John, I have a question about one of your comments: (01)
>
>A class is defined as a pair (t,s), where t is a monadic relation called
the type,
>and s is the set of everything for which t is true.
> (02)
It seems as though in this definition, if the relation "t" alone defines
a class, then every class must be defined by both necessary and sufficient
conditions ("the set of **everything** for which t is true").
But In many ontologies I have seen many classes are described by only
necessary conditions. In this case, satisfying the predicate is not enough
to be a member of the class, though being a member of the class necessarily
means that one satisfies the necessary conditions. (03)
Does this mean that the typical "class" in an OWL ontology is not a
"Class" in this formalism? (04)
Comments? (05)
Pat (06)
Patrick Cassidy
MICRA Inc.
cassidy@xxxxxxxxx
1-908-561-3416 (07)
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