

\poisson{#}::Derivative.
{ A_{a b}(x?), B^{a b}(y?) }::Depends(\poisson).

\poisson( Q(x) A_{a b}(x) R(x') A_{e f}(x') )( S B^{c d}(y) T(y') B^{g h}(y') );

@prodrule!(%);
@prodrule!(%);

@distribute!(%);

@unwrap!(%);

@substitute!(%)( 
  \poisson( A_{a b}(x?) )( B^{c d}(y?) ) = \delta_{a}^{c} \delta_{b}^{d} \delta(x?,y?) );


\poisson(   \partial(A_{a b}(x))_{x}   )(  B^{c d}(x')  );

@substitute!(%)( \poisson( \partial( A?? )_{x} )( B?? ) -> \partial(\poisson( A?? )( B?? ) )_{x} );
