Interactions and Roles

The diagram below indicates, within the S*Metamodel, the scope of ideas mostly closely associated with Interactions (Functional Interactions):

As discussed in System , by "Interaction" we mean that the System Components are exchanging Input-Outputs, which typically are Energy, Force, Material, or Information, resulting in change of State of the System Components.

The behaviors of the System Components within the Interaction are referred to as the Functional Roles (or just Roles) of the interaction. There must be at least two such Roles for any Interaction, but there can be more, as Interactions may involve many Roles. These Roles are "pure behavior", in the sense that they are fully defined by their input-output relationships, parameterized by their States.