Abstract

In their paper from 1981, Milner and Sauer conjectured that for any poset $$\langle P,\le\rangle$$ , if $$cf(P,\le)=\lambda>cf(\lambda)=\kappa$$ , then P must contain an antichain of size κ. We prove that for λ > cf(λ) = κ, if there exists a cardinal μ < λ such that cov(λ, μ, κ, 2) = λ, then any poset of cofinality λ contains λ κ antichains of size κ. The hypothesis of our theorem is very weak and is a consequence of many well-known axioms such as GCH, SSH and PFA. The consistency of the negation of this hypothesis is unknown.

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