Bondy's small cycle double cover conjecture

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A cycle double cover of a graph is a list of cycles such that every edge belongs to exactly two of them. A graph is simple if it has no loops or parallel edges, and 22-edge-connected if deleting any one edge leaves it connected.

Bondy's small cycle double cover conjecture. Every simple 22-edge-connected graph on nn vertices has a cycle double cover consisting of at most n−1n-1 cycles.

The bound is best possible for complete graphs. The source notes that this conjecture does not follow immediately from its proof of the cycle double cover theorem.

References

Primary source

Sang-il Oum, “A proof of the cycle double cover conjecture by OpenAI: An exposition”, arXiv:2607.16356 (2026).

Additional references

5 papers in this index state this conjecture (2014–2026). The statement above is taken from the most recent of them; the others are arXiv:2606.03696, arXiv:2503.15950, arXiv:1705.07066, arXiv:1402.4268.

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