On weakly o-minimal non-valuational expansions of ordered groups

Let M = 〈M,<,+, . . .〉 be a weakly o-minimal expansion of an ordered group. This paper has two parts. In the rst part, we introduce the notion of M having no external limits and use it to prove that a large collection of non-valuational structures M do not admit de nable Skolem functions. In the second part, we provide an alternative characterization of the canonical o-minimal completion from [11] and employ it to produce new examples of non-valuational structures.