The Asaeda-Haagerup fusion categories

TL;DR

This paper introduces a new, symmetric construction of the Asaeda-Haagerup subfactor using a Z/4Z x Z/2Z analogue, enabling comprehensive analysis and classification of its properties and extensions.

Contribution

It provides a new symmetric construction of the Asaeda-Haagerup subfactor via a Z/4Z x Z/2Z analogue, facilitating its analysis and classification.

Findings

Constructed a new subfactor S as a Z/4Z x Z/2Z analogue of the Haagerup subfactor.

Showed the even parts of the Asaeda-Haagerup subfactor are higher Morita equivalent to an orbifold quotient of S.

Enabled calculation of the Drinfel'd center and classification of extensions for the Asaeda-Haagerup fusion categories.

Abstract

The classification of subfactors of small index revealed several new subfactors. The first subfactor above index 4, the Haagerup subfactor, is increasingly well understood and appears to lie in a (discrete) infinite family of subfactors where the Z/3Z symmetry is replaced by other finite Abelian groups. The goal of this paper is to give a similarly good description of the Asaeda-Haagerup subfactor which emerged from our study of its Brauer-Picard groupoid. More specifically, we construct a new subfactor S which is a Z/4Z x Z/2Z analogue of the Haagerup subfactor and we show that the even parts of the Asaeda-Haagerup subfactor are higher Morita equivalent to an orbifold quotient of S. This gives a new construction of the Asaeda-Haagerup subfactor which is much more symmetric and easier to work with than the original construction. As a consequence, we can settle many open questions about the Asaeda-Haagerup subfactor: calculating its Drinfel'd center, classifying all extensions of the Asaeda-Haagerup fusion categories, finding the full higher Morita equivalence class of the Asaeda-Haagerup fusion categories, and finding intermediate subfactor lattices for subfactors coming from the Asaeda-Haagerup categories. The details of the applications will be given in subsequent papers.