p=1, this norm fails MAP.
For each integer $p\ge1$, real $\ell_1$ has an equivalent norm
$\norm{\cdot}_p$ such that
\[
\tfrac12\norm{c}_1\le\norm{c}_p\le B_p\norm{c}_1,
\]
and $(\ell_1,\norm{\cdot}_p)$ has $2B_p$-BAP but fails $p$-BAP.
For $p=1$, this norm fails MAP.
OpenAI’s Lean catalogue does not list this as a main result; the release’s Lean notes for family 330 link it.
Solution module
OAI.Analysis.LipschitzFree.Main
Allowed axioms
propext, Quot.sound, Classical.choiceThe axioms this configuration allows a proof to use. A replay shows which of them a proof uses.
Imports
Mathlib
Imports from outside Mathlib
None
Local vocabulary
19 local vocabulary declarations
Lines of Lean, without comments or blank lines
118
Second proof-verification program (nanoda)
Off in OpenAI's configuration.
Statement comparison
A shareable summary of this page: the proposed paper match, what the Lean statement expresses, and which reviews are recorded.
Plectis Atlas
Uniformly discrete Lipschitz-free space with AP but no BAP
Family 330: A uniformly discrete counterexample to bounded approximation in Lipschitz-free spaces
Candidate pairing
Theorem
There is a countable, unbounded, nonproper pointed metric space (M,d,o) such that d(x,y)\ge1 for distinct points and \F(M) has AP but fails \lambda-BAP for every finite \lambda\ge1.
A uniformly discrete counterexample to bounded approximation in Lipschitz-free spaces
TeX label thm:main, build/sections/introduction.tex, line 39
A Lean statement states the theorem and leaves its proof as sorry on purpose. OpenAI’s proof is in a separate solution module, and a program called Comparator checks that proof against this statement.
Recorded comparisons with the paper
Atlas records no contributed comparison of this statement with the paper.
Contributed Comparator run reports
Atlas records no contributed report of running Comparator for this statement file.