Spectral finiteness, quantum norm continuity and classical points

Abstract

We prove various notions of uniform continuity for compact-quantum-group representations on Hilbert or Banach spaces equivalent to having finite spectrum, i.e. finitely many isotypic components. This generalizes the classical analogue for compact-group representations on Banach spaces, and relies in part on Riemann-Lebesgue-type decay properties for Fourier coefficients of elements in minimal tensor products with compact-quantum-group function algebras.

v3 makes a number of technical alterations (statement and proof of Theorem 0.3, Lemma 1.8), minor changes and reference updates; 13 pages + references