m is too close to the boundary of
                the stability domain;
          = 7:  if a singular matrix was encountered during the
                computation of the solution matrix X.

</PRE>
<A name="Method"><B><FONT SIZE="+1">Method</FONT></B></A>
<PRE>
  The routine uses a variant of the method of deflating subspaces
  proposed by van Dooren [1]. See also [2], [3], [4].
  It is assumed that E is nonsingular, the triple (E,A,B) is
  strongly stabilizable and detectable (see [3]); if, in addition,

 