Parabolic - hyperbolic boundary layer
  A boundary value problem related to a parabolic higher order operator with a small parameter is analized. When the small parameter tends to zero, the reduced operator is hyperbolic. When t tends to infinity a parabolic hyperbolic boundary layer appears. In this paper a rigorous asymptotic approximation uniformly valid for all t is established. 
Monica De Angelis
math-ph cond-mat.supr-con math.MP