Theoretical distribution for the initial carbon, nitrogen, oxygen, sodium, magnesium, and aluminum abundances ([X/Fe] = log(X/Fe)_⋆–log(X/Fe)_⊙) for [C/N] and for ¹²C/¹³C (initial value of 90) as a function of the initial helium mass fraction adopted for our 2P stars models (black line; dots indicate the 16 values adopted for the model computations of each stellar mass between 0.3 and 1 M_⊙). This accounts for dilution between original 1P material and the ejecta of the 60 and 120 M_⊙ FRMS models (red and blue lines, respectively; Decressin et al. 2007b) as described in Eq. (1) (see text). The magenta arrows represent the variations observed in NGC 6752 for [C/Fe] and [N/Fe] (Carretta et al. 2005), [O/Fe] and [Na/Fe] (Carretta et al. 2007), and [Mg/Fe] and [Al/Fe] (Carretta et al. 2012).