A Model Management Imperative: Being Graphical Is Not Sufficient, You Have to Be Categorical

Graph-based modeling is both common in and fundamental for Model Driven Engineering (MDE). The paper argues that several important model management (MMt) scenarios require an essential extension of graphical models. We show that different versions of model merge and sync, including many-to-many correspondences between models, can be treated in a uniform, compact and well-defined mathematical way if we specify graphical models as directed graphs with associative arrow composition and identity loops, that is, as categories.