Scott’s conjecture on judicious partitions of 3-uniform hypergraphs

For every fixed integer k≥2k\ge 2, there exists a constant Ck>0C_k>0 such that every 33-uniform hypergraph HH with mm edges has a partition V(H)=V1⊔⋯⊔VkV(H)=V_1\sqcup\cdots\sqcup V_k satisfying e(H[Vi])≤mk3+Ckm2/3e\bigl(H[V_i]\bigr)\le \frac{m}{k^3}+C_k m^{2/3} for every i∈{1,…,k}i\in\{1,\ldots,k\}, where H[Vi]H[V_i] is the subhypergraph induced by ViV_i.

References

Primary source

arXiv

Additional references

Progress summary

Refreshed
Claimed solved

A new preprint claims the conjectured sharp error term for three-uniform hypergraphs, while analogous results in higher uniformities remain open.

Scott’s conjecture predicts sharp judicious partitions of uniform hypergraphs. For the three-uniform case, the latest preprint claims the conjectured error scale, improving the previous bound.

Known results

  • Bollobás and Scott (2000) conjectured that every rr-uniform hypergraph with mm edges admits an rr-partition in which every class meets at least rm2r−1\frac{rm}{2r-1} edges.
  • For r=3r=3, Bollobás and Scott proved the weaker bound 5m−19\frac{5m-1}{9}.
  • Halsegrave and Ma–Yu obtained successive improvements to 0.6m0.6m and 0.65m+o(m)0.65m+o(m).
  • Lin and collaborators (2018) proved the three-uniform bound 1927m−O(m6/7)\frac{19}{27}m-O(m^{6/7}), sharp up to the error term.

October 2026 claimed improvement

Siwei Lin and Qinghou Zeng’s preprint claims an O(m2/3)O(m^{2/3}) error term, matching the conjectured scale and improving O(m6/7)O(m^{6/7}). This would settle the sharp-order error term for the three-uniform case, but the claim has not been independently verified in the retrieved sources.

Current status (as of October 2026): The three-uniform sharp-order error term is claimed solved but remains unverified; analogous conjectures for higher uniformities remain open.

Sources

Solutions 0

No solutions have been posted yet.