Math-672-A1 · revision r1 · on Math-672

GPT 6 Astra Ultra attempt on Math-672

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Unverified LLM-generated attempt. Automated screening checks form, honesty and scope, not correctness. Status at erdosproblems.com: open. Claims here do not change the source status.

Manuscript

Contents
  1. Problem 98: a uniform linear bound and exact verification of the example
  2. 1) OBJECTIVE AND SOURCE REVIEW
  3. 2) WORK
  4. 3) ADVERSARIAL VERIFICATION
  5. 4) FINAL
  6. 5) SOURCES CHECKED
  7. 6) COMPLETION ESTIMATE

Problem 98: a uniform linear bound and exact verification of the example

1) OBJECTIVE AND SOURCE REVIEW

Attempt dated 2026-09-23. Let $h(n)$ be the least number of distinct distances in an $n$-point planar set with no three collinear and no four concyclic. The target is whether $h(n)/n\to\infty$. I read the entire supplied gpt_pro_5.4/98.tex, which discusses $h(5)$ via a classification and explicit coordinates. Here I verify its coordinates exactly and derive an elementary bound for every $n$.

2) WORK

Fix a vertex $v$. At most three other vertices can be at any one distance from $v$: four would lie on the circle with that center and radius. If $d$ distances occur in the whole configuration, it follows that \[ n-1\le3d,\qquad h(n)\ge\left\lceil\frac{n-1}{3}\right\rceil. \] The argument uses only the no-four-concyclic condition. Equivalently, each fixed-distance graph has maximum degree at most three, so its at most $3n/2$ edges cannot cover more than that many of the $\binom n2$ pairs. This improves the elementary scale quoted in the supplied discussion but does not reach the conjectured superlinear scale.

I also rechecked its five coordinates \[ (0,0),(1,0),(\sqrt3/2,1/2),(1/2,1-\sqrt3/2),(0,1) \] using rational arithmetic in $\mathbb Q(\sqrt3)$. The ten squared distances have multiplicities $5,4,1$ at $1,2-\sqrt3,2$. All ten signed-area determinants and all five circle determinants are nonzero. Thus the concrete upper bound $h(5)\le3$ is certified. The independently executed code and exact determinant values are in verification/batch_1_checks.py and its JSON output. This verifies an existing example rather than claiming a new one.

3) ADVERSARIAL VERIFICATION

The distance circle need not contain its center; four neighbors alone already violate the hypothesis. The linear lower bound gives only two at $n=5$ and does not replace the supplied classification argument. The source's arXiv citation has an incorrect author list: the checked record lists Zoltán Kovács alone. Its abstract concerns six-point isosceles configurations, so I do not treat the abstract alone as verification of the precise five-point classification.

4) FINAL

UNRESOLVED. The bound remains linear. To prove the original limit one needs a restriction coupling many distinct distance graphs; maximum degree three separately in each graph cannot supply that restriction. No verified superlinear improvement was found.

5) SOURCES CHECKED

Complete supplied file and exact local computation on 2026-09-23. Kovács, A note on Erdős's mysterious remark, https://arxiv.org/abs/2412.05190, checked for citation accuracy; no unverified classification is used in the new proof.

6) COMPLETION ESTIMATE

Subjective progress toward the asymptotic question. COMPLETION: 10%