% formatted on 970304 by morris
\documentstyle{article}
\setcounter{page}{4}
\textheight 9.5in
\textwidth 5.75in
\voffset -1in
\hoffset -0.5in
\begin{document}
%\documentstyle[12pt]{llncs}

%\begin{document}
\title{ Factorization of Hankel Matrices}

%\author{D. Boley\inst{1}, F. Luk\inst{2} and D.Vandevoorde\inst{3}}
%
%\institute{Department of Mathematics, RMIT \\ 
%124 Latrobe St, Melbourne, Victoria 3000, Australia 
%\and 
%Department of Computer Science, Rensselaer Polytechnic Institute \\
%Troy, NY 12180, U.S.A.
%}
\author{D. Boley \\ Department of Mathematics, RMIT \\
124 Latrobe St, Melbourne, Victoria 3000, Australia
\and
F. Luk \\ Department of Computer Science, Rensselaer Polytechnic Institute\\
Troy, NY 12180, U.S.A.
\and
D.Vandevoorde
}
\date{}

\maketitle
Hankel matrices arise during the analysis of signals from linear dynamic
systems.  To carry out this analysis, it is necessary to factor a Hankel
matrix constructed from the signal into the product LDU where U is the
transpose of L, and D is diagonal.  In one factorization, L is a lower
triangular matrix, and we show that an earlier algorithm by the authors
for this case, originally designed for real Hankel matrices, can almost
be carried out for the complex case.  In another factorization, L is a
Vandermonde matrix, and recent work by Vandevoorde has given an efficient
way to construct this factorization.  This leads to a natural way to find
a nearby Hankel matrix of lower rank.
\end{document}

