TY - JOUR
T1 - Quotients of A2 ∗ T2
AU - Izumi, Masaki
AU - Morrison, Scott
AU - Penneys, David
N1 - Publisher Copyright:
© Canadian Mathematical Society 2016.
PY - 2016/10
Y1 - 2016/10
N2 - Westudy unitary quotients of the free product unitary pivotal category A2 ∗ T2. Weshow that such quotients are parametrized by an integer n ≥ 1 and an 2n-th root of unity ω. We show that for n = 1,2,3, there is exactly one quotient and ω = 1. For 4 ≤ n ≤ 10, we show that there are no such quotients. Our methods also apply to quotients of T2 ∗ T2, where we have a similar result. The essence of our method is a consistency check on jellyfish relations. While we only treat the specific cases of A2 ∗ T2 and T2 ∗ T2, we anticipate that our technique can be extended to a general method for proving the nonexistence of planar algebras with a specified principal graph. During the preparation of this manuscript, we learnt of Liu's independent result on composites of A3 and A4 subfactor planar algebras (arxiv:1308.5691). In 1994, Bisch-Haagerup showed that the principal graph of a composite of A3 and A4 must fit into a certain family, and Liu has classified all such subfactor planar algebras. We explain the connection between the quotient categories and the corresponding composite subfactor planar algebras. As a corollary of Liu's result, there are no such quotient categories for n ≥ 4.
AB - Westudy unitary quotients of the free product unitary pivotal category A2 ∗ T2. Weshow that such quotients are parametrized by an integer n ≥ 1 and an 2n-th root of unity ω. We show that for n = 1,2,3, there is exactly one quotient and ω = 1. For 4 ≤ n ≤ 10, we show that there are no such quotients. Our methods also apply to quotients of T2 ∗ T2, where we have a similar result. The essence of our method is a consistency check on jellyfish relations. While we only treat the specific cases of A2 ∗ T2 and T2 ∗ T2, we anticipate that our technique can be extended to a general method for proving the nonexistence of planar algebras with a specified principal graph. During the preparation of this manuscript, we learnt of Liu's independent result on composites of A3 and A4 subfactor planar algebras (arxiv:1308.5691). In 1994, Bisch-Haagerup showed that the principal graph of a composite of A3 and A4 must fit into a certain family, and Liu has classified all such subfactor planar algebras. We explain the connection between the quotient categories and the corresponding composite subfactor planar algebras. As a corollary of Liu's result, there are no such quotient categories for n ≥ 4.
KW - Free product
KW - Intermediate subfactor
KW - Pivotal category
KW - Quotient
KW - Subfactor
UR - http://www.scopus.com/inward/record.url?scp=84983604689&partnerID=8YFLogxK
U2 - 10.4153/CJM-2015-017-4
DO - 10.4153/CJM-2015-017-4
M3 - Article
SN - 0008-414X
VL - 68
SP - 999
EP - 1022
JO - Canadian Journal of Mathematics
JF - Canadian Journal of Mathematics
IS - 5
ER -