Recurrence for the Right-Hand Side

We obtain a recurrence for the right-hand side by applying Mgfun[sum_of_sys] on the system computed in the previous section.

> sum_of_sys(sys,k=-infinity..infinity,takayama_algo);

This recurrence is different from the one obtained for the left-hand side.

> rec[right]:=op(collect(",h,factor));

We thus need more work to prove that both sides agree.