The Spectral Discriminant of η = 49/120 : 120 = 7² + 71 as a Topological Partition of Biological Timescales

Abstract We report an unexpected topological property of the T144 spectral invariant η = 49/120. The complement of the numerator 49 within Z₁₂₀ is 71, a prime number, yielding the partition 120 = 49 + 71. We prove that this partition is unique in Z₁₂₀: among all squares of primes less than 120, only 49 = 7² has a prime complement (71). Furthermore, both 49 and 71 are invertible in Z₁₂₀, with the remarkable property 49² ≡ 1 (mod 120) and 71² ≡ 1 (mod 120) — both are self-inverse involutions of Z₁₂₀. This partition induces a natural spectral discriminant on biological timescales: the 14 divisors of 120 that fall in the class A₄₉ = {n ≤ 49} govern all macrotemporal biological periods (T ≥ 3 units), while the 2 divisors in B₇₁ = {n > 49} govern only the fastest sub-cycles (T ≤ 2 units). The action η = 49/120 is therefore not only a topological invariant but a discriminant operator: it separates Z_n subgroups that govern observable biological processes from those that govern non-observable sub-threshold transitions. Keywords: spectral discriminant, 120 = 49 + 71, topological partition, Z₁₂₀, self-inverse involution, biological timescales, η-invariant, T144