Dynamics of the conformal mode and simplicial gravity

We review the derivation of the Liouville action in 2DQG via the trace anom aly and emphasize how a similar approach can be used to derive an effective action describing the long wavelength dynamics of the conformal factor in 4D. In 2D we describe how to make an explicit connection between dynamical triangulations and this continuum theory, and present results which confirm the equivalance of the two approaches. By reconstructing a lattice conform al mode from DT simulations it should be possible to test this equivalence in 4D also.