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Updated
Subject and independence
The reviewer is an independent examiner working in a fresh context from the
commissioned assignment alone. The reviewer took no part in writing the
page, its sibling reconstruction pages or the folder's evidence, consulted
no other review, ran no web search, and read nothing under the folder's
evidence/ directory.
Frozen subject: path
wiki/research/erdos_354/yu_chen_theorem_5_1_reconstruction.md as it stood at
2026-09-28T05:03:27Z, read in full as of that time.
Artifact: the seventeen-page PDF held by the library source card Yu and Chen (2026) (the folder-name PDF, 138,329 bytes; physical page numbers coincide with the printed ones). Physical pp. 4--6 (Section 3 with Subsections 3.1--3.3 and displays (3.1), (3.2); Section 4 with (4.1)--(4.3); Section 5 with Theorem 5.1, (5.1), its proof and (5.2)) and p. 17 (Appendix A) were read in full, every display checked against the page image. Physical pp. 2--3 (Section 1, Subsection 1.1, Lemmas 2.1 and 2.2) were read in full for the definitions and the imported lemmas, and p. 1 for the theorem and scope only. Page images rendered and read: pp. 2, 3, 4, 5 and 6 at 110 dpi and p. 17 at 130 dpi.
Allowed material read: the four input pages the page cites, as of the same time
(the normalization page and the Lemma 2.1, 2.2 and 2.3 reconstructions), their
Statement sections as the interface; the provenance paragraph of the library
card; the Statement section of the card's theorem result page; the statement of
Problem 354 on wiki/problems/additive_bases/E0354/_index.md; docs/verification.md
"Whole-claim report" and "Audit checklist"; docs/evidence.md "Source
fidelity"; and docs/math_authoring.md.
Exposures: (1) the library card's _index.md printed whole, so its Read
status, Overview, Standing, Bears on and Results sections reached the
reviewer beyond the provenance paragraph; (2) the problem page has no
Statement heading, and while locating the statement its frontmatter
description, its Formulation paragraph and the opening lines of its Status
paragraph reached the reviewer; (3) the four input pages printed whole, so
their Source, Standing, Definitions and Proof sections reached the
reviewer; only their Statement sections were used, except that the mesh
lemma's proof was glanced at for the bound used in Step 5, which the
Statement alone also gives; (4) a file listing of the folder as of that time
showed the names evidence/_index.md and evidence/main.py; neither was
opened. None of the exposed text entered the verdict.
Restatement
Setting (from the normalization page and pp. 2--3): with and ; weights , ; conversions , , both in ; the set of subset sums of the weights of index below , each used at most once, the empty sum included; their total; ; ; ; . Conventions: for a nonempty residue set, is the length of the longest cyclic run of missing residues, when the set is full; for a finite integer set with at least two elements, span is maximum minus minimum and gap is the largest difference of consecutive elements.
Hypotheses. Fix a layer and write , , , so and, by the interlacing , (whence , ). Put , , , , so . Fix such that for and ; write , , , , and assume . Set .
Conclusion. For every ,
and this holds whatever the values of the conversions at indices are (the conversions at , , enter the construction only through constants bounded by , and later ones only through the doubling bound on the weights). If , then there is an integer such that every integer lies in for some ; that is, the normalized pair is complete.
Length condition. With , the inequality implies ; depends on alone.
Checklist
- Quantifiers and scope. Pass, with one clarification (F1). The conclusion is for all , not eventually; the boundary cases (then and ), , small (excluded by ) and (span of at least directly) are handled on the page. The domain of "every choice of the later conversions" is left implicit; see F1.
- Circularity. None. The proof consumes the three finite lemmas, the certificate table and prefix facts about the normalized pair; no descent or completeness statement enters its own proof.
- Model and convention changes. None. The mesh is an actual subset of , and is the actual residue set. The substitution , is an exact linear reparametrization of the open cone by ; the reviewer checked both directions.
- Finite and statistical overreach. None. The certificate is a finite check of nodes times four third-digit pairs, but each checked object is a linear form whose sign is decided on the whole cone, so the finite table covers every integer pair with . The reviewer re-derived the table independently (Strongest attack).
- Uniformity. Pass. and depend on the layer data and the page says so; the descent bound is uniform in every later conversion; depends on only, and the page states this.
- Extremal conclusions. Inapplicable: the page claims no infimum, supremum, sharpness or attained value. (The reviewer's instances below show that and can be attained, so the bounds are not slack; the page does not claim this either way.)
- Consequences and composition. Pass, with F3. Each "hence" was re-derived: (3.1) to the Claim to (3.2); (4.1) to the nonemptiness and pairwise intersection of the shortened node intervals; (4.2) to (4.3); the mesh lemma to the projection lemma to (5.1); to completeness. The prefix bound is consumed in Step 4 without a citation and is missing from the Scope paragraph's list of inputs (F3).
