Re: TMRM: isa/sub - irreflexive relation vs. reflexive relation

On Wed, Oct 05, 2011 at 11:05:41AM +0200, Lars Heuer wrote:

> ...................................................... Why is the
> "isa" relation irreflexive by definition and the "sub" relation
> reflexive by definition (c.f. TMRM 5 a) and 5 b)?

From a modelling perspective, the way I would find "isa" most useful
is to express a relationship between an individual and a group. To say
that

   lheuer isa lheuer

would undermine that idea. It would make lheuer an individual, and
also a class (on its own). One can still assert it explicitly, but
according to TMRM it would not appear intrinsically.

For "sub" the reflexitivity is simply a convenience, not to the least
for programming.

\rho