<TT>datatype term =<BR>
          &nbsp;&nbsp;&nbsp;&nbsp;FD of FD.fd<BR>
          &nbsp;&nbsp;| `&nbsp;&nbsp;of int<BR>
          &nbsp;&nbsp;| `+ of term * term<BR>
          &nbsp;&nbsp;| `- of term * term<BR>
          &nbsp;&nbsp;| `* of term * term</TT>
    </DT>
    <DD>
      <P>This datatype is used to post arithmetic constraints.
      </P>
      <UL>
        <LI><TT>FD <I>x</I></TT> injects the finite domain
            variable <I>x</I> into a term.
        <LI><TT>` <I>i</I></TT> injects a int