A unifying approach to connections for multi-level modeling

Capturing relationships between concepts in a domain is as important as capturing the concepts themselves. Modeling languages reflect this by providing connections with rich semantics, such as associations and links, thus providing a key advantage over approaches that support relationships with simple references only. While connections for two-level modeling (e.g. in the UML) have enjoyed a stable design for a considerable time, the same cannot be said for connections in multi-level modeling languages. As interest in multi-level modeling grows, it is important to provide a comprehensive design for connections that not only adheres to multi-level principles such as level-agnosticism and explicit level organization, but also supports deep characterization, i.e., the ability to specify level content beyond one level boundary. In this paper we propose a unifying conceptual model for connections whose expressiveness and scalability does not come at the cost of concept proliferation.