Journal of Stat&tical Physics, Vol. 63, Nos. 5/6, 1991. p. 1077-1096.
We consider a two-dimensional Ising cylinder of circumference M and height N, with a floating interface introduced by the appropriate boundary conditions. An exact analysis of the finite-size effects in surface tension is given and the scaling function for all temperatures is calculated. The results are compared with the
Monte Carlo data of Mon and Jasnow.