- Computation. Pass as far as this review reaches. The folder's evidence was excluded and not run. The reviewer's own computation reconstructed the coefficients from the masks of p. 17 under the stated bit order and found no failing instance of conditions 1--3, and simulated three concrete layers with randomized continuations without a violation of (4.2), (4.3) or (5.1).
- Reproduction. Not performed by design: the page's evidence entry point, the source's standalone checker and its Lean kernel evaluation are outside the commissioned read set, and the page claims no rerun line that this review could check. The page's Standing paragraph says the source's checker and Lean evaluation were not replayed, which is consistent with author-recorded standing.
- Source and verdict fidelity. Pass. The statement, hypotheses, displays (3.1), (3.2), (4.1)--(4.3), (5.1), (5.2), the section titles and every locator (pp. 4--6, p. 17, seventeen pages) match the artifact. The Standing paragraph claims author-recorded status only. Two readings are not marked as readings (F1, F4), and supplied steps are not marked (F5).
Weakest steps
W1. The endpoint bounds of Step 2 (why suffices). Let with , where , and . Choose with , so , and . Then
using , and
using . So is an integer in , and (3.1), which needs only (here ), writes it as with . The binary digits of and select distinct block weights , (); uses indices below and indices to ; the three index groups are disjoint, so . The case is the same with and . This composes with the erosion lemma: the residue set has longest missing run , and consecutive integers occupy distinct cyclically consecutive residues, so one of them is present; that is (3.2).
W2. The window cover of Step 4 and . With , and each of , , at least , (4.1) gives , and all at least . Hence each is nonempty and , so is nonempty; by induction on the union is one integer interval, since each new member meets the previous one. Its endpoints are and by condition 3, so it contains , a nonempty interval because . Every window therefore has for some , lies inside , and by (3.2) meets , hence . The window at gives , the window ending at gives , and consecutive in with would leave without a point of . So has at least two elements, and ; with and , one gets .
W3. The chain from the mesh lemma to (5.1). The weights of index at least in increasing order are , each at most twice its predecessor (; as ). Adding them one at a time to produces after the weights of indices below , since . The consequence of the mesh lemma applies because and : every has gap at most , minimum , and span . For this span is at least , since the span before adding was at least (the reviewer checked that this also follows from the statement alone: and , so ); for the span is at least by (4.3). As , the projection lemma with gives , and (its elements use indices below and indices in , disjointly) gives ; a superset of residues has no longer missing run, so . When each is the full interval with , so every integer at least lies in some .
Strongest attack
The only input the page does not prove is the certificate lemma, whose truth the page delegates to a finite check the reviewer could not read. The reviewer therefore attacked it from the artifact alone. From the Appendix A table on p. 17 (text layer, cross-read against the page image) the reviewer reconstructed, for each node , the two subset sums of the six post-block weights under the stated bit order (, , , from the least significant bit; adding neither, , or both), as linear forms in with digit-dependent constants, for all twelve templates and all four third-digit pairs. The table has rows with nodes, in all, hence consecutive links, matching the page and the source. Condition 1 held at every instance with constants at most . For condition 2 the reviewer first proved that the pointwise statement " for all integers " is equivalent to positivity on the open cone of each of the four forms , because a pointwise minimum of finitely many forms is positive at a point exactly when each form is, and a form positive at every integer point of the open cone is nonnegative on the closed cone and not identically zero; then the cone test (, , not both zero, after , ) was applied to the four forms at each of the nodes and the eight forms at each of the links, forms in all (they depend on the masks and , not on the third digits), and the closed-cone test to the two forms of condition 3 at each chain end. No form failed. As a control on the reduction, the min-max inequalities were also evaluated directly at the integer points , , , , , , and , the last three near the cone's two boundary rays; none was violated. One chain, template , was also worked by hand: its nine nodes give equal to , , , , , , , , , with every cross margin one of , , , , or , all positive on the cone, and .
The second attack aimed at the mesh bounds themselves, looking for slack that a wrong constant would expose. At layer with and , so , , , , , , , , , and , the reviewer formed for every template and third-digit pair with randomized ten-digit continuations ( runs): was exactly in the worst run, , and for . At with , modulo , , : the worst gap was and the worst was , the bound attained. At , , : was a full interval and throughout. The bounds are tight and were never crossed, so the attack failed.
A third attack looked for a hidden hypothesis. The candidate was the sorted-order and doubling claim of Step 5 for weights after index under "every choice of the later conversions": if the conversions are abstract digits rather than the actual floors, the normalization page's item 4 does not literally apply. The attack fails because interlacing persists under any digits: from , and . It leaves a clarification (F1), not a defect.
Premises
- Lemma 2.1 (erosion). Interface: for nonempty , . Source held, p. 3, read in full; the reconstruction's Statement read. Applied to , nonempty since , then translated by , which preserves . Imported; the page names it by link and the Scope paragraph counts it among the "three finite lemmas".
- Lemma 2.2 (mesh) with its consequence. Interface: if and then has gap at most and span ; for with and , every iterate keeps gap at most , the same minimum and span . Source held, p. 3, read in full; the reconstruction's Statement read. Hypotheses met by (4.2), (4.3) and the interlacing order. Imported.
