Re: clarifying clarifying ontologies (Fritz Lehmann)
Date: Tue, 8 Aug 95 15:57:43 CDT
From: (Fritz Lehmann)
Message-id: <>
Subject: Re: clarifying clarifying ontologies
Cc: doug@CSI.UOTTAWA.CA,, hovy@ISI.EDU,,
Precedence: bulk
     John Sowa mentioned:
---begin quote---
_Representing Time in Natural Language_, MIT Press, 1995.  In it, she gives
a nice classification based on distinctions, combinations, and constraints
(see my last note endorsing Ken Forbus' point).  She makes three basic
 1. A _hole_ is a description of an event that allows information to flow
 2. A _filter_ restricts the flow.
 3. A _plug_ blocks the flow.
Based on these three distinctions (with all + and - combinations of them)
she derives her _aspectual cube_ with eight kinds of verbs or aspects of
verbs at the corners.  (A lattice would be an equivalent way of displaying
the combinations.) 
---end quote---

     This example, along with Sowa's recent upper ontology, Parker-Rhodes'
base-domains, specialized KL-ONE "BOXES", and the "conceptual scales"
of Ganter & Wille, all illustrate the important and generally unduly-
neglected _product_structure_ of a taxonomy.  Much of the large-scale
structure of conceptual hierarchies can be analyzed into a lattice or
other poset which is a direct-product (or my fret-product where there
are symmetries) of independent factor-hierarchies.  Each factor is a
"conceptual dimension" of the main hierarchy.  In ter Meulen's example
given above by Sowa, 1., 2. and 3., are each single-link chains, the
direct-product of which is an upended cube.  In other cases the factor
relations in a hierarchy are not so simple.  We need to see more of this
"factor analysis" of ontologies, whether they are general linguistic ones
or highly specialized ones.

                          Yours truly,   Fritz Lehmann
GRANDAI Software, 4282 Sandburg Way, Irvine, CA 92715, U.S.A.
Tel:(714)-856-0671               email: