Excerpted from DomainDrivenDesignBook

Problem: When there is a lot of interaction between subdomains in separate Modules, either many references will have to be created between Modules, which defeats much of the value of the partitioning, or the interaction will have to be made indirect, which makes the model obscure.

Solution: Identify the most fundamental concepts in the model and factor them into distinct classes, abstract classes, or interfaces. Design this abstract model so that it expresses most of the interaction between significant components. Place this abstract overall model in its own Module, while the specialized, detailed implementation classes are left in their own Modules defined by subdomain.

AbstractCore is mentioned on: PluggableComponentFramework | MessagesByTopic