LIGN="CENTER" NOWRAP><A NAME="1.2.7"></A><IMG
 WIDTH="56" HEIGHT="12" BORDER="0"
 SRC="img67.png"
 ALT="\begin{displaymath}
u = Wv
\end{displaymath}"></TD>
<TD WIDTH=10 ALIGN="RIGHT">
(2.11)</TD></TR>
</TABLE>
<BR CLEAR="ALL"></DIV><P></P>
and  this transformation is  <EM>useful</EM> if the  matrix <IMG
 WIDTH="16" HEIGHT="12" ALIGN="BOTTOM" BORDER="0"
 SRC="img68.png"
 ALT="$W$"> has fewer
rows than columns.

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