Loading problem…
Status
On this page
Status
Topics
Problem 497
How many antichains in are there? That is, how many families of subsets of are there such that, if is such a family and , then ?
Source: erdosproblems.com/497
- Combinatorics
Status
Solved, AnsweredAn accepted solution exists. Settled in another form, for example when its parts resolve differently or the question is open-ended.
The site labels the problem SOLVED (LEAN), crediting Kleitman [Kl69]; the Lean artifact behind the qualifier is described under Formalization. The accepted claim is the number of antichains is 2 to the (1+o(1)) middle layer.