English

Anti-Ramsey forbidden poset problems

Combinatorics 2026-03-26 v2

Abstract

A family G\mathcal{G} of sets is a weak copy of a poset PP if there is a bijection f:PGf:P\rightarrow \mathcal{G} such that pqp\leqslant q implies f(p)f(q)f(p)\subseteq f(q). If ff satisfies pqp\leqslant q if and only if f(p)f(q)f(p)\subseteq f(q), the G\mathcal{G} is a strong copy of PP. We study the anti-Ramsey numbers ar(n,P),ar(n,P)\mathrm{ar}(n,P), \mathrm{ar^*}(n,P), the maximum number of colors used in a coloring of 2[n]2^{[n]} that does not admit a rainbow weak or strong copy of PP, respectively. We establish connections to the well-studied extremal numbers La(n,P)\mathrm{La}(n,P) and La(n,P)\mathrm{La^*}(n,P) and determine asymptotically ar(n,T)\mathrm{ar^*}(n,T) for all tree posets TT and ar(n,O2k)\mathrm{ar^*}(n,O_{2k}) for all crown posets O2kO_{2k}.

Keywords

Cite

@article{arxiv.2603.10610,
  title  = {Anti-Ramsey forbidden poset problems},
  author = {Balázs Patkós},
  journal= {arXiv preprint arXiv:2603.10610},
  year   = {2026}
}
R2 v1 2026-07-01T11:14:26.560Z