The electromagnetic photon has 4 covariant components, each of which may be taken to act on a 1-dimensional S1 subspace of
T4 = S1 x S1 x S1 x S1, each U(1) corresponding to the x, y, z, and t covariant components of the U(1) photon, giving the 4-dimensional Lagrangian, with curvature Fem4 and Dirac operator g¶e,
º ( - Fem4/\*Fem4 + `S8± g¶e S8± ) .
V(M) = 4V(S1) and V(Q)/(V(D)1/m) = 1, so the resulting volume for U(1) electromagnetism is
4V(S1) &endash; 1 = 4(2¹) = 8¹ = 4 x 6.2831853 = 25.132741 .
The relative geometric force strength of U(1) electromagnetism is the ratio of its volume to the volume of the force with the greatest geometric volume, Spin(5) anti-de Sitter gravitation, for which the calculation is made independently in Section 3.4.:
aE = (4V(S1))/(V(S4)V(Q5+)/(V(D5+)^1/4) = 1/137.03608 .
U(1) electromagnetism has no mass factor.
The characteristic distance of U(1) electromagnetism is about the size of an atom, the electromagnetic bohr radius 1/aEme Å 5 x 10^-9 cm, with energy about 4 Kev.