The Motzkin subproduct system
Valeriano Aiello, Simone Del Vecchio, Stefano Rossi
TL;DR
The paper constructs a Motzkin subproduct system by employing Motzkin algebras and their Jones–Wenzl idempotents, extending the Temperley–Lieb subproduct systems to a broader planar-algebraic setting. It provides a concrete realization of the associated Toeplitz and Cuntz–Pimsner C*-algebras as universal C*-algebras defined by generators and relations, and analyzes their representation theory via a gauge action and conditional expectations. Key results include faithfulness of Motzkin-pair representations for suitable parameters, the standard subproduct-system structure generated by $g_k$, and the identification of $\mathcal{O}_P$ as the compact-quotient of $\mathcal{T}_P$, with universality and irreducibility results guiding the representation theory. The work connects noncommutative polynomial ideals, planar algebras, and C*-algebraic invariants, offering a pathway to new symmetries and potential connections to quantum group actions and Thompson-like groups.
Abstract
We introduce a subproduct system of finite-dimensional Hilbert spaces by using the Motzkin planar algebra and its Motzkin Jones-Wenzl idempotents, which generalizes the Temperley-Lieb subproduct system of Habbestad and Neshveyev. We provide a description of the corresponding Toeplitz and Cuntz-Pimsner C$^*$-algebras as universal C$^*$-algebras, defined in terms of generators and relations, and we highlight properties of their representation theory.
