Isometric dilations and Beurling quotient modules

Abstract

In \cite{Dan-Guo}, the authors provided a characterization of all sequences of doubly commuting pure contractions that have the sequence $\textbf{M}_z,$ the sequence of the multiplication by the coordinate functions on the vector-valued Hardy space $H^2_\mathcal E(\mathbb {D}_2^{(\infty)})$ over the Hilbert's multidisk $\mathbb D_2^{(\infty)},$ as their minimal isometric dilation for some Hilbert space $\mathcal E$. In this article, we remove the hypothesis of doubly commutativity and characterize all sequences of commuting contractions that are unitarily equivalent to $(P_{\mathcal Q}M_{z_i}|_{\mathcal Q})_{i\geq 1}$ for some quotient module $\mathcal Q$ of $H^2_\mathcal E(\mathbb D_2^{(\infty)})$. We further characterize those sequences for which $\mathcal Q$ is a Beurling quotient module. This generalizes Theorem 3.2 from \cite{BKD} to a sequence of commuting contractions.