;;; Mode: Lisp; Package: ocml

;;; The Open University

(in-package "OCML")

(in-ontology akt-support-ontology)

;;;A very simple top-level. We define something called THING, which 
;;;is the top-level concept in the ontology.  We then distinguish two basic 
;;;types of 'things': TANGIBLE-THING, something that has some physicality,
;;;and INTANGIBLE-THING, something which has not. We use a very open definition 
;;;of being tangible: obviusly a physical object is tangible, but also a sub-atomic
;;;particle is tangible, even if some of them are very tricky (you do not see them)
;;;you only see the trace they leave behind.  Also a piece of software will be
;;;considered a tangible thing, it is something that you can see on a floppy disk.
;;;In contrast an algorithm will be an intangible, although the file that contains
;;;its implementation will be a tangible thing.

;;;This is a stop-gap top level. Over the course of teh project we may want to extend this 
;;;and link to existing top levels (SUO, HPKB, CYC, Sowa, Guarino, etc.)


(def-class THING ()
  "This is the top-level concept in the AKT reference ontology"
  )


(def-class INTANGIBLE-THING (thing)
  "This comes from HPKB upper level.
   The collection of things that are not physical -- are not made 
   of, or encoded in, matter. Every Collection is an Intangible (even if its
   instances are tangible), and so are some Individuals. 
   Caution: do not confuse `tangibility' with `perceivability' -- humans can perceive
   light even though it's intangible--at least in a sense.")

(def-class TANGIBLE-THING (thing)
  "Something which is not intangible")

(def-axiom TANGIBLE-AND-INTANGIBLE-THINGS-ARE-DISJOINT
  (subclass-partition thing (set-of Tangible-Thing  Intangible-thing)))

(def-class QUANTITY (Intangible-thing)
  ((has-unit-of-measure :type unit-of-measure)
   (has-magnitude :type number)))

(def-class UNIT-OF-MEASURE (Intangible-thing)
  "Any kind of unit of measure, metre, dollar, kilogram, etc..")