Dimension Preserving Contractions and a Finite List of 3-Irreducible Posets

摘要

This paper introduces new poset operations-dimension-preserving contractions. These contractions are used to change a poset into a similar, but simpler, poset with the same dimension. In particular, they can be used to turn the well-known infinite list of 3-irreducible posets into seventeen 3-irreducible, noncontractible posets (up to duality).