  Generalizing response theory of open systems far from equilibrium is a
central quest of nonequilibrium statistical physics. Using stochastic
thermodynamics, we develop an algebraic method to study the response of
nonequilibrium steady state to arbitrary perturbations. This allows us to
derive explicit expressions for the response of edge currents as well as
traffic to perturbations in kinetic barriers and driving forces. We also show
that these responses satisfy very simple bounds. For the response to energy
perturbations, we straightforwardly recover results obtained using nontrivial
graph-theoretical methods.
