\cdbproperty{Metric}{{\it signature={\sf integer}}}

Labels the object as a symmetric tensor, and optionally gives it the
indicated signature through the {\tt signature} parameter.
\begin{screen}{1,2,3}
g_{m n}::Metric(signature=1).
g_{m n} A^{n p};
@eliminate_metric!(%);
A_{m}^{p};
\end{screen}
Objects declared as \subsprop{Metrics} can be used to automatically
raise or lower indices using the
\subscommand{eliminate\_metric} command.

\cdbseealgo{eliminate_metric}
