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On Zarankiewicz's bounds for valued vector spaces

Logic 2026-07-18 v1 Combinatorics

Abstract

We establish absolute and relative almost-linear Zarankiewicz bounds for semilinear relations in valued vector spaces. For every fixed arity and description complexity, a Kt,,tK_{t,\ldots,t}-free semilinear rr-partite hypergraph has at most O ⁣(nr1(logn)c) O\!\left(n^{r-1}(\log n)^c\right) edges, where cc depends only on the arity and the number of valuative literals. In the bipartite case a separate arbitrary-trace argument gives the explicit bound O(n(logn)2s)O(n(\log n)^{2s}) for description complexity (ρ,s)(\rho,s). We also prove a relative extension theorem: intersecting any relation with a hereditary almost-linear profile by ss affine moving-radius comparisons increases the logarithmic exponent by at most 2s2s. For the additive affine-valuative structures on Qp\mathbb Q_p and Cp\mathbb C_p, quantifier elimination converts these semilinear results into bounds for all definable relations. Finally, over every valued field with infinite value group, we construct K2,2K_{2,2}-free semilinear point--box graphs of description complexity (1,4)(1,4) with Ω(nlogn/loglogn)\Omega(n\log n/\log\log n) edges.

Cite

@article{arxiv.2607.16772,
  title  = {On Zarankiewicz's bounds for valued vector spaces},
  author = {Hongyi Gou and Mihir Mittal and Chieu-Minh Tran and Zhenyu Yang},
  journal= {arXiv preprint arXiv:2607.16772},
  year   = {2026}
}

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24 pages