Comments on ``The Einstein-Hilbert Lagrangian Density in a 2-dimensional Spacetime is an Exact Differential'' by R. da Rocha and W.A. Rodrigues, Jr

摘要

We argue that the recent result of da Rocha and Rodrigues that in twodimensional spacetime the Lagrangian of tetrad gravity is an exact differential[1], despite the claim of the authors, neither proves the Jackiw conjecture[2], nor contradicts to the conclusion of [3]. This demonstrates that thetetrad formulation is different from the metric formulation of theEinstein-Hilbert action.