Finding unique groups. Here we show an example where 10 galaxy sets are connected by a network of MaNGA galaxies. For each set, we give the richness 𝒩 and the redshift of the ‘host’ MaNGA galaxy. The starting set is set S₁, and its member galaxies are emphasised in bold. The final representative sets selected by the selector are sets S₁, S₉ and S₁₀ which are indicated by thick borders. These three sets do not share any MaNGA galaxies, but may share SDSS galaxies not observed with MaNGA (see text). This example has many possible solutions (see the text for details).