Mean crossover functions for uniaxial 3D ising-like systems

We give simple expressions for the mean of the max and min bounds of the critical-to-classical crossover functions previously calculated [Bagnuls and Bervillier, Phys. Rev. E 65, 066132 (2002)] within the massive renormalization scheme of the F 4 d (n) model in three dimensions (d = 3) and scalar order parameter (n = 1) of the Ising-like universality class. Our main motivation is to get efficient theoretical expressions to coherently account for many measurements performed in systems where the approach to the critical point is limited but yield data which are still reproducible by the F 4 d (n) model (like in the subclass of one-component fluids).