![UML sequence diagrams overview of graphical notation - lifeline, message, execution specification, interaction use, etc. UML sequence diagrams overview of graphical notation - lifeline, message, execution specification, interaction use, etc.](https://www.uml-diagrams.org/notation/sequence-ref.png)
UML sequence diagrams overview of graphical notation - lifeline, message, execution specification, interaction use, etc.
![UML sequence diagrams overview of graphical notation - lifeline, message, execution specification, interaction use, etc. UML sequence diagrams overview of graphical notation - lifeline, message, execution specification, interaction use, etc.](https://www.uml-diagrams.org/notation/sequence-execution-spec.png)
UML sequence diagrams overview of graphical notation - lifeline, message, execution specification, interaction use, etc.
![UML sequence diagrams overview of graphical notation - lifeline, message, execution specification, interaction use, etc. UML sequence diagrams overview of graphical notation - lifeline, message, execution specification, interaction use, etc.](https://www.uml-diagrams.org/notation/sequence-ref-params.png)
UML sequence diagrams overview of graphical notation - lifeline, message, execution specification, interaction use, etc.
![UML sequence diagram combined fragment is an interaction fragment which defines a combination (expression) of interaction fragments. UML sequence diagram combined fragment is an interaction fragment which defines a combination (expression) of interaction fragments.](https://www.uml-diagrams.org/notation/sequence-operator-alt.png)
UML sequence diagram combined fragment is an interaction fragment which defines a combination (expression) of interaction fragments.
![UML sequence diagrams overview of graphical notation - lifeline, message, execution specification, interaction use, etc. UML sequence diagrams overview of graphical notation - lifeline, message, execution specification, interaction use, etc.](https://www.uml-diagrams.org/sequence-diagrams/sequence-diagram-overview.png)