Un'aggiunta alla mia nota : regolarità parziale delle soluzioni di sistemi ellittici quasi lineari di ordine arbitrario
We show the existence of weak solutions in the extended sense of the Cauchy problem for the cubic fourth order nonlinear Schrödinger equation with the initial data , where and , , or , or . Moreover, if , or if , or if and we show that the Cauchy problem is unconditionally wellposed in . Similar results hold true for all higher order nonlinear Schrödinger equations and mixed order NLS due to a factorization property of the corresponding phase factors. For the proof we employ the normal...