Hsu–Logan–Shahriari chain partition conjecture for normalized matching posets

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Let QQ be a finite graded poset with levels A0,…,AnA_0,\ldots,A_n. It is rank-symmetric if ∣Ai∣=∣An−i∣|A_i|=|A_{n-i}|, unimodal if its level sizes increase and then decrease, and a normalized matching poset if it has the LYM property: every antichain S⊂QS\subset Q satisfies

∑i=0n∣S∩Ai∣∣Ai∣≤1.\sum_{i=0}^{n}\frac{|S\cap A_i|}{|A_i|}\leq 1.

Let ww be the width of QQ, and set l=⌊∣Q∣/w⌋l=\lfloor |Q|/w\rfloor.

Hsu–Logan–Shahriari conjecture. If QQ is a rank-symmetric, unimodal normalized matching poset of width ww, then QQ can be partitioned into ww chains, each chain in the partition having size ll or l+1l+1.

This extends Füredi's conjecture from the Boolean lattice to rank-symmetric, unimodal normalized matching posets. The source states that this conjecture is open.

References

Primary source

István Tomon, “Forbidden induced subposets in the grid”, arXiv:1705.09551 (2017).

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