IV.P136 — tau-Euler equation

In the Euler fluid regime the macroscopic defect tuple evolves as d/dn (mu_n, nu_n, kappa_n, theta_n) = (f_mu, f_nu, f_kappa, 0) with f_mu + f_nu + f_kappa = 0 (budget conservation) and theta_n = theta_0 for all n (topological invariance).