Coherent configurations and Frobenius structures

Fuente: arXiv
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Main Authors: Jenča, Gejza, Jenčová, Anna, Lachman, Dominik
Format: Preprint
Published: 2025
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author Jenča, Gejza
Jenčová, Anna
Lachman, Dominik
author_facet Jenča, Gejza
Jenčová, Anna
Lachman, Dominik
contents We prove that coherent configurations can be represented as modules over Frobenius structures in the category of real nonnegative matrices. We generalize the notion of admissible morphism from association schemes to coherent configurations. We show that the Frobenius structure associated to a coherent configuration can be modified to become a dagger Frobenius structure, and use this to connect the coherent configurations to groupoids and $H^*$-algebras. We examine the properties of the dagger Frobenius structure with respect to admissible morphisms. We introduce the matrix $O$ obtained as the composition of comultiplication and multiplication of the dagger Frobenius structure and prove that we may obtain the valencies of colors, and thus recover the original coherent configuration, as an eigenvector of $O$. In the last part of the paper, we examine the spectrum of $O$ and apply it to generalize the Lagrange theorem from groups to association schemes.
format Preprint
id arxiv_https___arxiv_org_abs_2507_21774
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Coherent configurations and Frobenius structures
Jenča, Gejza
Jenčová, Anna
Lachman, Dominik
Combinatorics
Rings and Algebras
05E30, 16W30
We prove that coherent configurations can be represented as modules over Frobenius structures in the category of real nonnegative matrices. We generalize the notion of admissible morphism from association schemes to coherent configurations. We show that the Frobenius structure associated to a coherent configuration can be modified to become a dagger Frobenius structure, and use this to connect the coherent configurations to groupoids and $H^*$-algebras. We examine the properties of the dagger Frobenius structure with respect to admissible morphisms. We introduce the matrix $O$ obtained as the composition of comultiplication and multiplication of the dagger Frobenius structure and prove that we may obtain the valencies of colors, and thus recover the original coherent configuration, as an eigenvector of $O$. In the last part of the paper, we examine the spectrum of $O$ and apply it to generalize the Lagrange theorem from groups to association schemes.
title Coherent configurations and Frobenius structures
topic Combinatorics
Rings and Algebras
05E30, 16W30
url https://arxiv.org/abs/2507.21774