  We discuss the challenges of motivating, constructing, and quantizing a
canonically normalized inflationary perturbation in spatially curved universes.
We show that this has historically proved challenging due to the interaction of
nonadiabaticity with spatial curvature. We construct a novel curvature
perturbation that is canonically normalized in the sense of its equation of
motion and is unique up to a single scalar parameter. With this construction it
becomes possible to set initial conditions invariant under canonical
transformations, overcoming known ambiguities in the literature. This corrected
quantization has potentially observational consequences via modifications to
the primordial power spectrum at large angular scales, as well as theoretical
implications for quantization procedures in curved cosmologies filled with a
scalar field.
