rators are summarized as follows:
<BR>&nbsp;
<TABLE BORDER >
<TR>
<TD ALIGN=CENTER VALIGN=TOP><B>Operator&nbsp;</B></TD>

<TD ALIGN=CENTER VALIGN=TOP><B>Type&nbsp;</B></TD>

<TD ALIGN=LEFT VALIGN=TOP><B>Description&nbsp;</B></TD>
</TR>

<TR>
<TD ALIGN=CENTER VALIGN=TOP>+&nbsp;</TD>

<TD ALIGN=CENTER VALIGN=TOP>Additive&nbsp;</TD>

<TD ALIGN=LEFT VALIGN=TOP>addition&nbsp;</TD>
</TR>

<TR>
<TD ALIGN=CENTER VALIGN=TOP>-&nbsp;</TD>

<TD ALIGN=LEFT VALIGN=TOP></TD>

<TD ALIGN=LEFT VALIGN=TOP>subtraction&nbsp;</T