This clause provides additional comments. Aliases are name substitutions that override precedence rules, i.e., treated as an atom, and not just as a macro expansion. Each name declares a distinct object. Type declares all the events that are output by the operation together with their destinations, the receiving actor classes.
Occurrence declares event occurrences and collections of event occurrences.
Order defines the constraints on the order of events output by the operation. The condition that must be met for the postcondition to be guaranteed. It is a boolean expression written in OCL, standing for a predicate. The condition that will be met after the execution of the operation. It is a boolean expression written in OCL, standing for a predicate.