V.T208 — Two-Channel Interpolation Theorem

Two-Channel Interpolation Theorem: the decomposition g² = g_N² + g_N·a₀ defines ν_2ch(y) = √(1+1/y) with y = g_N/a₀. Newtonian limit (y>>1): ν→1, g→g_N. Deep regime (y<<1): ν→1/√y, g→√(g_N·a₀), giving v⁴ = GM·a₀ (BTFR). Both asymptotic regimes agree with standard μ_τ interpolation.