http://popups.lib.uliege.be/1373-5411/index.php?id=2389 The possible unknown behaviour of a reactive system may not be fully understood but it may be modelled in an information system. The relationship between a system and its model can be constructed through a series of stages showing the correlation between arrows in the system and in the model. Such a diagram is formal where the system and the model are 2-cell categories and the mappings between the system and the model are adjunctions. Such mappings can be built up using basic arrow constructions or given in a more abstract form in terms of freeness and co-freeness. The adequacy of a model as a representation of a natural system is discussed in terms of mapping properties such as reflection, isomorphism and adjoint equivalence. The circumstances for the model being anticipatory are considered. Full text issues Volume 16 The Universe, the Nothing that is! fr Thu, 08 Aug 2024 09:27:26 +0200 Thu, 10 Oct 2024 10:34:41 +0200 http://popups.lib.uliege.be/1373-5411/index.php?id=2389 0