The realization concept is specialized to (optionally) define the classifiers that realize the contract offered by a component in terms of its provided and required interfaces.

The component forms an abstraction from these various

classifiers.

An element import identifies an element in another package, and allows the element to be referenced using its name without a qualifier.

A relationship from an extending use case to an extended use case that specifies how and when the behavior defined in the extending use case can be inserted into the behavior defined in the extended use case.

A generalization is a taxonomic relationship between a more general classifier and a more specific classifier. Each instance of the specific classifier is also an indirect instance of the general classifier. Thus, the specific classifier inherits the features of the more general classifier.

A generalization relates a specific classifier to a more general classifier, and is owned by the specific classifier.

An include relationship defines that a use case contains the behavior defined in another use case.

An information flow specifies that one or more information items circulates from its sources to its targets.

Informationflows require some kind of information channel for transmitting information items from the source to the destination. An information channel is represented in various ways depending on the nature of its sources and targets. It may berepresented by connectors, links, associations, or even dependencies.

For example, if the source and destination are partsin some composite structure such as a collaboration, then the information channel is likely to be represented by aconnector between them. Or, if the source and target are objects (which are a kind of instance specification), they may berepresented by a link that joins the two, and so on.

An interface realization is a specialized realization relationship between a classifier and an interface. This relationship signifies that the realizing classifier conforms to the contract specified by the interface.

A package import is a relationship that allows the use of unqualified names to refer to package members from other namespaces.

A package merge defines how the contents of one package are extended by the contents of another package.

Protocol state machines can be redefined into more specific protocol state machines, or into behavioral state machines.

Protocol conformance declares that the specific protocol state machine specifies a protocol that conforms to the general state machine one, or that the specific behavioral state machine abide by the protocol of the general protocol state machine.

A template binding represents a relationship between a templateable element and a template. A template binding specifies the substitutions of actual parameters for the formal parameters of the template.