English

Four generators of an equivalence lattice with consecutive block counts

Rings and Algebras 2024-10-22 v1

Abstract

The block count of an equivalence μ\mu\in Equ(A)(A) is the number blnum(μ)(\mu) of blocks of (the partition corresponding to) μ\mu. We say that X={μ1,μ2,μ3,μ4}X=\{\mu_1,\mu_2,\mu_3,\mu_4\} is a four-element generating set of Equ(A)(A) with consecutive block counts if XX generates Equ(A)(A) and blnum(μi+1)(\mu_{i+1}) = blnum(μ1)+i(\mu_{1})+i for i{1,2,3}i\in\{1,2,3\}. We prove that if the number of elements of a finite set AA is six or at least eight, then Equ(A)(A) has a four-element generating set with consecutive block counts. Also, we present a historical remark on the connection between equivalence lattices and quasiorder lattices.

Keywords

Cite

@article{arxiv.2410.15328,
  title  = {Four generators of an equivalence lattice with consecutive block counts},
  author = {Gábor Czédli},
  journal= {arXiv preprint arXiv:2410.15328},
  year   = {2024}
}

Comments

12 pages, 4 figures