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Noncommutative Minkowski integral inequality and a unitary categorification criterion for fusion rings

Junhwi Lim

TL;DR

The paper develops a noncommutative Minkowski-type integral inequality for commuting squares of tracial von Neumann algebras, supported by a generalized Hölder inequality and a central variant. It then demonstrates how this inequality yields a practical criterion for testing whether graphs can realize a commuting square and, consequently, whether a given fusion or based ring admits a unitary categorification. Applying the criterion to large datasets of fusion rings, the authors exclude a substantial fraction and provide insights into which rings remain candidates under existing Drinfeld-type and related criteria. Overall, the work builds a bridge between operator-algebraic inequalities and the realizability of unitary fusion and based categories, offering concrete tools for classification and exclusion in categorical representation theory.

Abstract

We prove a noncommutative analogue of Minkowski's integral inequality for commuting squares of tracial von Neumann algebras. The inequality implies a necessary condition for a quadruple of graphs to be realized as inclusion graphs of a commuting square of multi-matrix algebras. As a corollary, we obtain a unitary categorification criterion for based rings, in particular, fusion rings.

Noncommutative Minkowski integral inequality and a unitary categorification criterion for fusion rings

TL;DR

The paper develops a noncommutative Minkowski-type integral inequality for commuting squares of tracial von Neumann algebras, supported by a generalized Hölder inequality and a central variant. It then demonstrates how this inequality yields a practical criterion for testing whether graphs can realize a commuting square and, consequently, whether a given fusion or based ring admits a unitary categorification. Applying the criterion to large datasets of fusion rings, the authors exclude a substantial fraction and provide insights into which rings remain candidates under existing Drinfeld-type and related criteria. Overall, the work builds a bridge between operator-algebraic inequalities and the realizability of unitary fusion and based categories, offering concrete tools for classification and exclusion in categorical representation theory.

Abstract

We prove a noncommutative analogue of Minkowski's integral inequality for commuting squares of tracial von Neumann algebras. The inequality implies a necessary condition for a quadruple of graphs to be realized as inclusion graphs of a commuting square of multi-matrix algebras. As a corollary, we obtain a unitary categorification criterion for based rings, in particular, fusion rings.
Paper Structure (8 sections, 13 theorems, 38 equations)

This paper contains 8 sections, 13 theorems, 38 equations.

Key Result

Theorem A

Let $(\mathcal{M},\mathop{\mathrm{tr}}\nolimits)$ be a tracial von Neumann algebra, $\mathcal{N}\subset \mathcal{L},\mathcal{K}\subset \mathcal{M}$ be von Neumann subalgebras and $x\in \mathcal{M}$ be a positive element satisfying the following: Then for $1\le p<\infty$ we have

Theorems & Definitions (28)

  • Theorem A
  • Theorem B
  • Corollary C
  • Theorem 2.1: NCLp
  • Definition 2.2
  • Remark 2.3
  • Lemma 2.4: Reduced Hölder inequality
  • proof
  • Proposition 2.5
  • proof
  • ...and 18 more