Immediately algebraically closed fields

Abstract

We consider two overlapping classes of fields, IAC and VAC, which are defined using valuation theory but which do not involve a distinguished valuation. Rather, each class is defined by a condition that quantifies over all possible valuations on the field. In his thesis, Hong asked whether these two classes are equal. In this paper, we give an example that negatively answers Hong’s question. We also explore several situations in which the equivalence does hold with an additional assumption, including the case where every $K^{\prime }\equiv K$ is IAC.