Top panel: centripetal acceleration curves in g2 space with the quantities r_tot, r_N, and 𝒞^±, used for classification in Table 1, shown. The solid grey line shows a MOND MI curve with the radius of maximum baryonic acceleration and maximum total acceleration r_N = r_tot indicated. Also, the curve segments 𝒞⁺ and 𝒞⁻ coincide, so the curve area is 𝒜(𝒞) = 0. The dotted grey and dotted black curves show the 𝒞^± curve segments of a MOND MG curve, using the Brada-Milgrom approximation in Eq. (9), with r_tot >  r_N and 𝒜(𝒞) > 0. For both, the baryonic matter is an infinitely thin exponential disc, Σ(r) = Σ₀e^−r/r_d. The arrow indicates the direction of increasing radius along the curve. Bottom panel: corresponding rotation curves.