Non-Canonicity of the Subleading Depth Drift and Structural Closure of the Evans Arc

Research Note 32 in the "Geometry of the Critical Line" programme. This note establishes numerically that the Evans asymptotic arc terminates at leading order not by convenience but by structure. The Riccati remainder functional R_m(λ) = ∫ [P_exact − P_WKB] dδ is examined at multiple endpoint cutoffs η. Three results: (1) the real part Re(R_m) stabilises as η → 0, providing numerical evidence for an η-independent global phase defect in the spacing sector; (2) the imaginary part Im(R_m) diverges logarithmically in η and is therefore not matching-invariant; (3) consequently, the subleading depth drift c_m/√x is a scheme-dependent global matching quantity and does not admit a canonical analytic representative…