2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/75028Using the theory of almost conserved energies and the ``I-method'' developed by Colliander, Keel, Staffilani, Takaoka and Tao, we prove that the initial value problem for a higher order Schrödinger equation is globally well-posed in Sobolev spaces of order $s>1/4$.Analysis of PDEsMathematical Physics35A07; 35Q53text