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arXiv · 1409.0972

Cycles in Oriented 3-graphs

Imre Leader·Ta Sheng Tan
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Abstract

An oriented 3-graph consists of a family of triples (3-sets), each of which is given one of its two possible cyclic orientations. A cycle in an oriented 3-graph is a positive sum of some of the triples that gives weight zero to each 2-set. Our aim in this paper is to consider the following question: how large can the girth of an oriented 3-graph (on $n$ vertices) be? We show that there exist oriented 3-graphs whose shortest cycle has length $\frac{n^2}{2}(1+o(1))$: this is asymptotically best possible. We also show that there exist 3-tournaments whose shortest cycle has length $\frac{n^2}{3}(1+o(1))$, in complete contrast to the case of 2-tournaments.

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Imre Leader, Ta Sheng Tan. 2014-09-03. Cycles in Oriented 3-graphs. https://arxiv.org/abs/1409.0972

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