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Sigma KEE - domain
Provides a computationally and heuristically convenient mechanism for declaring the argument types of a given relation. The formula (
?REL ?INT ?CLASS) means that the ?INT'th element of each tuple in the relation ?REL must be an instance of ?CLASS. Specifying argument types is very helpful in maintaining ontologies. Representation systems can use these specifications to classify terms and check integrity constraints. If the restriction on the argument type of a
is not captured by a
already defined in the ontology, one can specify a
compositionally with the functions
Properties or qualities as distinguished from any particular embodiment of the properties/qualities in a physical medium. Instances of Abstract can be said to exist in the same sense as mathematical objects such as sets and relations, but they cannot exist at a particular place and time without some physical encoding or embodiment.
The universal class of individuals. This is the root node of the ontology.
The class of
s whose properties can be inherited downward in the class hierarchy via the
is a sentence-forming
. Each tuple in the
is a finite, ordered sequence of objects. The fact that a particular tuple is an element of a
is denoted by '(*predicate* arg_1 arg_2 .. arg_n)', where the arg_i are the objects so related. In the case of
s, the fact can be read as `arg_1 is *predicate* arg_2' or `a *predicate* of arg_1 is arg_2'.
of relations. There are two kinds of
s both denote sets of ordered n-tuples. The difference between these two
es is that
s cover formula-forming operators, while
s cover term-forming operators.
s that require exactly three arguments.
s relate three items. The two
Belongs to Class
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