English

Free skew Boolean intersection algebras and set partitions

Rings and Algebras 2024-11-12 v1 Combinatorics

Abstract

We show that atoms of the nn-generated free left-handed skew Boolean intersection algebra are in a bijective correspondence with pointed partitions of non-empty subsets of {1,2,,n}\{1,2,\dots, n\}. Furthermore, under the canonical inclusion into the kk-generated free algebra, where knk\geq n, an atom of the nn-generated free algebra decomposes into an orthogonal join of atoms of the kk-generated free algebra in an agreement with the containment relation on the respective partitions. As a consequence of these results, we describe the structure of finite free left-handed skew Boolean intersection algebras and express several their combinatorial characteristics in terms of Bell numbers and Stirling numbers of the second kind. We also look at the infinite case. For countably many generators, our constructions lead to the `partition analogue' of the Cantor tree whose boundary is the `partition variant' of the Cantor set.

Keywords

Cite

@article{arxiv.1602.01789,
  title  = {Free skew Boolean intersection algebras and set partitions},
  author = {Ganna Kudryavtseva},
  journal= {arXiv preprint arXiv:1602.01789},
  year   = {2024}
}
R2 v1 2026-06-22T12:43:46.641Z