Histogram analysis of Monte-Carlo simulation results of the Ising antiferromagnet on a stacked triangular lattice are reported. Finite-size scaling estimates for critical exponents suggest $XY$ universality. This result supports earlier predictions based on symmetry arguments and is in contrast with a recent suggestion of a new universality class by Bunker { \it et al.} [Phys. Rev. B { \bf 48}, 15861 (1993)].
Categories: cond-mat