Kelly's minimum semi-degree conjecture for directed cycles

From papers

Let l4l\geq 4 be an integer, and let kk be the smallest integer greater than 22 that does not divide ll. Let δ0(G)\delta^0(G) denote the minimum semi-degree of an oriented graph GG. Kelly's conjecture. There exists n0n_0 such that every oriented graph GG on nn0n\geq n_0 vertices satisfying

δ0(G)nk+1\delta^0(G)\geq \left\lfloor\frac{n}{k}\right\rfloor+1

contains a copy of the directed cycle ClC_l. The conjecture concerns the semi-degree threshold forcing directed cycles of length at least four; the source gives no resolution status.

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Sources & referencesView supporting material

Primary source

Ming Chen, Wenxu Lu, Yun Wang and Zhiwei Zhang, “Turán-type and tiling problems in oriented graphs”, arXiv:2603.21971 (2026).

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