Projective and external saturation problem for posets
Abstract
We introduce two variants of the poset saturation problem. For a poset and the Boolean lattice , a family of sets, not necessarily from , is \textit{projective -saturated} if (i) it does not contain any strong copies of , (ii) for any , the family contains a strong copy of , and (iii) for any two different we have . Ordinary strongly -saturated families, i.e., subfamilies required to be from satisfying (i) and (ii), automatically satisfy (iii) as they lie within . We study what phenomena are valid both for the ordinary saturation number and the projective saturation number, the size of the smallest projective -saturated family. Note that the projective saturation number might differ for a poset and its dual. We also introduce an even more relaxed and symmetric version of poset saturation, \textit{external saturation}. We conjecture that all finite posets have bounded external saturation number, and prove this in some special cases.
Keywords
Cite
@article{arxiv.2306.10387,
title = {Projective and external saturation problem for posets},
author = {Dömötör Pálvölgyi and Balázs Patkós},
journal= {arXiv preprint arXiv:2306.10387},
year = {2023}
}