Operations on system states and their components.
These operations are used to define the state transitions of the system, as well as to formulate and prove the correctness of the system. A few of these operations may not actually be used to define the state transiitons of the system, but they are similar to ones that are used for that, and thus it makes sense to group them together.
Additional operations that are only used to formulate and prove correctness are in operations-additional.