Python 3.9.6; SymPy 1.14.0
Exact symbolic arithmetic; coordinates (theta, chi, t).
Curvature convention: R(X,Y)Z = [nabla_X,nabla_Y]Z - nabla_[X,Y]Z.
PASS: all Christoffel torsion, metric-compatibility, curvature and Ricci components.
Ricci in coordinate basis: Matrix([[1, 0, 0], [0, sin(theta)**2, 0], [0, 0, 0]])
R(partial_theta,partial_chi)partial_chi: (sin(theta)**2, 0, 0)
R(partial_theta,partial_t)partial_t: (0, 0, 0)
PASS: arbitrary-phi conformal curvature formula, all 81 components.
PASS: arbitrary-A flatness equations inconsistent; ranks 9 and 10.
Projective Weyl: W^t_(t theta theta) = -1/2 (nonzero).
PASS: non-self-dual torsion, cubic symmetry, duality, geodesic acceleration and composition.
Nonzero cubic component: C_ttt = -3*exp(t)
PASS: compatible Euclidean and constant-curvature controls accepted.
PASS: omitted-rescaling negative control rejected; cubic symmetry residual = -1.
SUCCESS: 403 explicit exact checks; no Python assert statements.
Scope: tensor identities only; radial integrability and original-source interpretation require the proof/audit.
