[SCL] Some questions for SCL and RDF

[John F. Sowa]

Tanel,

That situation arises with many languages
that we would like to bring under the
CL banner:

 > The machinery used in these semantics is
 > explicit encoding. RDF and OWL formulas are
 > not translated "directly" to FOL. Instead,
 > a number of predicates like type, class,
 > relation, symmetric etc are used.

Some languages have a clear separation between
logic and ontology (which we are trying to
keep clear in the CL family).  But many
languages incorporate a great deal of
ontology into the basic syntax and operators.

An example of a mixture of logic and ontology
is the common BNF notation for grammar rules:

  S -> NP VP

This could be mapped to a Horn-clause statement
with the addition of a LeftOf relation that says
the constituent designated as NP is to the left
of the constituent designated as VP.

 > These predicates are associated with a finite
 > list of axioms.

I suggest that we distinguish "pure CL" langauges
or subset languages from languages that include
additional ontology.  If you have a language L
whose syntax or operators incorporate some additional
ontology, then any theory stated in L would map
to a theory in a pure CL langauge that would
include additional axioms that define those
predicates.

John Sowa