t;
&gt; MW: This is about data modelling issues, not logic issues, and if it
&gt; doesn't make sense, can be safely ignored (unless you design
&gt; databases).

Ok.

&gt; &gt; &gt;  - lambda calculus is used for defining constraints.
&gt; &gt;
&gt; &gt; There are two major varieties of lambda calculus -- typed and
&gt; &gt; untyped -- and I don't see that either is needed, or even usable,
&gt; &gt; for ontology.
&gt;
&gt; MW: I may misunderstand what Lambda Calculus is about...

You do.  Or you did.  :-)

&