\cdbproperty{SelfAntiCommuting}{}

Used to make objects with indices anti-commuting when their index
values are different. Example:
\begin{screen}{1,2,3,5,6}
\psi^{\mu}::SelfAntiCommuting.
\psi^{\nu} \psi^{\mu}:
@prodsort!(%);
(-1) \psi^{\mu} \psi^{\nu};
\psi^{\mu} \psi^{\mu}:
@canonicalise!(%);
0;
\end{screen}
This could not be handled with \subsprop{AntiCommuting} because that
property handles the behaviour of \emph{different} expression patterns.

\cdbseealgo{AntiCommuting}
