@misc{gfp_map_u_1_to_so_3,
  author = {{Groups for Physics}},
  title = {U(1) ≅ SO(2) ↪ SO(3)},
  howpublished = {Groups for Physics reference},
  url = {https://groups.qft.org/atlas/maps/u-1-to-so-3/},
  version = {2026.11-workbench.4},
  note = {Research workbench IV; review status recorded on canonical page}
}