esentation of the resource model, intended for machine interpretation. The notation is textual. The state vector must com- prise the information of the resource model graph and any additional informa- tion from the rules and property sections. To translate a resource model graph into a state vector is an example of specification refinement. The state model syntax is an optional section that defines graphical symbols for entities and relations of the resource model, and also defines drawing rules. This syntax allows service states and object states to be visualized graphically in other information elements, e.g. in state diagrams (see the example discussed in Sect. 1.6.4). Remark is a temporary part used to record questions, assumptions and review remarks, which frequently arise during the development of a resource model. It is a very valuable section while the resource model is developed. 7.3.2 The Resource Model Graph This graph is built by entities that symbolize resources, relations between enti- ties and properties. Entities are defined by resource names (textstrings). Resource names have initial upper-case letters. A resource name must be unique only within a given resource model. Given a particular concept, the question often arises if that concept should be regarded as a resource, a resource relation or a property. That is always the user's choice, within the restrictions defined by AML. These are: A property is part of a property list that is associated with a resource. A resource can have any number of properties. Properties cannot be shared between resources. Direct relations between properties are not allowed. A resource can have any number of relations to other resources. There cannot be any relations between resource relations. Relations are different kinds of arrows, according to Fig. 7.1. The name of a relation is sometimes implied by the graphical symbol (as isA, isP, err, arr, exclOr 7.3 Resource Model Notation and or) or recommended by AML (as acr and symb). To minimize confusion, all relations 