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Related papers: New hyperfinite subfactors with infinite depth

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Subfactors of the hyperfinite II$_1$ factor with ''exotic'' properties can be constructed from nondegenerate commuting squares of multi-matrix algebras. We show that the subfactor planar algebra of these commuting square subfactors…

Operator Algebras · Mathematics 2024-10-22 Dietmar Bisch , Julio Cáceres

We construct numerous continuous families of irreducible subfactors of the hyperfinite II$_1$ factor, which are non-isomorphic, but have all the same standard invariant. In particular, we obtain 1-parameter families of irreducible,…

Operator Algebras · Mathematics 2007-05-23 Dietmar Bisch , Remus Nicoara , Sorin Popa

We prove existence of subfactors of finite depth of the hyperfinite II_1 factor with indices (5+sqrt{13})/2= 4.302... and (5+sqrt{17})/2=4.561.... The existence of the former was announced by the second named author in 1993 and that of the…

Operator Algebras · Mathematics 2009-10-31 M. Asaeda , U. Haagerup

Discrete, unimodular inclusions of factors $(N\subseteq M, E)$ with $N$ of type $\rm{II}_{1}$ have a natural notion of standard invariant, generalizing the finite index case. When the unitary tensor category of $N$-$N$ bimodules generated…

Operator Algebras · Mathematics 2025-10-15 Corey Jones , Emily McGovern

An inclusion of II$_1$ factors $N \subset M$ with finite Jones index gives rise to a powerful set of invariants that can be approached successfully in a number of different ways. We describe Jones' pictorial description of the standard…

Operator Algebras · Mathematics 2007-05-23 Dietmar Bisch

Subfactor standard invariants encode quantum symmetries. The small index subfactor classification program has been a rich source of interesting quantum symmetries. We give the complete classification of subfactor standard invariants to…

Operator Algebras · Mathematics 2015-09-02 Narjess Afzaly , Scott Morrison , David Penneys

We consider noncommuting pairs P,Q of intermediate subfactors of an irreducible, finite-index inclusion N in M of II_1 factors such that P and Q are supertransitive with Jones index less than 4 over N. We show that up to isomorphism of the…

Operator Algebras · Mathematics 2007-05-23 Pinhas Grossman

We give the classification of subfactor planar algebras at index exactly 5. All the examples arise as standard invariants of subgroup subfactors. Some of the requisite uniqueness results come from work of Izumi in preparation. The…

Operator Algebras · Mathematics 2015-09-03 Masaki Izumi , Scott Morrison , David Penneys , Emily Peters , Noah Snyder

We construct irreducible hyperfinite subfactors of index 6 with a prescribed fundamental group from a large family containing all countable and many uncountable subgroups of R_+. We also prove that there are unclassifiably many irreducible…

Operator Algebras · Mathematics 2016-07-25 Arnaud Brothier , Stefaan Vaes

To any complex Hadamard matrix H one associates a spin model commuting square, and therefore a hyperfinite subfactor. The standard invariant of this subfactor captures certain "group-like" symmetries of H. To gain some insight, we compute…

Operator Algebras · Mathematics 2007-05-23 Wes Camp , Remus Nicoara

Subfactor theory provides a tool to analyze and construct extensions of Quantum Field Theories, once the latter are formulated as local nets of von Neumann algebras. We generalize some of the results of [LR95] to the case of extensions with…

Operator Algebras · Mathematics 2018-04-11 Simone Del Vecchio , Luca Giorgetti

Progress on classifying small index subfactors has revealed an almost empty landscape. In this paper we give some evidence that this desert continues up to index 3+\sqrt{5}. There are two known quantum-group subfactors with index in this…

Operator Algebras · Mathematics 2015-09-03 Scott Morrison , Emily Peters

If $G$ is a countable, discrete group generated by two finite subgroups $H$ and $K$ and $P$ is a II$_1$ factor with an outer G-action, one can construct the group-type subfactor $P^H \subset P \rtimes K$ introduced in \cite{BH}. This…

Operator Algebras · Mathematics 2009-03-26 Dietmar Bisch , Paramita Das , Shamindra Kumar Ghosh

If $N \subset P,Q \subset M$ are type II_1 factors with $N' \cap M = C id$ and $[M:N]$ finite we show that restrictions on the standard invariants of the elementary inclusions $N \subset P$, $N \subset Q$, $P \subset M$ and $Q \subset M$…

Operator Algebras · Mathematics 2007-05-23 Pinhas Grossman , Vaughan F. R. Jones

In this series of papers we show that there are exactly ten subfactors, other than $A_\infty$ subfactors, of index between 4 and 5. Previously this classification was known up to index $3+\sqrt{3}$. In the first paper we give an analogue of…

Operator Algebras · Mathematics 2015-09-03 Scott Morrison , Noah Snyder

Jones and Penneys showed that a finite depth subfactor planar algebra embeds in the bipartite graph planar algebra of its principal graph, via a Markov towers of algebras approach. We relate several equivalent perspectives on the notion of…

Operator Algebras · Mathematics 2018-10-17 Desmond Coles , Peter Huston , David Penneys , Srivatsa Srinivas

Using a m\'elange of techniques at the rich intersection of deformation/rigidity theory, finite index subfactor theory, and geometric group theory, we prove the existence of a continuum of property (T) factors that are pairwise non-stably…

Operator Algebras · Mathematics 2025-11-11 Ionut Chifan , Junhwi Lim

A subfactor is an inclusion $N \subset M$ of von Neumann algebras with trivial centers. The simplest example comes from the fixed points of a group action $M^G \subset M$, and subfactors can be thought of as fixed points of more general…

Operator Algebras · Mathematics 2015-09-03 Vaughan F. R. Jones , Scott Morrison , Noah Snyder

We show that any semi-direct sum $L$ of Lie algebras with Levi factor $S$ must be perfect if the representation associated with it does not possess a copy of the trivial representation. As a consequence, all invariant functions of $L$ must…

Differential Geometry · Mathematics 2023-01-04 J C Ndogmo

We summarize the known obstructions to subfactors with principal graphs which begin with a triple point. One is based on Jones's quadratic tangles techniques, although we apply it in a novel way. The other two are based on connections…

Operator Algebras · Mathematics 2012-03-13 Scott Morrison , David Penneys , Emily Peters , Noah Snyder
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