We consider that every system is dynamic and, therefore, subject to change. We restrict ourselves to reactive systems; i.e., their change of state is always a reaction to an external action.
In our case the actions are produced by the action of a protocol which is executed by a user as its agent.
The protocols operate on one or more system objects, objects that, at the same time, change state by the action of the protocol.
The system state is represented by the states of their objects.
The facts are determined by the execution of protocols over time.
An object may have information which does not depend on its states and, generally, will have information which does depend on its states.
The data associated with a state may vary over time in successive state changes or, on the contrary, it may be that data is not affected by any state change.
All data is associated with an object or with a state of that object. In this latter case, the state is that in which the data was perceived for the first time.
The data is valid as long as nothing to the contrary is stated in the system.
Data destruction is not allowed. In the case where the data is no longer valid, the system must record this as a fact.
The system distinguishes the valid data from the invalid.
Data modification is not allowed unless it proceeds from the execution of an agreed protocol. In this case, the original data becomes automatically invalid.
Español
