Si. Shmarev et Jl. Vazquez, LAGRANGIAN COORDINATES AND REGULARITY OF INTERFACES IN REACTION-DIFFUSION EQUATIONS, Comptes rendus de l'Academie des sciences. Serie 1, Mathematique, 321(8), 1995, pp. 993-998
We study the regularity of solutions and interfaces of the reaction-di
ffusion equation mu(t) = (mu(n))(xx) + f(mu) by means of a formulation
in Lagrangian coordinates which transforms the interfaces into straig
ht lines. We thereby show how Lagrangian coordinates can be applied to
non-divergence equations where the mass conservation law is violated.