Singular Perturbation Problems

This theory is devoted to study problems with small diffusion velocity. One is mainly concerned with the asymptotic behavior of the solution of such problems when the diffusion velocity approaches 0. Let us explain the situation on a classical example (see Lions (Quelques methodes de résolution des problèmes aux limites non lineaires. Dunod–Gauthier–Villars, Paris, 1969; Perturbations singulières dans les problèmes aux limites et en contrôle optimal.Lecture Notes in Mathematics, vol. # 323 (Springer, Berlin, 1973)).