Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.
Updated
Claim. Every tournament on vertices contains a transitive subtournament on vertices (Theorem 4, printed p. 235), so , while the conjectured formula of Problem 1216 gives ; one such refutes the formula, so the answer to the question is no. The paper also gives a -vertex tournament with no transitive -subtournament (pp. 235--236), so exactly and the directed Ramsey number is , and its Corollary 2 (p. 235) gives for every , which exceeds for in for each . The paper states the conjecture in the equivalent form that for each some tournament on vertices has no transitive -subtournament and shows it false for every . The source is the library's source card, for the publisher's open-archive version. What the disproof leaves open, the exact value of for and from on and the asymptotic constant between and , is recorded on the problem page and is not part of this claim.
Depends on. Nothing in this wiki; the result is the paper's own theorem.
Dating. The page is dated by the issue month of the journal record (J. Combinatorial Theory 9 (1970), no. 3, October 1970, per the Crossref record); the day in the page name is a placeholder. The paper was received in August 1968 (p. 225).
Acceptance. Reviewed: the site's curator, T. F. Bloom, labels the problem DISPROVED and credits Reid and Parker in the problem's commentary with the negative answer for every (page last edited 12 April 2026); the curator neither submitted nor co-wrote the result and is independent of the authors, and the community database records the problem disproved (last updated 21 April 2026). The site's "for every " overstates the result: the formula holds again for (the paper's own values, p. 236) and for , and fails for infinitely many , as the problem page records. Refereed: J. Combinatorial Theory 9 (1970), no. 3, 225--238, communicated by Leo Moser. The theorem is attested by two later refereed sources: the survey paragraph of Ihringer, Rajendraprasad and Weinert (Discrete Math. 2021, p. 2) and Table 1 of McCarthy and Monico (Electron. J. Combin. 2025, p. 7) both cite to the paper. Nagy's introduction (in the author-hosted copy; no journal record found in Crossref) names the paper as the disproof of the conjecture, and Neumann-Lara's shorter proof of Corollary 1 (Graphs Combin. 10 (1994), 363--366) has its own claim page; these attestations are beside the evidence listed above.
Read depth. Claims checked: Theorem 4 and Corollaries 1--2 on p. 235, and the -vertex witness on pp. 235--236, whose automorphisms reduce the check to one cyclic triple, , for the arcs with difference in ; the arcs with difference in form a second orbit, mapped to , and has only two elements, so no lies above them either (the paper states only the first triple). The proof of Theorem 4 was followed as a reduction to the paper's Theorems 2 and 3; the case analysis proving Theorem 3 (pp. 227--235) was read for structure only and not checked, and nothing is independently reviewed in this corpus.