Symmetries of 2-D gravity

Two-dimensional gravity in the light-cone gauge was shown to exhibit an underlying sl(2, R) current algebra. It is the purpose of this note to offer a possible explanation about the origin of this important algebra. The essential point is that two-dimensional gravity is governed by a topological field theory. The gauge group is sl(2, R) and it is this enhanced gauge group that yields Polyakovʹs current algebra.