  The [dual] string tension of a spatial 't Hooft loop in the deconfined phase
of Yang-Mills theory can be formulated as the tension of an interface
separating different Z_N deconfined vacua. We review the 1-loop perturbative
calculation of this interface tension in the continuum and extend it to the
lattice. The lattice corrections are large. Taking these corrections into
account, we compare Monte Carlo measurements of the dual string tension with
perturbation theory, for SU(2). Agreement is observed at the 2% level, down to
temperatures O(10) T_c.
