Infinitesimal approach of almost-automorphic functions (Q687285)

Introducing the concept of ideal elements of ``several levels'', the author gives a compact topological characterization of almost-automorphic functions. This new characterization appears to be equivalent to a geometric one: the existence of a relatively dense group of ``pointwise periods''. The author claims that a more significant result is a lowering of the complexity in characterizations and proofs. However, this ``lowering'' is obtained only after introducing an additional ``adequate language'' and a conservative extension of ZFC.