Our view of computation is still evolving. The
for specific computational phenomena that are emerging encompass three aspects: specification and programming languages for describing computations, mathematical structures for modelling computations, and logics for reasoning about properties of computations. To make sense of this complexity, and also to compare and/or relate different concrete theories,
have been built. These metatheories are used for the study, formalisation, specification, prototyping, and testing of concrete theories.