correlation
transformation of a d-dimensional projective space that maps subspaces of dimension k to subspaces of dimension d − k − 1, reversing inclusion and preserving incidence
en-US/ˌkɑɹəˈleɪʃən/
en-GB/ˌkɒɹəˈleɪʃn/
transformation of a d-dimensional projective space that maps subspaces of dimension k to subspaces of dimension d − k − 1, reversing inclusion and preserving incidence