Hegedüs' conjecture on skew Bollobás systems of projective subspaces

From papers

Let WW be an nn-dimensional projective space over an arbitrary field F\mathbb{F}, and let P={(Ai,Bi)}i=1m\mathcal{P}=\{(A_i,B_i)\}_{i=1}^m be a skew Bollobás system of projective subspaces of WW, meaning that

AiBi=for every i[m],A_i\cap B_i=\emptyset \quad\text{for every }i\in [m],

and

AiBjfor all 1i<jm.A_i\cap B_j\neq\emptyset \quad\text{for all }1\leq i<j\leq m.

Hegedüs' conjecture. Every such system satisfies

m2n+12.m\leq 2^{\,n+1}-2.

Hegedüs proposed this bound in 2015 as a projective-subspace analogue of the skew Bollobás theorem. The supplied source does not state whether the conjecture has been resolved.

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Sources & referencesView supporting material

Primary source

Yongjiang Wu, Yongtao Li, Lu Lu and Lihua Feng, “Subspace variations of the weighted skew Bollobás theorem”, arXiv:2603.02698 (2026).

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