  Thermal and chiral critical exponents of the fully frustrated XY model on a
square-lattice are obtained from a finite-size scaling analysis of the free
energy of chiral domain walls. Data were obtained by extensive Monte Carlo
transfer matrix computations for infinite strips of widths up to $14$ lattice
spacings. Two transfer matrices were implemented, one for each of the two
principal lattice directions. The results of both are consistent, but the
critical exponents differ significantly from the pure Ising values. This is in
agreement with other recent Monte Carlo simulations. Our results also support
the identification of the critical behavior of this model with that along the
line of transitions of simultaneous ordering or becoming critical of Ising and
planar rotor degrees of freedom in the XY-Ising model studied recently.
