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.
