Relational Structures (RS) are ubiquitous. RS appear in many forms and situations, like database models, all kinds of spreadsheet usage, state machines or flow diagrams, directory trees, all kinds of ontologies and taxonomies etc. Figure (simple) shows a very simple relation in x-matrix form.
When Relational Structures (RS) get harder understanding helps. As the number of relation elements grows, as in figure (hard), the RS becomes harder to ‘deal with’. For this purpose a deeper understanding of the relation might be quite helpful. So, we look for ways how such an understanding can be provided.
Modelling provides understanding. In understanding, abstraction plays a central role as described in part one ‘Modelling for Understanding’. Performing an abstracting mapping from original to model is what we call modelling. This mapping is our object of study in part two ‘Understanding of Modelling’. Notice that part one is informal whereas part two – the actual modelling theory – is rigorously founded in order theory, graph theory, formal concept analysis, finite model theory etc.