Four [hs/ls] indices (where ls = Zr or Y, and hs = Ba or La) as a function of the [s/r] index [La/Eu]. Symbols are as in Fig. 7. Theoretical predictions for 1 and 2 M_⊙ AGB stars at different metallicities, as labelled, are overplotted. For the 2 M_⊙ models the cyan line represents the evolution of the abundances along the AGB, whereas the blue and red lines represents the dilution of tip-of-the-AGB material in the envelope of the companion, ultimately producing material of solar abundance ([Ba/Zr] = 0, [La/Eu] = 0, [La/Zr] = 0). Since the 1 M_⊙ models experience a single thermal pulse, the cyan line reduces to a single point in that case and the red lines represent the mere dilution as above for the blue lines. We note that the 1 M_⊙ model predictions at [Fe/H] = −2.5 and −3 almost exactly superimpose.