Comment on the universality class of self-avoiding walks on a two-layer square lattice

We have calculated exactly the mean-square radius of gyration and the mean-square distance of a monomer from the origin for n-step self-avoiding walks on a two-layer square lattice up to 24 steps. We estimated two universal amplitude ratios and the results provide additional evidence that self-avoiding walks on a two-layer lattice belongs to the same universality class as the self-avoiding walk on a planar lattice.