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Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.

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Claim. In the letters of Problem 1182, F(n)<84nF(n)<84n for all sufficiently large nn. Brandt proves that for almost every dd-regular graph HH of order nn with d≥168d\ge168 the Ramsey number R(K3,H)R(K_3,H) exceeds 2n2n: the complement of a lexicographic product C5[Kr‾]C_5[\overline{K_r}] on 2n2n or more vertices contains no well-expanding graph, and almost every such HH expands well. Such a graph is connected with 84n84n edges and is not triangle-good, so the threshold F(n)F(n) below which every connected nn-vertex graph is triangle-good is below 84n84n. Since Burr, Erdős, Faudree, Rousseau and Schelp 1980 proved F(n)≥(17n+1)/15F(n)\ge(17n+1)/15 for n≥4n\ge4, the ratio F(n)/nF(n)/n stays between 17/1517/15 and 8484 for large nn and does not tend to infinity. The bound is paged at bound_p7 of the library's source card, which names the copy read, a conversion of the preprint's PostScript that the library does not hold (preprint pp. 4 and 7--8). Brandt adds, without proof, that a refined analysis gives F(n)/n<11.75F(n)/n<11.75 and that he expects 2<F(n)/n<62<F(n)/n<6 for large nn; those are the author's remarks, not part of the claim.

Covers. The closing question of the problem, whether F(n)/n→∞F(n)/n\to\infty: the answer is no. The estimation of F(n)F(n) and f(n)f(n), the problem's main question, is not settled; with this bound F(n)F(n) lies only between 17n/1517n/15 and 84n84n for large nn, and f(n)f(n) only between n3/2(log⁡n)1/2n^{3/2}(\log n)^{1/2} and n3/2log⁡nn^{3/2}\log n up to constants, the upper bound from Sudakov 2007.

Depends on. Burr, Erdős, Faudree, Rousseau and Schelp 1980 for the lower bound that makes the ratio bounded below; the upper bound rests on the cited preprint (bound_p7).

Standing. Claimed. The site's curator, T. F. Bloom, cites Brandt's bound in the commentary as the improvement of the 1980 upper bound and notes that it answers the final question in the negative (page last edited 11 April 2026, after the thread of 14--15 March 2026 in which a reader, unable to find the paper online, reconstructed the preprint in LaTeX and pointed out that the linear bound answers the question). The site labels the problem OPEN, and commentary under that label is not acceptance, so reviewed is not listed. The preprint has no journal version (Crossref bibliographic query, 2026-09-18), so refereed is not listed, and no formalization of the bound is known. The argument is compiled for structure on the library card and not checked; its input on the expansion of random regular graphs is the preprint's Theorem 3.

Postings. The preprint on the Freie Universität Berlin preprint server (PostScript, linked from the site's thread), dated by month only, December 1996, so the day in this page's name and in the link's date is the month's first; the site's problem page and thread. The thread also links a third party's LaTeX reconstruction, which is not the author's posting and is not linked here.