# The 2A-Majorana representations of the Harada-Norton group

Clara Franchi, Alexander A. Ivanov, Mario Mainardis

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5 Citazioni (Scopus)

## Abstract

We show that all $2A$-Majorana representations of the Harada-Norton group $F_5$ have the same shape. If ${\mathcal R}$ is such a representation, we determine, using the theory of association schemes, the dimension and the irreducible constituents of the linear span $U$ of the Majorana axes. Finally, we prove that, if ${\mathcal R}$ is based on the (unique) embedding of $F_5$ in the Monster, $U$ is closed under the algebra product.
Lingua originale English 175-187 13 Ars Mathematica Contemporanea 11 Pubblicato - 2015

## Keywords

• ASSOCIATION SCHEMES
• MAJORANA REPRESENTATIONS
• MONSTER ALGEBRA