@misc{gfp_map_su_4_to_psu_4,
  author = {{Groups for Physics}},
  title = {SU(4) → PSU(4)},
  howpublished = {Groups for Physics reference},
  url = {https://groups.qft.org/atlas/maps/su-4-to-psu-4/},
  version = {2026.11-workbench.4},
  note = {Research workbench IV; review status recorded on canonical page}
}