is x in R^n or else f : R^n -&gt; R, is not affected one liitle bit
&gt; &gt; by the syntactic expression, whatever its structure, that is used
&gt; &gt; to refer to it.  And if anybody thinks to make ontological capital
&gt; &gt; off the abuse of notation, or the poetic license, that permits us
&gt; &gt; to write "f(x, y, z)" instead of "f(&lt;x, y, z&gt;)", or vice versa,
&gt; &gt; then that person has another think coming.  The arity of the
&gt; &gt; relation is the same either way.
&gt; &gt;
&gt; &gt; J