English

Blocking sets from a union of plane curves

Algebraic Geometry 2025-10-20 v1 Combinatorics Number Theory

Abstract

Motivated by a question of Erd\H{o}s on blocking sets in a projective plane that intersect every line only a few times, several authors have used unions of algebraic curves to construct such sets in P2(Fq)\mathbb{P}^2(\mathbb{F}_q). In this paper, we provide new constructions of blocking sets in P2(Fq)\mathbb{P}^2(\mathbb{F}_q) from a union of geometrically irreducible curves of a fixed degree dd. We also establish lower bounds on the number of such curves required to form a blocking set. Our proofs combine tools from arithmetic geometry and combinatorics.

Keywords

Cite

@article{arxiv.2510.15332,
  title  = {Blocking sets from a union of plane curves},
  author = {Shamil Asgarli and Dragos Ghioca and Chi Hoi Yip},
  journal= {arXiv preprint arXiv:2510.15332},
  year   = {2025}
}

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14 pages