definition-t vs. definition-k

Robert MacGregor <>
Message-id: <>
Subject: definition-t vs. definition-k
Date: Mon, 23 Jul 90 14:47:23 PDT
From: Robert MacGregor <>
> KIF would allow a query about what John thinks the definition of
> bachelor is.  It is my understanding that the terminological
> languages would not allow such statements.

False (at least in LOOM).  Concepts are objects, and one of the slots of
a concept contains its definition (actually, because we NORMALIZE
definitions, the situation is a bit more complex than this, i.e., you
can ask for either the source definition or the normalized definition).
> As I see it, definition-t is subsumed by definition-k, so the
> only reason to make a distinction is if there is a more
> efficient way of compiling definition-ts.  From my own work as a
> RL implementor, I know that certain optimizations can be made
> when one assumes that the terminological component is frozen (in
> other words, closed world assumption over definitions).

The optimizations performed on the role hierarchies in LOOM make closed
world assumptions that get revised whenever the terminological
component is updated.  So we get the benefits of optimization without
the necessity for "freezing" the terminological component.

Eliminable definitions:  I believe that I am agreement with Dave's suggestion,
modulo the necessity for accounting for primitive definitions.

Cheers, Bob