## On periodic solutions of a parabolic problem with a small parameter at the derivatives.(Russian, English)Zbl 1136.35306

Zh. Vychisl. Mat. Mat. Fiz. 43, No. 7, 975-986 (2003); translation in Comput. Math. Math. Phys. 43, No. 7, 932-943 (2003).
A boundary value problem is considered for a singularly perturbed parabolic equation that involves a small parameter multiplying all derivatives and degenerates into a finite equation when the parameter is equal to zero. An existence theorem is proved for a periodic solution with an internal layer, i.e., for a steplike contrast structure. A theorem on passage to the limit when the small parameter vanishes is proved as well.

### MSC:

 35B10 Periodic solutions to PDEs 35B25 Singular perturbations in context of PDEs 35K55 Nonlinear parabolic equations