## Involve: A Journal of Mathematics

• Involve
• Volume 12, Number 8 (2019), 1379-1397.

### Split Grothendieck rings of rooted trees and skew shapes via monoid representations

#### Abstract

We study commutative ring structures on the integral span of rooted trees and $n$-dimensional skew shapes. The multiplication in these rings arises from the smash product operation on monoid representations in pointed sets. We interpret these as Grothendieck rings of indecomposable monoid representations over $F1$ — the “field” of one element. We also study the base-change homomorphism from $〈t〉$-modules to $k[t]$-modules for a field $k$ containing all roots of unity, and interpret the result in terms of Jordan decompositions of adjacency matrices of certain graphs.

#### Article information

Source
Involve, Volume 12, Number 8 (2019), 1379-1397.

Dates
Revised: 18 September 2019
Accepted: 20 September 2019
First available in Project Euclid: 12 December 2019

https://projecteuclid.org/euclid.involve/1576119633

Digital Object Identifier
doi:10.2140/involve.2019.12.1379

Mathematical Reviews number (MathSciNet)
MR4041271

Zentralblatt MATH identifier
07162472

#### Citation

Beers, David; Szczesny, Matt. Split Grothendieck rings of rooted trees and skew shapes via monoid representations. Involve 12 (2019), no. 8, 1379--1397. doi:10.2140/involve.2019.12.1379. https://projecteuclid.org/euclid.involve/1576119633

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