Mr. Laydi, A PENALTY METHOD FOR SOLVING PARTIAL-DIFFERENTIAL EQUATIONS WITH BOUNDARY PERIODIC CONDITIONS, Comptes rendus de l'Academie des sciences. Serie 1, Mathematique, 324(3), 1997, pp. 339-342
We present a method based on penalization technique for solving an ell
iptic problem with periodic boundary conditions. The convergence of th
e method is proved and an error estimation is given.