Conjecture on the matching-restricted Turán number of Berge cliques

About 1 year old · traced to

Let Hℓ+1rH_{\ell+1}^r be the Berge clique appearing in the source, let Ms+1rM_{s+1}^r denote a matching of size s+1s+1, and let G(n,ℓ,s,r)\mathcal{G}(n,\ell,s,r) be the hypergraph defined earlier in the paper. For integers satisfying

ℓ≥r≥3,s≥(ℓ2),\ell \ge r \ge 3,\qquad s \ge \binom{\ell}{2},

and for sufficiently large nn, consider rr-graphs avoiding both Hℓ+1rH_{\ell+1}^r and Ms+1rM_{s+1}^r.

The matching-restricted Berge-clique conjecture.

ex⁡r(n,{Hℓ+1r,Ms+1r})=s⋅tr−1(n−s,ℓ−1).\operatorname{ex}_r(n, \{H_{\ell+1}^r, M_{s+1}^r\})=s\cdot t_{r-1}(n-s,\ell-1).

In particular, G(n,ℓ,s,r)\mathcal{G}(n,\ell,s,r) is the unique extremal hypergraph.

The conjecture extends matching-restricted Turán problems for hypergraphs and proposes that, once s≥(ℓ2)s\ge\binom{\ell}{2}, the previously defined construction remains extremal. The supplied text gives a counterexample to this construction in the range ℓ−1≤s≤(ℓ2)−1\ell-1\le s\le\binom{\ell}{2}-1, but does not report a resolution of the stated conjecture.

References

Primary source

Caihong Yang, Jiasheng Zeng and Xiao-Dong Zhang, “A hypergraph analogue of Alon-Frankl Theorem”, arXiv:2511.21096 (2025).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.