Fluents and Actions
In the event calculus, fluents are reified. This means that statements are not formalized as predicates but as functions. A separate predicate is used to tell which fluents hold at a given time point. For example, means that the box is on the table at time ; in this formula, is a predicate while is a function.
Actions are also represented as terms. The effects of actions are given using the predicates and . In particular, means that, if the action represented by the term is executed at time, then the fluent will be true after . The predicate has a similar meaning, with the only difference being that will be false and not true after .
Read more about this topic: Event Calculus
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