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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. V. Neumann-Lara, A short proof of a theorem of Reid and Parker on tournaments, Graphs Combin. 10 (1994), no. 2--4, 363--366, gives a shorter proof of Reid and Parker's theorem that for k≥5k\ge5 and n≥7⋅2k−4n\ge7\cdot2^{k-4} every tournament of order nn contains a transitive subtournament of order kk; this is the paper's result as the zbMATH review (Zbl 0811.05028, by B. Alspach) states it. At k=5k=5 every tournament on 1414 vertices contains a transitive subtournament on 55 vertices, so f(14)≥5f(14)\ge5 while the formula of Problem 1216 gives ⌊log⁡214⌋+1=4\lfloor\log_214\rfloor+1=4, and the answer to the question is no. The theorem reproved is Corollary 1 of Reid and Parker, recorded on their claim page; this page records the independent proof.

Depends on. Nothing in this wiki; the proof is the paper's own.

Source. The page is dated by the issue month of the journal record (Graphs and Combinatorics 10, no. 2--4, June 1994, per Crossref); the day in the page name is a placeholder.

Acceptance. Refereed: Graphs and Combinatorics 10 (1994), no. 2--4, 363--366. The site's commentary does not cite this paper, so no reviewed evidence is listed. The proof is not checked in this corpus.