OFFSET
0,3
COMMENTS
In a poset, a mail is a nonempty set of elements of the poset having a common lower bound. A chainmail is a poset in which every mail has a join.
This sequence can be directly calculated from A374073 by using an Euler transform (also known as Riddell's formula).
LINKS
J. F. Du Plessis, Z. Janelidze, and B. A. Wessels, A Primer on Chainmails: Structures for Point-free Connectivity, arXiv:2406.16923 [math.GM], 2024.
FORMULA
Euler transform of A374073.
CROSSREFS
Cf. A374073 (connected).
KEYWORD
nonn,hard,more
AUTHOR
Jean F. du Plessis, Jun 30 2024
STATUS
approved