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Main Authors: Kirkpatrick, Caoilainn, Mahmoud, Amelie el, Ormsby, Kyle, Osorno, Angélica M., Schandelmeier-Lynch, Dale, Shahar, Riley, Yi, Lixing, Young, Avery, Zhu, Saron
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2508.20786
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author Kirkpatrick, Caoilainn
Mahmoud, Amelie el
Ormsby, Kyle
Osorno, Angélica M.
Schandelmeier-Lynch, Dale
Shahar, Riley
Yi, Lixing
Young, Avery
Zhu, Saron
author_facet Kirkpatrick, Caoilainn
Mahmoud, Amelie el
Ormsby, Kyle
Osorno, Angélica M.
Schandelmeier-Lynch, Dale
Shahar, Riley
Yi, Lixing
Young, Avery
Zhu, Saron
contents Given a finite commutative monoid $M$, we show that submonoids of $M\times [n]$ - where $[n] = \{0,1,\ldots,n\}$ is equipped with the max operation $\vee$ - may be enumerated via the transfer matrix method. When $M$ is also idempotent, we show that there are finitely many integers $λ$ and rational numbers $b_λ$ (only depending on $M$) such that the number of submonoids of $M\times [n]$ is $\sum_λb_λλ^n$. This answers a question of Knuth regarding ternary (and higher order) max-closed relations, and has applications to the enumeration of saturated transfer systems in equivariant infinite loop space theory.
format Preprint
id arxiv_https___arxiv_org_abs_2508_20786
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Enumerating submonoids of finite commutative monoids
Kirkpatrick, Caoilainn
Mahmoud, Amelie el
Ormsby, Kyle
Osorno, Angélica M.
Schandelmeier-Lynch, Dale
Shahar, Riley
Yi, Lixing
Young, Avery
Zhu, Saron
Combinatorics
Algebraic Topology
05A15, 20M10, 55P91
Given a finite commutative monoid $M$, we show that submonoids of $M\times [n]$ - where $[n] = \{0,1,\ldots,n\}$ is equipped with the max operation $\vee$ - may be enumerated via the transfer matrix method. When $M$ is also idempotent, we show that there are finitely many integers $λ$ and rational numbers $b_λ$ (only depending on $M$) such that the number of submonoids of $M\times [n]$ is $\sum_λb_λλ^n$. This answers a question of Knuth regarding ternary (and higher order) max-closed relations, and has applications to the enumeration of saturated transfer systems in equivariant infinite loop space theory.
title Enumerating submonoids of finite commutative monoids
topic Combinatorics
Algebraic Topology
05A15, 20M10, 55P91
url https://arxiv.org/abs/2508.20786