# On Schwinger-Dyson equations

A question about them (i have looked it up at wikipedia) Can they produce (a solution to them) a way to compute "Green functions" (and hence the propagator) in an "exact" (Non-perturbative approach) way?? .. for example the S-D equation read:

$$\frac{\delta S}{\delta \phi(x)}[-i \frac{\delta}{\delta J}]Z[J]+J(x)Z[J]=0$$ (1)

Then if we put the action S to be $$S[\phi]=\int d^{4}xL_{E-H}$$

where L is the Einstein-Hilbert Lagrangian..a solution to (1) if exist would be a form to compute the Green-function for the "Quantum Gravity"???:shy: