If ℘ is a poset and every antichain is finite, and if the length of the well-founded poset of antichains is less than ω21, then ℘ is the union of countably many chains. We also compute the length of the poset of antichains in the product of two ordinals, αxβ.
- AMS subject classifications (1980): 03E05 Combinatorial set theory, 03E10 Ordinal and cardinal numbers, 06A10 Partial order
ASJC Scopus subject areas
- Algebra and Number Theory
- Geometry and Topology
- Computational Theory and Mathematics