“…These results were generalized to the O(n) vector ϕ 4 model by means of perturbation theory in combination with the renormalization group (RG) technique near the upper critical dimension [18,19,20,21,22,23] d = 2σ, lower critical dimension [24,25,26] d = σ, and the 1/n-expansion [27,28]. Computer simulations also contributed to the exploration of the critical properties of such systems [29,30,31,32,33,34,35].…”