Theorem: V beta H rho - curl tau = 0 (Sverdrup interior balance)

Theorem (Sverdrup-residual canonical): beta V = curl tau/(rho H) cleared gives V beta H rho = curl tau, residual V beta H rho - curl tau = 0 identically. Canonical sympy pin: beta_s, H, rho, curl_tau = sp.symbols('beta_s H rho curl_tau',…