The preceding discussion has shown that multiple ResourceSpecifications can share common characteristics. <br/>This can be more efficiently represented using the concept of a ResourceSpecType, as shown in the Figure below:<br/>The ResourceSpecificationTypeCategorizes relationship defines the ResourceSpecificationTypes that are used to classify and catalog different ResourceSpecifications. <br/>The InvolvedResourceSpecTypes association defines the set of ResourceSpecifications that are involved with, or related to, each other in order to build a particular type of ResourceSpecification.<br/><i>Note that in principle, ResourceSpecType could be subclassed, so that the subclasses of ResourceSpecType could be used to categorize different subclasses of ResourceSpecification. This is not recommended, as the ResourceSpecType object is used solely to help categorize objects. The only reason a ResourceSpecType should be subclassed is if that subclass adds additional semantics (in the form of attributes, methods, relationships, and/or constraints).</i><br/>