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Sigma KEE - altitude
that is used to state the
and another point that is below the
(often this other point will be sea level). Note that this
can be used to specify, for example, the height of geographic features, e.g. mountains, the altitude of aircraft, and the orbit of satellites around the Earth.
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
partial valued relation
just in case it is not a
, i.e. just in case assigning values to every argument position except the last one does not necessarily mean that there is a value assignment for the last argument position. Note that, if a
is both a
, then it is a partial function.
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.
single valued relation
just in case an assignment of values to every argument position except the last one determines at most one assignment for the last argument position. Note that not all
s that require exactly three arguments.
s relate three items. The two
Belongs to Class
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