Inserting option `static` gives a list of exports that are available for S as a LHPDE object.
Basic properties of S can be got:
For a LHPDE object that is being reduced, we can find more information about the solution space of Q:
Q and R should regard as same LHPDEs system in the sense that they have same partial differential operator forms.
We can simplify the dependency of their dependent variables, for example, a new LHPDE object R1 is constructed with minimal dependencies.
A partial depended LHPDE object R1 has no trouble to be manipulated. For example, solving it..