long-ranged and statistical interactions mediated by a U (1) gauge field, both purely in 2+ 1
dimensions and on a surface in a (3+ 1)-dimensional bulk system. In the absence of
fractional spin, these theories have been shown to be self-dual under particle-vortex duality
and shifts of the statistical angle of the loops by 2 π, which form a subgroup of the modular
group, PSL (2, Z). We show that careful consideration of fractional spin in these theories …