“…For instance, it is well-known that both the van der Waals EoS and the general theory of the Landau theory of phase transitions predict the compressibility critical exponent γ = γ′ to be 1, and all known empirical EoS fail to exactly reproduce the experimental values γ = 1.2 ~1.3 ≳ γ′ = 1.1 ~1.2 [16,17]. Recently, we have conjectured that the Gaussian curvature of the local shape of the vaporliquid critical point is zero [18]. In the present study, we first prove that the conjecture is true and secondly report the construction of a fluid EoS, which has γ = γ′ = 3, which is quantitatively different from the experimental values but leads to the zero Gaussian curvature of the vapor-liquid critical point.…”