Claims

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1987_12_01_fan: Fan (Discrete Math. 67 (1987)) proves that a diameter 2-critical graph on n vertices has at most [n^2/4] edges for n at most 24 and for n = 26, the inequality only; accepted on the refereed publication.

1988_03_01_furedi: Füredi (J. Graph Theory 1992) proves that a diameter-two graph in which deleting any edge raises the diameter has at most floor(n^2/4) edges once n exceeds a tower-type threshold; accepted on the refereed publication.

2026_08_05_jstar: A proof claim on the site's proof-claim tab asserts the bound floor(n^2/4) for every n by an induction on a deficiency count defined for all graphs, with a Lean file; AI-generated by its submitter's account, and unreviewed.

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