Spaces of rapidly oscillating functions
For various function spaces of the form gU or U+gV, U and V e.g. almost periodic functions AP, (bounded) uniformly continuous functions BUC, UC, g(t) = exp(it^2), their properties are discussed, especially a Loomis type condition (Delta) which has been essential in getting such properties : A satisfies (Delta) if for any loclly integrable f : J -> X with all differences f(.+h) - f(.) in A for all positive h implies f(.) - (1/h) integral from 0 to h f(.+s)ds in A (J = [0,infty) or R, X any Banach space).