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arXiv · 2507.08353

The Induced Saturation Number for $\mathcal{V}_3$ is Linear

James Brownlie·Sean Jaffe
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Abstract

Given a poset $\mathcal{P}$, a family $\mathcal{F}$ of elements in the Boolean lattice is said to be $\mathcal{P}$-saturated if $\mathcal{F}$ does not contain an induced copy $\mathcal P$, but every proper superset of $\mathcal{F}$ contains one. The minimum size of a $\mathcal P$-saturated family in the $n$-dimensional Boolean lattice is denoted by $sat^*(n,\mathcal{P})$.\par In this paper, we consider the poset $\mathcal V_3$ (the four element poset with one minimal element and three incomparable maximal elements) and show that $sat^*(n,\mathcal{V}_3)\geq \frac{n}{2}$. This represents the first linear lower bound for $sat^*(n,\mathcal{V}_3)$, improving upon the previously best-known bound of $2\sqrt{n}$. Our result establishes that $sat^*(n,\mathcal{V}_3) = \Theta(n)$.

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James Brownlie, Sean Jaffe. 2025-07-11. The Induced Saturation Number for $\mathcal{V}_3$ is Linear. https://arxiv.org/abs/2507.08353

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