This statement is a rule, which defines an identity on a concept. It is syntactic sugar for specifying a set of relations that identify atoms in a specific concept. For example, if relations pi and rho determine an atom of concept T uniquely, you can write:
As the IDENT statement defines a rule, it can be in the same places as any other RULE.
where:
<label> is the name of the rule. It can be a single word or a string (enclosed by double brackets). It is followed by a colon (:) to distinguish the label from the concept that follows.
<Concept> is the name of the Concept for atoms of which the rule specifies an identity
Between brackets are terms whose source concept must be <Concept>. This is enforced by the type system.
translates into the following rule:
Note that
in case everyeis both univalent and total, e<>e~ equals e;e~, and the rule is equivalent to:
in case every e is univalent but not total, you should use the IDENT statement (or the rule that it implements), because that also works when an e is not populated.