Editing Process calculus (section)

=== Sequential composition ===

Sometimes interactions must be temporally ordered. For example, it might be desirable to specify algorithms such as: ''first receive some data on <math>\mathit{x}</math> and then send that data on <math>\mathit{y}</math>''.  ''Sequential composition'' can be used for such purposes. It is well known from other models of computation. In process calculi, the sequentialisation operator is usually integrated with input or output, or both. For example, the process <math>x(v)\cdot P</math> will wait for an input on <math>\mathit{x}</math>. Only when this input has occurred will the process <math>\mathit{P}</math> be activated, with the received data through <math>\mathit{x}</math> substituted for identifier <math>\mathit{v}</math>.