\cdbproperty{ImplicitIndex}{}

Indicates that the object carries implicit indices, e.g.~for objects
representing matrices or vectors. Such objects will not be moved
through each other, i.e.~they are mutually noncommuting.
\begin{screen}{1,2,3}
{M,A}::ImplicitIndex;
M A;
@prodsort!(%);
M A;
\end{screen}
Without the \subsprop{ImplicitIndex} property, \subscommand{prodsort}
would have freely moved the objects through each other.

For more information on how to use matrices and vectors with implicit
indices, see \subscommand{expand}.

\cdbseealgo{expand}
