Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Frobenius algebra objects in Temperley-Lieb categories at roots of unity

Grant, Joseph and Pugh, Mathew ORCID: https://orcid.org/0000-0001-9045-3713 2025. Frobenius algebra objects in Temperley-Lieb categories at roots of unity. Quantum Topology 10.1017/S0017089525100876

[thumbnail of frobenius-algebra-objects-in-temperley-lieb-categories-at-roots-of-unity.pdf]
Preview
PDF - Published Version
Available under License Creative Commons Attribution Non-commercial No Derivatives.

Download (894kB) | Preview

Abstract

We give a new definition of a Frobenius structure on an algebra object in a monoidal category, generalising Frobenius algebras in the category of vector spaces. Our definition allows Frobenius forms valued in objects other than the unit object, and can be seen as a categorical version of Frobenius extensions of the second kind. When the monoidal category is pivotal we define a Nakayama morphism for the Frobenius structure and explain what it means for this morphism to have finite order. Our main example is a well-studied algebra object in the (additive and idempotent completion of the) Temperley-Lieb category at a root of unity. We show that this algebra has a Frobenius structure and that its Nakayama morphism has order 2. As a consequence, we obtain information about Nakayama morphisms of preprojective algebras of Dynkin type, considered as algebras over the semisimple algebras on their vertices.

Item Type: Article
Date Type: Published Online
Status: In Press
Schools: Schools > Mathematics
Subjects: Q Science > QA Mathematics
Publisher: EMS Press
ISSN: 1663-487X
Date of First Compliant Deposit: 27 November 2025
Date of Acceptance: 27 November 2025
Last Modified: 27 Apr 2026 09:53
URI: https://orca.cardiff.ac.uk/id/eprint/176998

Actions (repository staff only)

Edit Item Edit Item

Downloads

Downloads per month over past year

View more statistics