Process composition; Service composition
In computer science, composition is the act or mechanism to combine simple components to build more complicated ones. Composition exists at different levels. For example, one can think of the usual composition of functions in mathematics, i.e., the result of the composed function is passed to the composing one via a parameter. If one has to functions f and g, these can be combined into a new function h = f.g, i.e., h(x) = f(g(x)). Another level of abstraction is the level of activities. Here all kinds of process modeling languages can be used to compose activities into processes (e.g., Petri nets, BPMN, etc.). Typical composition operators are sequential composition, parallel composition, etc. Process composition is related to business process management, workflow management, etc. Yet another level of abstraction is provided by services, i.e., more complex services can be composed from simpler ones even when they do not...