Interaction between units is governed by contracts, which are administered by a purpose manager. The capability of the unit is defined by the processes it can do, and the contracts define the conditions under which each process may be instantiated. Obligations and objectives in terms of the contracts are managed by the purpose manager in response to messages between units. A process manager instantiates processes to fulfill these obligations. Workflow between actors is managed within the unit by the process manager, which allocates each process step to an appropriate actor. Communication between units is effected by a message manager, which translates the internal representation to that specified in the contract, and selects the appropriate communication medium and address. Contracts, standards, process definitions and entities are all kinds of business object, which in this design are fractal. Each manager is able to select suitable objects according to its needs.