- Lemma 2.3 (projection). Interface: if and then . Source held, p. 4, read in full; the reconstruction's Statement read. Applied with . Imported.
- Normalized-pair facts. Interface: ; with the merged list increasing and each term at most twice its predecessor; ; . Source held, pp. 2--3, read in full; the normalization page's Statement read, its proofs not audited here (they are author-recorded reconstructions). The page cites the interlacing but not (F3).
- The certificate table. Interface: the twelve chains of Appendix A satisfy conditions 1--3 of the page's Certificate lemma for all four third-digit pairs and all integers . Source held, p. 17, read in full from the text layer and the page image; independently re-derived by the reviewer (Strongest attack). The page delegates the check to the folder's evidence, which this review did not read.
- Explicit assumptions. The sequences continue forever (an infinite index set); the conversions are digits; the block hypotheses of Section 3 with . No batch acceptance order applies.
Findings
F1. Severity: suggested. Location: Statement, "for every choice of the later conversions". Defect: the domain of the quantifier is implicit. The page's Definitions bind the weights to the fixed normalized pair, under which the later conversions admit exactly one choice, while the source (p. 6, Theorem 5.1) says "for every legal continuation", and the page's own hypotheses call , "arbitrary". Under the free-digit reading, Step 5's sorted-order and doubling claim rests on the normalization page's item 4, proved there for floor sequences only. Witness: p. 6, "for every legal continuation and every "; the page's Step 5, "The weights of indices in sorted order are , each at most twice its predecessor". Proposed replacement: after the Statement add "Here the conversions at indices may be any digits in , the weights being defined from by the recurrences; interlacing persists under any digits, since gives and , so the sorted-order and doubling facts of Step 5 hold for every continuation."
F2. Severity: suggested. Location: Step 4, "". Defect: the symbol is not defined on the page; only , , are. Witness: the page's Definitions define three conversion pairs; by the recurrence of p. 2. Proposed replacement: ", where is the conversion at index , so ."
F3. Severity: suggested. Location: Step 4, "Since is an integer", and Scope, "Its only inputs beyond the three finite lemmas are the certificate table and the interlacing of the normalized pair". Defect: the prefix bound is consumed without a citation and is absent from the Scope paragraph's inventory; it is not a consequence of interlacing but of the column identity (p. 3, end of Subsection 1.1), which the source lists among the Section 3 setup as "" (p. 4). Proposed replacement: in the Hypotheses of Section 3 write "Put and ; then by item 6 of the normalization page", and in Scope "Its only inputs beyond the three finite lemmas are the certificate table, the interlacing and digit bounds of the normalized pair, and the prefix bound ."
F4. Severity: note. Location: Hypotheses of Section 3, "suppose the conversions at indices are zero while the conversion at index is nonzero". Defect: this is a reading of the source's "Use exact doubling pairs at indices " (p. 4), which could also be read as vanishing conversions starting at index ; the page's reading is the one consistent with the displayed weights and the range , and it is the weaker hypothesis, since the proof uses only for . It is not marked as a reading. Proposed replacement: append "(this reads the source's ' exact doubling pairs' as the pairs , , which is all the proof uses)".
F5. Severity: suggested. Location: Source paragraph, and Steps 1, 3 and 6. Defect: the page does not say which steps it supplies, unlike its sibling pages ("the proof below writes them out"). Supplied and unmarked are the remark ; the detailed overlap argument of Step 1 (the source, p. 4, says only "They intersect because "); the reduction of condition 2 to four forms in Step 3 (the source, p. 5, describes the checker's cone inequalities without stating this reduction); the explicit window-intersection inequalities of Step 4; the bound of Step 5; and the whole derivation of in Step 6, which the source states without proof ("Since ", p. 6). Proposed replacement: add to the Source paragraph "The source proves (3.1), (3.2) and (4.1)--(4.3) in a few lines each and states without proof; the proof below supplies the deductions, in particular the four-form reduction of the certificate's condition 2 and the estimate of Step 6."
Verdict
Source fidelity: faithful. The statement, its hypotheses, the displays and every locator match the artifact at pp. 4--6 and 17, and the Standing paragraph claims only author-recorded status; the findings are clarifications of readings, one undefined symbol and an incomplete inventory of inputs, none of which alters the mathematics.
The argument as reconstructed: sound. Every essential deduction was re-derived by the reviewer, the certificate lemma was re-derived independently from the artifact's table with no failing instance, and concrete instances attained the bounds without crossing them.
Limitations: the folder's evidence, the source's standalone checker and its Lean formalization were neither read nor run; the proofs on the normalization and lemma pages were taken at their Statement interfaces and not audited; Sections 6--12 of the manuscript were not read, so how Theorem 5.1 is consumed downstream is outside this review; the reviewer's own computations are retained in this report as derivations, not as repository evidence.
This focused review assigns no tier and changes no status.