We attempt at a logical characterization of reasoning about normality based on the intuition that a normal situation is represented by a stable set of default assumptions. Within the context of preferential consequence relations we shall define a normality operator B and study its logical properties. Finally we shall focus on the AGM-like postulates for the normality expansion, contraction and ...

A number is normal to the base r if, in its expansion to that base, all possible digit strings of length t are equally frequent for each t. While it is generally believed that many familiar irrational constants are normal, normality has only been proven for numbers expressly invented for the purpose of proving their normality. In this study we give an overview of the main results to date. We th...