The Chain Is Linear: The Squared Share's Last Reading, Closed at Second Order

Batch-2 P7 left one reading of the squared share's 40.9% flank alive: the eta_B = C*eps chain itself might be nonlinear at second order (P7's falsifier F2). This paper enumerates every second-order form the owned record can supply. Exact equilibrium at chemical potential is exactly cubic and terminates: its relative correction at the construction's eps_face = 6.927540e-8 is x^2/pi^2 = 4.86e-16, short of the needed +0.693353 by 1.43e15. Depletion dressings correct by -6.93e-8, wrong sign and seven orders small. Washout owns no Gamma/H at the address and its one statable direction points the wrong way. A general form C*eps*(1 + a*eps) needs a = 1.00086e7; no owned number sits there (211^3 is 6.1% under, 411^3 6.9x over, 1/eps_face refused as circular), and no integer g_b supplies the factor (required 3.386706). The chain is linear at owned scope; F2 does not fire; PD-889 is the construction's sole grader with no chain appeal.