Strong completeness of Lp-type vector lattices

Abstract

Let E be a Dedekind complete Riesz space with weak unit e, equipped with a conditional expectation operator T. We prove that the spaces Lp(T), with their natural vector-valued norms, are strongly complete, extending the p=2 case of Kuo, Kalauch, and Watson. This resolves a question that has remained open for several years. We begin by studying a general type of convergence and its unbounded modification, unifying and generalizing order, norm, and absolute weak convergence while providing simpler proofs. As an application, we consider vector-valued norms and their unbounded variants, generalizing strong convergence in Lp-spaces and convergence in probability. This framework establishes the completeness of Lp(T) and of the universal completion E^{u}, reinforcing the uo-completeness of universally complete vector lattices. Finally we apply our main theorem to obtain a new result in ergodicity for conditional preserving systems.