Abstract
Solutions of the moving medium reduced wave equation for a supersonic stream in the presence of a cascade have been derived by Goldstein, Braun and Adamczyk who used an extension of the Wiener-Hopf technique as previously applied to electromagnetic and subsonic wave motion. This note shows that their solutions, which are in complex variable form and involve an arbitrary small parameter ∊>0, satisfy a uniqueness theorem. The regularity of the solulions for ∊→0 is discussed.