The translational correlation function decays fast, i. e. exponential, in the hexatic phase. In a 2D crystal, the translational order is quasi-long range and the correlation function decays rather slow, i. e. algebraic; It is not perfect long range, as in three dimensions, since the displacements u → → ( R → → ) diverge logarithmically with systems size at temperatures above T=0 due to the Mermin-Wagner theorem.