  We consider infinite dimensional port-Hamiltonian systems. Based on a power
balance relation we introduce the port-Hamiltonian system representation where
we pay attention to two different scenarios, namely the non-differential
operator case and the differential operator case regarding the structural
mapping, the dissipation mapping and the in/output mapping. In contrast to the
well-known representation on the basis of the underlying Stokes-Dirac structure
our approach is not necessarily based on using energy-variables which leads to
a different port-Hamiltonian representation of the analyzed partial
differential equations.
