t;Note that this issue arises for most common properties of, and relations
&gt; &gt;among, classes; e.g., transitivity, reflexivity, subclass, etc.
&gt; 
&gt; I agree.  Does having implication for the similar axioms that define these 
&gt; relations seem right to you?

I'm in two minds about disjointness, since both its weaker and stronger
forms are useful.  However, it does seem to me that when anyone other
than Pat Hayes sez that a relation is symmetric, say, they are saying
something more than that it ju