Solution of the initial value problem for the focusing Davey-Stewartson II system

The first author was supported by Portuguese funds through the CIDMA - Center for Research and Development in Mathematics and Applications and the Portuguese Foundation for Science and Technology (“FCT–Fundacao para a Ciencia e a Tecnologia”), within project UID/MAT/0416/2013. The second author was supported by the NSF grant DMS-1410547.