V.T174 — PMNS Shared Eigenvector Structure: Identity from sigma-Polarity

Both neutrino and charged-lepton sigma-polarity matrices share the SAME eigenvector structure (sigma-symmetric tridiagonal form): v_sigma-odd=[1,0,-1]/sqrt(2), v_sigma-even determined by (a-c) and b. Therefore PMNS=V_l^dagger * V_nu approx identity from sigma-structure alone. Physical interpretation: sigma-polarity structure generates mass eigenstates; flavor mixing (PMNS) requires additional A-sector rotation (Lobe1,Crossing,Lobe2)->(nu_e,nu_mu,nu_tau). If V_l=identity: theta13=9.85 (PDG 8.57, +15%), theta12=45.86 (PDG 33.4, fails), theta23=80.01 (PDG 42.0, fails). Full PMNS requires Sprint 5 A-sector rotation.