Robustness test of our t-SNE-selected subsamples to abundance errors. The left panel shows the fiducial map, while the right panel shows the result of our Monte-Carlo test. For each star, 50 random stars were drawn from a Gaussian centred on the measured abundance, and with dispersions corresponding to the measured uncertainties. t-SNE was then run on this artificially increased sample. The resulting map (for p = 40) shows the positions of each Monte-Carlo realisation as faint grey dots, and the median position of each star as the same big symbol as in the fiducial map. The experiment demonstrates that most of our selected subgroups are robust to doubling the observational errors of the HARPS sample.