Expanding a model theoretically `tame’ structure in a way that it stays `tame’ has been a theme in the recent years. In the first part of this talk, we present a history of work done in that frame. Then we focus on the case of expansions of o-minimal structures by a unary predicate. There is a dividing line according to whether the predicate is dense or discrete
- Séminaire Géométrie et théorie des modèles