English

Generating naturally labeled posets through matrix extensions, order ideals and automorphism groups

Combinatorics 2026-05-19 v2

Abstract

We propose a matrix approach for generating naturally labeled posets by representing each poset PP on the set [n][n] as a Boolean poset matrix AA. This algebraic representation enables a systematic handling of partial orderings through matrix extensions AvA^v. We show that AvA^v defines a valid poset matrix if and only if the Boolean vector vBnv\in\mathbb B^n represents an order ideal of the poset PP associated to AA, equivalently satisfying the fixed-point equation vA=vvA=v. Based on this characterization, we develop a sieve algorithm that generates all admissible extension vectors efficiently. Furthermore, we explore the twin-class decomposition of AA, which partitions the elements of PP according to identical down- and up-sets. This structure provides an algebraic foundation for Burnside-type enumeration for Birkhoff's question on counting nonisomorphic posets on [n][n] through the automorphism group Aut(A){\rm Aut}(A). Finally, we present an algorithmic generation scheme for the posets based on the topological growth of their distributive lattices, offering a new approach to constructive enumeration of poset families.

Keywords

Cite

@article{arxiv.2512.17749,
  title  = {Generating naturally labeled posets through matrix extensions, order ideals and automorphism groups},
  author = {Gi-Sang Cheon and Samuele Giraudo and Gukwon Kwon and Hojoon Lee},
  journal= {arXiv preprint arXiv:2512.17749},
  year   = {2026}
}

Comments

28 pages

R2 v1 2026-07-01T08:33:47.243Z