São Paulo Journal of Mathematical Sciences https://doi.org/10.1007/s40863-019-00144-5 ORIGINAL PAPER Initial boundary value problems for some nonlinear dispersive models on the half-line: a review and open problems Márcio Cavalcante 1 © Instituto de Matemática e Estatística da Universidade de São Paulo 2019 Abstract In the last years the study of initial boundary value problems for nonlinear dispersive equations on the half-lines has given attention of many researchers. This turns out to be a rather challenging problem, mainly when studied in low Sobolev regularity. In this note we present a review of the main results about this topic and also introduce interesting open problems which still requires attention from the mathematical point of view. Keywords Initial boundary value problems · Nonlinear dispersive equations · Open problems Mathematics Subject Classification 35Q53 · 35Q55 · 35G31 1 Introduction In this note, we comment some recent results of the initial boundary value problems (IBVPs) for some nonlinear dispersive models in the form i t u (x , t ) (i x ) j u (x , t ) = N (u ,∂ x u (x , t ),...,∂ k x u (x , t )), x I , t (0, T ) u (x , 0) = u 0 (x ), x I (1.1) where, j and k are integer numbers, the set I is the positive half-line R + or the negative R and N is a nonlinear function. Models in the form (1.1) is considered with an appropriate number of conditions on the boundary x = 0, which depends of the dispersion term (i x ) j and it is given by the physical condition of the model. Note that, in the case, where j is a odd number equation (1.1) changes his behavior when B Márcio Cavalcante marciocavalcante@im.ufal.br 1 Instituto de Matemática, Universidade Federal de Alagoas, Maceió, AL 50740-545, Brazil 123