\begin{table}%t1
%\centering
\par
\caption{Eigenvalue relationships defining the characteristic morphologies. The
         $\lambda$-conditions describe objects with intensity higher than their
		 local background as clusters, filaments or walls. For voids we would have to reverse the
	     sign of the eigenvalues.
\label{tab:morph}}
\begin{tabular} {ccl}
\hline
\hline
Structure & $\lambda$ ratios & $\quad$ $\lambda$ constraints \\
\hline
%\ &&\\
Blob     &  $\lambda_1 \simeq \lambda_2 \simeq \lambda_3$ & $\lambda_3 <0  ;~~ \lambda_2 <0  ;~~ \lambda_1 <0 $  \\
%\ &&\\
Filament     &  $\lambda_1 \simeq \lambda_2 \gg    \lambda_3$ & $\lambda_3 <0  ;~~ \lambda_2 <0  $  \\
%\ &&\\
Sheet    &  $\lambda_1 \gg    \lambda_2 \simeq \lambda_3$ & $\lambda_3 <0 $    \\
\hline
\end{tabular}
\end{table}