On the realization of a class of $\text{SL}(2,\mathbb{Z})$ representations

Let p<q be odd primes and \rho_{1} and \rho_{2} be irreducible representations of \text{SL}(2,\mathbb{Z}_{p}) and  \text{SL}(2,\mathbb{Z}_{q}) of dimensions \frac{p+1}{2} and \frac{q+1}{2} , respectively. We show that if \rho_{1}\oplus\rho_{2} can be realized as a modular representation associate...

Full description

Saved in:
Bibliographic Details
Published inJournal of noncommutative geometry Vol. 18; no. 4; pp. 1521 - 1542
Main Author Yu, Zhiqiang
Format Journal Article
LanguageEnglish
Japanese
Published 25.06.2024
Online AccessGet full text

Cover

Loading…
More Information
Summary:Let p<q be odd primes and \rho_{1} and \rho_{2} be irreducible representations of \text{SL}(2,\mathbb{Z}_{p}) and  \text{SL}(2,\mathbb{Z}_{q}) of dimensions \frac{p+1}{2} and \frac{q+1}{2} , respectively. We show that if \rho_{1}\oplus\rho_{2} can be realized as a modular representation associated with a modular fusion category \mathcal{C} , then q-p=4 . Moreover, if \mathcal{C} contains a non-trivial étale algebra, then \mathcal{C}\boxtimes\mathcal{C}(\mathbb{Z}_{p},\eta)\cong\mathcal{Z}(\mathcal{A}) as a braided fusion category, where  \mathcal{A} is a near-group fusion category of type (\mathbb{Z}_{p},p) , which gives a partial answer to the conjecture of D. Evans and T. Gannon. We also show that there exists a non-trivial \mathbb{Z}_{2} -extension of \mathcal{A} that contains simple objects of Frobenius–Perron dimension \frac{\sqrt{p}+\sqrt{q}}{2} .
ISSN:1661-6952
1661-6960
DOI:10.4171/jncg/578