&gt; 
&gt; &gt; 3. Ordered collections - Tuples, classifications of them are
&gt; &gt; known as relations. These are timeless, and indeed one way
&gt; &gt; of defining tuples derives them from sets.
&gt; &gt; 
&gt; &gt; Regards  
&gt; &gt;       Matthew
&gt; &gt; ===========================================
&gt; &gt; Matthew West
&gt; &gt; Operations &amp; Asset Management
&gt; &gt; Shell Services International
&gt; &gt; H3229, Shell Centre, London, SE1 7NA, UK.
&gt; &gt; Tel: +44 207 934 4490 Fax: 7929 
&gt