Hi, Oleg<br>Thanks for your time and your brilliant code. I think this problem is solved.<br>Best wishes to you<br><br>Regards<br>Bin<br><br><div class="gmail_quote">On Wed, Nov 9, 2011 at 2:05 PM,  <span dir="ltr">&lt;<a href="mailto:oleg@okmij.org">oleg@okmij.org</a>&gt;</span> wrote:<br>

<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
    p2num :: Dep a b</blockquote></div><br>