\cdbproperty{Matrix}{}

Declares an object to have two implicit indices, thus making it a
matrix object. This is useful in combination with the index bracket
notation. Example:
\begin{screen}{1,2}
{m,n,p,q}::Indices.
A::Matrix.
V::ImplicitIndex.
(A V)_{m};
@expand!(%);
A_{m n} V_{n};
\end{screen}
Objects with the \subsprop{Matrix} property automatically become
non-commuting among themselves, but retain their commutativity
properties with other objects.
\begin{screen}{1,2}
{A,C}::Matrix.
A C B A;
@prodsort!(%);
A B C A;
\end{screen}
~

\cdbseealgo{prodsort}
\cdbseealgo{Spinor}
\cdbseeprop{ImplicitIndex}
