SUO: Re: W3C approves RDF and OWL
Adam,
Every relational noun in English -- such as parent, employee,
or client -- designates two things: a relational pattern and
a class of entities that fit the pattern.
A simple way to generate the corresponding representation in
FOL is to use declarations such as those that I proposed for
CLCE. Following is an example:
Declare object as noun from SQL("SELECT ID FROM OBJECTS"),
shape as functional noun (x1 shape of x2)
from SQL("SELECT SHAPE, ID FROM OBJECTS"),
color as functional noun (x1 color of x2)
from SQL("SELECT COLOR, ID FROM OBJECTS"),
supporter as noun (x1 supporter of x2)
with relation(support)
from SQL("SELECT * FROM SUPPORTS"),
supportee as noun (x2 supportee of x1)
with relation(support);
The first line of this declaration introduces "object" as
a _categorial noun_, which is represented by either a type
label in typed logic or a monadic predicate in an untyped
logic.
The next 4 lines define "color" and "shape" as functional
nouns (a special case of relational nouns), which can be
represented as either a dyadic relation or as a monadic
function, depending on which kind of notation you prefer.
But in addition to the relation, they also create type labels
or monadic predicates for "color" and "shape" when they are
used as categorial nouns without the preposition "of".
The last 5 lines define "supporter" and "supportee" as
relational nouns, which both map to the same dyadic relation
named "support", which is mapped to an SQL table named
"supports". Note that the arguments of "supportee" are
mapped to the relation "support" in the reverse order of
the argument mapping of "supporter".
In addition to the mappings to the relation named support,
the two nouns "supporter" and "supportee" also correpond to
type labels or monadic relations for the classes of objects
that happen to be supporters or supportees.
All of this is implicit knowledge that is familiar to every
English speaker, and all the information needed for the
CLCE translator to generate a representation in FOL can be
derived from the above declaration. In this case, each
relational noun maps to a dyadic relation and to a monadic
relation (or type label). The monadic relation can always
be derived from the dyadic relation by a simple mapping:
supportee(x) = (Ey)support(y,x)
supporter(x) = (Ey)support(x,y)
For further discussion of this example, see Section 2 of
the CLCE specification:
http://www.jfsowa.com/clce/specs.htm
John