IMI : The necklace poset is a symmetric chain order

Preprint Series

This is a series in pure, applied, and computational mathematics by members of the Interdisciplinary Mathematics Institute.

IMI members may submit preprints by email request to:

Diana Diaz
Email: ddiaz@mailbox.sc.edu

Preprint Series by Year

2007:09
Let $N _ n$ denote the quotient poset of the Boolean lattice, $B _ n$, under the relation equivalence under rotation. Griggs, Killian, and Savage proved that $N _ p$ is a symmetric chain order for prime p. In this paper, we settle the question of whether this poset is a symmetric chain order for all n by providing an algorithm that produces a symmetric chain decompostion (or SCD). We accomplish this by modifying bracketing from Greene and Kleitman. This allows us to take appropriate “middles” of certain chains from the Greene-Kleitman SCD for $B _ n$. We also prove additional properties of the resulting SCD and show that this settles a related conjecture.