Categories of Predicates

Next, we categorize the different types of Predicates that we have identified.

Special Predicates

True Predicate

This Predicate is always evaluated to true.

False Predicate

This Predicate is always evaluated to false.

Unary Predicates

Is Predicate

evaluated to true if the current Predicable is an Entity and has the same identity has the one defined by the Predicate's attribute.

InfluencedBy Predicate

This Predicate is evaluated to true if the current Predicable is influenced by the Influence identified by the Predicate's attribute.

Possess Predicate

This Predicate is evaluated to true if the Predicable is in possession of the Entity identified by the Predicate's attribute.

CanPerform Predicate

This Predicate is evaluated to true if the Predicable can perform the Action identified by the Predicate's attribute.

Binary Predicates

Binary Predicates are more complex Predicates which attributes are composed by a couple of values, named first and second argument respectively. Next, we detail binary Predicates.

LesserThan Predicate

First argument: Property name

Second argument: Threshold value

This Predicate is evaluated to true if the current Predicable has a Property named like the first argument and this Property has a value that is lesser than the value given by the second argument.

GreaterThan Predicate

First argument: Property name

Second argument: Threshold value

This Predicate is evaluated to true if the current Predicable has a Property named like the first argument and this Property has a value that is greater than the value given by the second argument.

EqualsTo Predicate

First argument: Property name

Second argument: Threshold value

This Predicate is evaluated to true if the current Predicable has a Property named like the first argument and this Property has a value that is equals to the value given by the second argument.

KnowsAbout Predicate

First argument: Entity identifier

Second argument: Level of knowledge

This Predicate is evaluated to true if the current Predicable knows about the Entity identified by the first argument with a level given by the second argument.

RelatesTo Predicate

First argument: Entity identifier

Second argument: Type of relation

This Predicate is evaluated to true if the current Predicable is related to the Entity identified by the first argument by a link given by the second argument.