IV.T133 — EM Tensor Density Theorem

The EM-sector density in A_spec(L)^{⊗2} is exactly 121/225 = (11/15)². Of the 225 mode pairs, 121 are jointly EM-active. This is the coefficient in α = (121/225)·ι_τ⁴, derived as a single computation on the tensor-square algebra.