A regularization method for ill-posed bilevel optimization problems
  We present a regularization method to approach a solution of the pessimistic formulation of ill -posed bilevel problems . This allows to overcome the difficulty arising from the non uniqueness of the lower level problems solutions and responses. We prove existence of approximated solutions, give convergence result using Hoffman-like assumptions. We end with objective value error estimates. 
Ma\"itine Bergounioux (MAPMO), Mounir Haddou (MAPMO)