@article{oai:ynu.repo.nii.ac.jp:00006916,
 author = {Avgerinos, Evgenios P. and Papageorgiou, N. S.},
 issue = {1},
 journal = {Yokohama Mathematical Journal = 横濱市立大學紀要. D部門, 数学},
 month = {},
 note = {application/pdf, In this paper we consider a very general second order nonlinear parabolic boundary value problem. Assuming the existence of an upper solution ＄￥varphi＄ and a lower solution ＄￥psi＄ satisfying ＄￥psi￥leq￥varphi＄ , we show that the problem has extrenal periodic solutions in the order interval ＄K=[￥psi)￥varphi]＄ . Our proof is based on a general surjectivity result for the sum of two operators of monotone type and on truncation and penalization techniques. In addition we use a result of independent interest which we prove here and which says that the pseudomonotonicity property of ＄A(t, ￥cdot)＄ can be lifted to its Nemitsky operator. Finally when we impose stronger conditions on the data, we show that the extrenal solutions can be obtained with a monotone iterative process.},
 pages = {39--60},
 title = {ON THE EXISTENCE OF EXTRENAL PERIODIC SOLUTIONS FOR NONLINEAR PARABOLIC PROBLEMS WITH DISCONTINUITIES},
 volume = {45},
 year = {1998}
}